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Your search keyword '"Stratmann, I."' showing total 11 results
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11 results on '"Stratmann, I."'

1. Developing elastic–plastic material models for pressure measurement films in a steel–steel contact for smooth and rough surfaces

Author

Stratmann, I., Goersch, J., Neuser, M., Schindler, C., Stratmann, T., Stratmann, I., Goersch, J., Neuser, M., Schindler, C., and Stratmann, T.

Abstract

The contact zone between two steel components can be identified by utilizing a pressure measurement film in the contact between them. To reduce the number of necessary experiments, it is possible to simulate the contact situation using “finite element analysis.” This analysis requires material models for the contact partners and for the pressure measurement films. It is known that the pressure measurement film deforms not only elastically but also plastically. Taking this plastic deformation into account requires an appropriate material model such as the Drucker–Prager model. Based on published data of experiments with pressure measurement films that had been inserted between smooth and rough Hertzian bodies, we developed material models for three pressure measurement films. The roughness of a Hertzian body was studied by determining multiple pressure–clearance curves for three different surface roughnesses and for three different pressure measurement films. These curves were developed with micromodels, which represented a small section of the rough contact surface. An average curve for each material was then implemented in the macromodel for each roughness representing the contact situation. Subsequently, the resulting contact areas were compared with the published experimental data. This comparison showed that the material model for the smooth contact was able to emulate the experimentally determined contact areas. Including the pressure–clearance curves in the material model allowed the simulation of the rough contact situation. However, the deviation between the simulated and the experimental data was slightly larger for the rough surface than for the smooth surface.

Published
2023

7. High-Affinity Copolymers Inhibit Digestive Enzymes by Surface Recognition.

Author

Gilles P, Wenck K, Stratmann I, Kirsch M, Smolin DA, Schaller T, de Groot H, Kraft A, and Schrader T

Subjects
Alanine chemistry, Aspartic Acid chemistry, Benzamidines chemical synthesis, Catalytic Domain, Diphosphonates chemical synthesis, Enzyme Assays, Enzyme Inhibitors chemical synthesis, Glutamic Acid chemistry, Humans, Kinetics, Pancreatic Elastase antagonists & inhibitors, Polymerization, Polymers chemical synthesis, Protein Binding, Benzamidines chemistry, Diphosphonates chemistry, Enzyme Inhibitors chemistry, Pancreatic Elastase chemistry, Polymers chemistry, Serine Proteases chemistry
Abstract

This account presents a general method for the construction of polymeric surface binders for digestion enzymes. Two prominent parts, namely, the modification of the copolymer composition and the screening assay for the most powerful inhibitors are both amenable to parallelization. The concept hinges on the appropriate selection of amino-acid-selective comonomers, their free radical copolymerization, and subsequent screening of the resulting copolymer library for efficient enzyme inhibition. A microscale synthetic procedure for the copolymerization process was developed, which produces water-soluble affinity polymers that can be stored for years at room temperature. Initial parallel screening was conducted in standard enzyme assays to identify polymeric inhibitors, which were subsequently subjected to determination of IC 50 values for their target enzyme. For all digestion enzymes, except elastase, a number of polymer inhibitors were found, some of which were selective toward one or two protein targets. Since the key monomers of the best inhibitors bind to amino acid residues in the direct vicinity of the active site, we conclude that efficient coverage of the immediate environment by the copolymers is critical. Strong interference with enzymatic activity is brought about by blocking the substrate access and product exit to and from the active site.

Published
2017
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9. Cytoplasmic microfilaments in the anterior lobe of the human pituitary gland.

Author

Kovacs K, Horvath E, Stratmann IE, and Ezrin C

Subjects
Acromegaly etiology, Adenoma, Acidophil complications, Cytoplasmic Granules, Endoplasmic Reticulum, Female, Glucocorticoids pharmacology, Golgi Apparatus, Humans, Hypopituitarism etiology, Microscopy, Electron, Mitochondria, Pituitary Gland drug effects, Pituitary Neoplasms complications, Cytoplasm, Pituitary Gland cytology
Published
1974
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11. Effect of TRH (thyrotropin-releasing hormone) on the fine structure and replication of TSH and prolactin cells in the rat.

Author

Stratmann IE, Ezrin C, Kovacs K, and Sellers EA

Subjects
Animals, Autoradiography, Cell Count, Cell Division drug effects, Cell Membrane, Cell Nucleus, Cytoplasmic Granules, Endoplasmic Reticulum, Male, Microscopy, Microscopy, Electron, Pituitary Gland cytology, Rats, Thymidine, Thyroidectomy, Time Factors, Tritium, Pituitary Gland drug effects, Prolactin metabolism, Thyrotropin metabolism, Thyrotropin-Releasing Hormone pharmacology
Published
1973
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