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M Kanayama BW Cunningham JC Weis LM Parker K Kaneda PC McAfee 《Canadian Metallurgical Quarterly》1997,79(11):1710-1720
We investigated the temporal relationship among the biomechanical, radiographic, and histological properties of a posterolateral spinal fusion mass to elucidate the changes in load-sharing of the spinal instrumentation and that of the fusion mass throughout the healing process. Destabilization of the posterior spinal column and transpedicular screw fixation at the segments between the third and fourth and the fifth and sixth lumbar vertebrae was performed in twenty-four sheep. A posterolateral spinal arthrodesis with use of autologous corticocancellous bone graft was done randomly at one of the two segments; the other segment (without bone graft) served as the instrumented control. Six animals each were killed at four, eight, twelve, and sixteen weeks postoperatively. Biomechanical testing showed that the posterolateral fusion mass had increased mechanical stiffness after the fourth week. The strain on the hardware, measured with use of rods instrumented with strain-gauges, decreased significantly (p < 0.01) beginning at eight weeks. Radiographically, three independent observations of each of the six animals at each time-period showed that, although all of the fusion masses were considered solid unions at sixteen weeks, bridging of trabecular bone was noted during only ten of eighteen observations at twelve weeks, three of eighteen observations at eight weeks, and none of eighteen observations at four weeks. Computerized tomography and histomorphometric analyses demonstrated that mineralization in the fusion mass increased in a linear fashion even after eight weeks. Histologically, the fusion mass consisted predominantly of woven bone at eight weeks; thereafter, it was gradually trabeculated. CLINICAL RELEVANCE: We found a great discrepancy between biomechanical stability and histological maturation of the posterolateral fusion mass. The biomechanical properties of a stable spinal fusion preceded the radiographic appearance of a solid fusion by at least eight weeks, suggesting that immature woven bone provided substantial stiffness to the fusion mass. The spinal instrumentation was subjected predominantly to bending stress rather than to axial stress, and the load-sharing of the spinal instrumentation decreased concurrently with the development of the spinal fusion. 相似文献
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Jan Haas Karen S. Frese Farbod Sedaghat-Hamedani Elham Kayvanpour Rewati Tappu Rouven Nietsch Oguz Firat Tugrul Michael Wisdom Carsten Dietrich Ali Amr Tanja Weis Torsten Niederdrnk Michael P. Murphy Thomas Krieg Marcus Drr Uwe Vlker Jens Fielitz Norbert Frey Stephan B. Felix Andreas Keller Hugo A. Katus Benjamin Meder 《International journal of molecular sciences》2021,22(4)
With more than 25 million people affected, heart failure (HF) is a global threat. As energy production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM (p = 1.7 × 10−6). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting enzymes of these pathways could also be found and validated in our second stage of metabolite assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades that potentially represent suitable intervention targets. 相似文献
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G. Weis 《European Journal of Lipid Science and Technology》1969,71(3):226-231
Technique and Application of Gas Chromatography in the Field of Fats for the Soap Industry A short introductory review on the development of gas chromatography is followed by an explanation of the principles involved in the construction of a gas chromatograph with reference to the various detectors. The procedures for the esterification of fatty acids and interesterification of fats for gas chromatographic analysis are dealt with. The adjustment of a gas chromatograph as well as the modes for the evaluation of chromatograms constitute the subsequent discussions. Finally, the possibilities for the use of gas chromatography in the investigation of fats for the soap industry are shown. 相似文献
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Fifteen fresh cadaver impacts were conducted in simulation of pedestrian-automobile accidents. The test sled configuration simulated an automobile bumper and hood in "standard" and "nosedive" situations as well as "hard" and "soft" impact surfaces. Instrumentation and film demonstrated large axial compression forces in the struck leg and considerable angular velocity of the torso in all modes. Dissection revealed primary injury at the impact site at low velocities with added remote injury at high velocities. Fracture of the lateral tibial plateau was most common. Lowering the bumper height offered the greatest protection against injury at moderate impact velocities. 相似文献
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The proton magnetic resonance spectroscopic imaging techniques that use read gradient during acquisition produce proton spectra
with high spatial and moderately high spectroscopic resolution in a reasonable time forin vivo applications. These techniques suffer mainly from the spatial and pectral distortions caused by the convolution of spectral/spatial
information (chemical-shift artifacts) and from the spectral shifts caused by static magnetic field inhomogeneities. The investigators
analyze the chemical-shift artifacts in the presence of nonnegligible static magnetic field inhomogeneities and propose a
postdetection processing scheme to correct for such effects. Spectral artifacts caused by chemical shifts, spectral line overlapping,
streak broadening, and magnetic field inhomogeneities are discussed. The postdetection data processing scheme is demonstrated
on measurements of a phantom as well as a human leg.
Supported by the Swedish Medical Research Council, project B-96-17x-006676-14A, and by Uppsala University are gratefully acknowledged.
One of us (J.W.) is indebted to the Institute of Measurement Science, Slovak Academy of Sciences, for continuous support,
VEGA Grant No. 95/5305/585,468 & 2/1207/96 相似文献