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Söhnel K, Fischer M, Häusler K. Treadmill vs. overground trotting - a comparison of two kinetic measurement systems. Res Vet Sci 2022; 150:149-155. [DOI: 10.1016/j.rvsc.2022.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 05/02/2022] [Accepted: 06/05/2022] [Indexed: 11/30/2022]
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Buchholtz ML, Arend FM, Eichhorn P, Weigand M, Kleinhempel A, Häusler K, Bruegel M, Holdt LM, Teupser D. SARS-CoV-2 antibody immunoassays in serial samples reveal earlier seroconversion in acutely ill COVID-19 patients developing ARDS. PLoS One 2021; 16:e0251587. [PMID: 33984048 PMCID: PMC8118560 DOI: 10.1371/journal.pone.0251587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/28/2021] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVES During the COVID-19 pandemic, SARS-CoV-2 antibody testing has been suggested for (1) screening populations for disease prevalence, (2) diagnostics, and (3) guiding therapeutic applications. Here, we conducted a detailed clinical evaluation of four Anti-SARS-CoV-2 immunoassays in samples from acutely ill COVID-19 patients and in two negative cohorts. METHODS 443 serum specimens from serial sampling of 29 COVID-19 patients were used to determine clinical sensitivities. Patients were stratified for the presence of acute respiratory distress syndrome (ARDS). Individual serum specimens from a pre-COVID-19 cohort of 238 healthy subjects and from a PCR-negative clinical cohort of 257 patients were used to determine clinical specificities. All samples were measured side-by-side with the Anti-SARS-CoV-2-ELISA (IgG), Anti-SARS-CoV-2-ELISA (IgA) and Anti-SARS-CoV-2-NCP-ELISA (IgG) (Euroimmun AG, Lübeck, Germany) and the Elecsys Anti-SARS-CoV-2 ECLIA (Roche Diagnostics International, Rotkreuz, Switzerland). RESULTS Median seroconversion occurred earlier in ARDS patients (8-9 days) than in non-ARDS patients (11-17 days), except for EUR N-IgG. Rates of positivity and mean signal ratios in the ARDS group were significantly higher than in the non-ARDS group. Sensitivities between the four tested immunoassays were equivalent. In the set of negative samples, the specificity of the Anti-SARS-CoV-2-ELISA (IgA) was lower (93.9%) compared to all other assays (≥98.8%) and the specificity of Anti-SARS-CoV-2-NCP-ELISA (IgG) was lower (98.8%) than that of Elecsys Anti-SARS-CoV-2 (100%). CONCLUSIONS Serial sampling in COVID-19 patients revealed earlier seroconversion and higher signal ratios of SARS-CoV-2 antibodies as a potential risk marker for the development of ARDS, suggesting a utility for antibody testing in acutely diseased patients.
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Affiliation(s)
| | - Florian M. Arend
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Peter Eichhorn
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Michael Weigand
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Alisa Kleinhempel
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Kurt Häusler
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Mathias Bruegel
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Lesca M. Holdt
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
| | - Daniel Teupser
- Institute of Laboratory Medicine, University Hospital, LMU Munich, Munich, Germany
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Warden L, Moros M, Neumann T, Shennan S, Timpson A, Manning K, Sollai M, Wacker L, Perner K, Häusler K, Leipe T, Zillén L, Kotilainen A, Jansen E, Schneider RR, Oeberst R, Arz H, Sinninghe Damsté JS. Climate induced human demographic and cultural change in northern Europe during the mid-Holocene. Sci Rep 2017; 7:15251. [PMID: 29127307 PMCID: PMC5681586 DOI: 10.1038/s41598-017-14353-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 10/09/2017] [Indexed: 12/28/2022] Open
Abstract
The transition from hunter-gatherer-fisher groups to agrarian societies is arguably the most significant change in human prehistory. In the European plain there is evidence for fully developed agrarian societies by 7,500 cal. yr BP, yet a well-established agrarian society does not appear in the north until 6,000 cal. yr BP for unknown reasons. Here we show a sudden increase in summer temperature at 6,000 cal. yr BP in northern Europe using a well-dated, high resolution record of sea surface temperature (SST) from the Baltic Sea. This temperature rise resulted in hypoxic conditions across the entire Baltic sea as revealed by multiple sedimentary records and supported by marine ecosystem modeling. Comparison with summed probability distributions of radiocarbon dates from archaeological sites indicate that this temperature rise coincided with both the introduction of farming, and a dramatic population increase. The evidence supports the hypothesis that the boundary of farming rapidly extended north at 6,000 cal. yr BP because terrestrial conditions in a previously marginal region improved.
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Affiliation(s)
- L Warden
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, 1790 AB Den Burg, Texel, The Netherlands
| | - M Moros
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany.
| | - T Neumann
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany
| | - S Shennan
- Institute of Archaeology, University College London, 31-34 Gordon Square, London, WC1H 0PY, UK
| | - A Timpson
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London, WC1E 6BT, UK
| | - K Manning
- Department of Geography, King's College London, London, WC2R 2LS, UK
| | - M Sollai
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, 1790 AB Den Burg, Texel, The Netherlands
| | - L Wacker
- Laboratory of Ion Beam Physics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
| | - K Perner
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany
| | - K Häusler
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany
| | - T Leipe
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany
| | - L Zillén
- Geological Survey of Sweden, Department of Marine Geology, Box 670, 751 28, Uppsala, Sweden
| | - A Kotilainen
- Geological Survey of Finland, P.O. Box 96, 02151, Helsinki, Finland
| | - E Jansen
- Bjerknes Centre for Climate Research/Department of Earth Science, University of Bergen Allégaten 70, 5007, Bergen, Norway
| | - R R Schneider
- Insitute of Geosciences, Kiel University, Ludewig-Meyn Strasse 10, 24118, Kiel, Germany
| | - R Oeberst
- Institute of Baltic Sea Fisheries, Thünen Institute, Alter Hafen Süd 2, 18069, Rostock, Germany
| | - H Arz
- Leibniz Institute for Baltic Sea Research, Departments of Marine Geology and Physical Oceanography, Warnemünde, Germany
| | - J S Sinninghe Damsté
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht University, 1790 AB Den Burg, Texel, The Netherlands. .,Utrecht University, Faculty of Geosciences, P.O. Box 80.021, 3508 TA, Utrecht, The Netherlands.
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Oberheide J, Forbes JM, Häusler K, Wu Q, Bruinsma SL. Tropospheric tides from 80 to 400 km: Propagation, interannual variability, and solar cycle effects. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2009jd012388] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- J. Oberheide
- Physics Department; University of Wuppertal; Wuppertal Germany
| | - J. M. Forbes
- Department of Aerospace Engineering Sciences; University of Colorado; Boulder Colorado USA
| | - K. Häusler
- Helmholtz Centre Potsdam; German Research Centre for Geosciences; Potsdam Germany
| | - Q. Wu
- High Altitude Observatory; National Center for Atmospheric Research; Boulder Colorado USA
| | - S. L. Bruinsma
- Department of Terrestrial and Planetary Geodesy; CNES; Toulouse France
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Wenzel H, Häusler K, Blume G, Fricke J, Spreemann M, Zorn M, Erbert G. High-power 808 nm ridge-waveguide diode lasers with very small divergence, wavelength-stabilized by an external volume Bragg grating. Opt Lett 2009; 34:1627-1629. [PMID: 19488129 DOI: 10.1364/ol.34.001627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present data on ridge-waveguide diode lasers having a vertical far-field divergence of only 11.5 degrees (FWHM) owing to an appropriate waveguide design. The lasers emitted an optical power of more than 1 W into the spatial fundamental mode from a ridge width of 5 microm. The emission wavelength was stabilized to a narrow range around 808 nm by placing a volume Bragg grating in front of the outcoupling facet.
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Affiliation(s)
- H Wenzel
- Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany.
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Lühr H, Rother M, Häusler K, Alken P, Maus S. The influence of nonmigrating tides on the longitudinal variation of the equatorial electrojet. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008ja013064] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- H. Lühr
- GeoForschungsZentrum Potsdam; Potsdam Germany
| | - M. Rother
- GeoForschungsZentrum Potsdam; Potsdam Germany
| | - K. Häusler
- GeoForschungsZentrum Potsdam; Potsdam Germany
| | - P. Alken
- Cooperative Institute for Research in Environmental Sciences; University of Colorado; Boulder Colorado USA
| | - S. Maus
- Cooperative Institute for Research in Environmental Sciences; University of Colorado; Boulder Colorado USA
- National Geophysical Data Center; NOAA; Boulder Colorado USA
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Eugster M, Häusler K, Reinhart WH. Viscosity measurements on very small capillary blood samples. Clin Hemorheol Microcirc 2007; 36:195-202. [PMID: 17361022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Viscosity measurements on very small capillary blood samples could be of considerable clinical interest. We have developed an oscillating viscometer for very small volumes, which consists of a glass capillary containing 7 mul of blood, which is part of an oscillating torsional resonator. The damping of the sinusoidal oscillations depends on the density and viscosity of the fluid, which allows blood viscosity measurements. The instrument was first evaluated in comparison with a standard blood viscometer (Contraves LS 30). Blood from healthy volunteers anticoagulated with EDTA was adjusted to hematocrit levels of 20, 30, 40, 50, and 60%, respectively. A strong correlation was found between hematocrit and oscillating viscosity (y=0.17x-2.05, r=0.969, p<0.0001) and between oscillating and conventional high shear viscosity (y=1.11x-0.62, r=0.971, p<0.0001). Blood viscosity measured in venous or capillary blood of normal subjects was similar (p=0.63). Bedside viscosity measurements on capillary blood drawn from a finger prick during routine blood glucose measurements in patients with diabetes mellitus showed lower blood viscosity than controls (3.62+/-0.87 vs 4.79+/-0.59 mPa.s, p=0.0007), which is in contrast to earlier publications, and may be explained by the lower hematocrit in our diabetic patients (34.7+/-6.0% vs. 43.1+/-1.9%, p<0.0001). Blood viscosity was independent of the actual glucose level (range 3-17 mmol/l). Capillary blood anticoagulated with EDTA was drawn by heel prick from 23 newborns. Blood viscosity was higher (5.66 +/-2.47 mPa.s) than in adult controls (see above), which could be explained by the dependence on the higher hematocrit (46.4 +/-8.6%). We conclude that viscosity measurements can be made on very small samples such as capillary blood from diabetic patients or newborn babies with this new oscillating viscometer. It remains to be determined if such new informations have clinical implications.
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Affiliation(s)
- M Eugster
- Internal Medicine, Kantonsspital, Chur, Switzerland
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Mark M, Häusler K, Dual J, Reinhart WH. Oscillating viscometer--evaluation of a new bedside test. Biorheology 2006; 43:133-46. [PMID: 16687783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A viscometer for bedside blood measurements was developed, consisting of an oscillating resonator probe mounted directly into a disposable vacutainer tube for blood withdrawal. It was tested in vitro on blood samples with variable hematocrits (20-60%), increasing fibrinogen concentrations (0-20 g/l), increasing concentrations of an admixed radiographic contrast medium and erythrocyte suspensions in dextran 40 and dextran 70. Results were compared with those obtained with a conventional Couette viscometer. Oscillating viscometry yielded generally higher values than Couette viscometry, and had a good sensitivity for changes in hematocrit with a good correlation between the two methods (r=0.96, p<0.0001). Oscillating viscosity depended on the resonator frequency, it was higher at 3900 Hz than at 215 Hz, suggesting a viscoelastic behavior of blood. Erythrocyte aggregation, induced by increasing fibrinogen concentrations or dextran 70, affected oscillating viscometry. At a high frequency, i.e. a smaller penetration depth of the shear wave, oscillating viscosity tended to decrease, which suggests a depletion of the boundary layer from erythrocytes when they aggregate. At low frequency with a deeper shear wave penetration (about 50 microm), erythrocyte aggregation increased oscillating viscosity. Bedside tests in 17 patients with coronary heart disease and 10 controls confirmed the easy practicability of the test and showed lower oscillating viscosity in these patients despite higher fibrinogen concentrations presumably due to increased erythrocyte aggregation. We conclude that oscillating viscometry is an interesting bedside test, which is capable of providing new information on the biorheology of the erythrocyte-poor boundary layer near the vessel wall.
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Affiliation(s)
- M Mark
- Internal Medicine, Kantonsspital, CH-7000 Chur, Switzerland
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Reinhart WH, Häusler K, Schaller P, Erhart S, Stetter M, Dual J, Sayir M. Rheological properties of blood as assessed with a newly designed oscillating viscometer. Clin Hemorheol Microcirc 1998; 18:59-65. [PMID: 9653587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A newly designed type of oscillating viscometer was tested for blood viscosity measurements. The viscometer consists of a probe (either a tube or a rod) oscillating at a resonance frequency with amplitudes in the micro- and nanometer range. The torsional oscillations are dampened by fluids flowing through the tube or surrounding the rod. The degree of damping depends on the viscosity of the fluid, which allows to measure viscosity. Data obtained with these instruments were compared with those obtained with a conventional Couette viscometer. An increase of erythrocyte aggregation by the addition of dextran 70 in vitro led to the expected increase of viscosity in the Couette viscometer; in the oscillating tube viscometer, however, it remained unchanged, which may be explained by a decreased erythrocyte concentration near the tube wall due to increased aggregation and flow of erythrocytes in the tube center. In ex vivo experiments on blood flowing without anticoagulant directly through the tube viscometer an inverse correlation between viscosity and fibrinogen concentration was found. This is in contrast to actual knowledge and may indicate that high fibrinogen levels have a beneficial rheological effect at the tube or vessel wall. Our data suggest that the new oscillating tube viscometer is an interesting tool, which may contribute to a more comprehensive understanding of blood flow.
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Affiliation(s)
- W H Reinhart
- Internal Medicine, Kantonsspital, Chur, Switzerland
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Affiliation(s)
- K. Häusler
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
| | - W.H. Reinhart
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
| | - P. Schaller
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
| | - J. Dual
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
| | - J. Goodbread
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
| | - M. Sayir
- Institute of Mechanics, ETH Zürich, CH-8092 Zürich, Switzerland Phone: +41 01 6323570/ FAX: +41 01 632 11 45
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Häusler K, Eberl K, Noll F, Trampert A. Strong alignment of self-assembling InP quantum dots. Phys Rev B Condens Matter 1996; 54:4913-4918. [PMID: 9986453 DOI: 10.1103/physrevb.54.4913] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Abstract
A newly designed type of oscillating viscometer is described. The viscometer consists of either a tube or a rod oscillating at a resonance frequency with amplitudes in the micro- and nanometer range. A fluid flowing through the tube or surrounding the rod damps the torsional oscillations. The increase in the damping depends on the viscosity of the fluid and is used to determine viscosity. It was found that viscosity measurements are feasible during blood flow. This new type of viscometer may be useful to the study of biophysical properties of blood at the wall surface during flow and give new insights into blood flow. The device allows direct viscosity measurement on blood directly as it is drawn from the vein through the tube without any anticoagulant.
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Affiliation(s)
- K Häusler
- Institute of Mechanics, ETH Zürich, Switzerland
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Fischer-Brandies H, Scherer R, Theusner J, Häusler K. [Increasing the adhesion of glass ionomer cements in bracket bonding]. Fortschr Kieferorthop 1992; 53:131-6. [PMID: 1634158 DOI: 10.1007/bf02341447] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
For attaching orthodontic brackets glass ionomer cements are being discussed as an alternative material to synthetic glues since they are less aggressive toward the tooth enamel. A serious disadvantage consists in a lower degree of adhesion to enamel. The adhesion can, however, be increased to some extent by enamel preparation. In order to investigate further improvement in this area, 250 freshly extracted bovine teeth were treated with 22 chemicals and their enamel-conditioning properties were tested. For the attachment of the brackets the glass ionomer cements AqaCem and Ketac-cem are used. Tensile shear tests were carried out with a Wolpert universal testing machine. Best results were obtained with the aromatic carbonacids benzoic acid and salicylic acid in acetonic solution. The mean adhesive power was 9.8 MPa. This means an increase of 38% as compared to other pre-conditioning materials such as polyacrylic acid. It can be assumed, that aromatic carbonacids as small, very reactive molecules can establish a closer contact to the phosphate groups of enamel than can the macromolecular polyacrylic acid. Thus, a further step on the way to using glass ionomer cements as a bracket bonding material seems to have been taken.
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Abstract
In this article technical problems of surface-structured endoprostheses for cementless implantation are discussed. On the basis of four prostheses (two hip and two knee endoprostheses) various different porous coating technologies are compared. One sintered sphere layer, a cast sphere layer, a cast layer with "spongy-bone" structure and a plasma sprayed coating were compared. The quality of the bonding between the prosthesis and the porous surface layer was examined metallographically using polished specimens, with additional investigation of fraction surfaces of special tension test specimens. Additional information is given on the notch effect of the different coatings, in terms of a reduction in fatigue strength. The notch sensitivity differs for each material, and the reduction in fatigue strength is discussed for different implant alloys and different technologies for surface structuring. The investigation shows that the present quality of surface-structured endoprostheses is not satisfactory. We would like to thank the Dr. Johannes Heidenhain Foundation for financial support of this research.
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