TY - JOUR A1 - Tran, Thanh Ngoc A1 - Kreißig, R. A1 - Staat, Manfred T1 - Probabilistic limit and shakedown analysis of thin plates and shells JF - Structural safety. 31 (2009), H. 1 Y1 - 2009 SN - 0167-4730 SP - 1 EP - 18 PB - - ER - TY - JOUR A1 - Bassam, Rasha A1 - Hescheler, Jürgen A1 - Temiz Artmann, Aysegül A1 - Artmann, Gerhard A1 - Digel, Ilya T1 - Effects of spermine NONOate and ATP on the thermal stability of hemoglobin JF - BMC Biophysics N2 - Background Minor changes in protein structure induced by small organic and inorganic molecules can result in significant metabolic effects. The effects can be even more profound if the molecular players are chemically active and present in the cell in considerable amounts. The aim of our study was to investigate effects of a nitric oxide donor (spermine NONOate), ATP and sodium/potassium environment on the dynamics of thermal unfolding of human hemoglobin (Hb). The effect of these molecules was examined by means of circular dichroism spectrometry (CD) in the temperature range between 25°C and 70°C. The alpha-helical content of buffered hemoglobin samples (0.1 mg/ml) was estimated via ellipticity change measurements at a heating rate of 1°C/min. Results Major results were: 1) spermine NONOate persistently decreased the hemoglobin unfolding temperature T u irrespectively of the Na + /K + environment, 2) ATP instead increased the unfolding temperature by 3°C in both sodium-based and potassium-based buffers and 3) mutual effects of ATP and NO were strongly influenced by particular buffer ionic compositions. Moreover, the presence of potassium facilitated a partial unfolding of alpha-helical structures even at room temperature. Conclusion The obtained data might shed more light on molecular mechanisms and biophysics involved in the regulation of protein activity by small solutes in the cell. KW - Nitric Oxide Donor KW - NONOate KW - Circular Dichroism KW - Nitric Oxide Y1 - 2012 U6 - https://doi.org/10.1186/2046-1682-5-16 SN - 2046-1682 VL - 5 PB - BioMed Central CY - London ER - TY - JOUR A1 - Mansurov, Z. A1 - Digel, Ilya A1 - Biisenbaev, M. A1 - Savistkaya, I. A1 - Kistaubaeva, A. A1 - Akimbekov, Nuraly S. A1 - Zhubanova, A. T1 - Bio-composite material on the basis of carbonized rice husk in biomedicine and environmental applications JF - Eurasian Chemico-Technological Journal Y1 - 2012 U6 - https://doi.org/10.18321/ectj105 SN - 2522-4867 VL - 14 IS - 2 SP - 115 EP - 131 PB - Institute of Combustion Problems CY - Almaty ER - TY - JOUR A1 - Staat, Manfred A1 - Tran, Thanh Ngoc A1 - Kreißig, R. T1 - Load bearing capacity of thin shell structures made of elastoplastic material by direct methods JF - Technische Mechanik. 28 (2008), H. 3-4 Y1 - 2008 SP - 299 EP - 309 ER - TY - JOUR A1 - Staat, Manfred A1 - Ballmann, J. T1 - Wave Propagation and Focussing in Plates JF - Impact loading and dynamic behaviour of materials : Papers presented at the International Conference on Impact Loading and Dynamic Behaviour of Materials, Vol. 2 / Chiem, C. Y.; Kunze, L. (u.a.) [eds] Y1 - 1988 PB - DGM Informationsges. CY - Oberursel ER - TY - JOUR A1 - Tran, Thanh Ngoc A1 - Pham, Phu Tinh A1 - Vu, D. K. A1 - Staat, Manfred T1 - Reliability Analysis of Inelastic Shell Structures Under Variable Loads JF - Limit States of Materials and Structures : Direct Methods / Hrsg. Dieter Weichert; Hrsg. Alan Ponter Y1 - 2009 SN - 978-1-4020-9633-4 SP - 135 EP - 156 PB - Springer Netherland CY - Berlin ER - TY - JOUR A1 - Laack, Walter van T1 - The genetic code should be seen as a positioning code JF - British journal of arts and social sciences. Vol. 14 (2013), No. 1 Y1 - 2013 SN - 2046-9578 SP - 93 EP - 97 ER - TY - CHAP A1 - Staat, Manfred A1 - Heitzer, Michael T1 - The restricted influence of kinematic hardening on shakedown loads N2 - Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model. KW - Biomedizinische Technik KW - Einspielen KW - Shakedown KW - Ratcheting KW - Bruchmechanik KW - shakedown KW - material shakedown KW - linear kinematic hardening KW - nonlinear kinematic hardening KW - ratchetting Y1 - 2002 ER - TY - CHAP A1 - Osterhage, Hannes A1 - Bialonski, Stephan A1 - Staniek, Matthäus A1 - Schindler, Kaspar A1 - Wagner, Tobias A1 - Elger, Christian E. A1 - Lehnertz, Klaus T1 - Bivariate and multivariate time series analysis techniques and their potential impact for seizure prediction T2 - Seizure Prediction in Epilepsy: From Basic Mechanisms to Clinical Applications Y1 - 2008 SN - 978-3-527-62519-2 U6 - https://doi.org/10.1002/9783527625192.ch15 SP - 189 EP - 208 PB - Wiley-VCH CY - Weinheim ER - TY - GEN A1 - Staat, Manfred T1 - Engineering Mechanics. Lecture Notes. 2nd edition, translation of the 3rd corrected and extended German edition of "Technische Mechanik" N2 - English translation of the corrected lectures notes of Sebastian Krämer. Contents 0 Introduction to Mechanics 1 Statics of Rigid Bodies 2 Elastostatics (Strength of Materials) 3 Kinematics 4 Kinetics Literature KW - Technische Mechanik KW - Mechanics KW - Statics KW - Elastostatics KW - Kinematics KW - Kinetics Y1 - 2006 ER - TY - CHAP A1 - Staat, Manfred T1 - Problems and chances for probabilistic fracture mechanics in the analysis of steel pressure boundary reliability. - Überarb. Ausg. N2 - In: Technical feasibility and reliability of passive safety systems for nuclear power plants. Proceedings of an Advisory Group Meeting held in Jülich, 21-24 November 1994. - Vienna , 1996. - Seite: 43 - 55 IAEA-TECDOC-920 Abstract: It is shown that the difficulty for probabilistic fracture mechanics (PFM) is the general problem of the high reliability of a small population. There is no way around the problem as yet. Therefore what PFM can contribute to the reliability of steel pressure boundaries is demon­strated with the example of a typical reactor pressure vessel and critically discussed. Although no method is distinguishable that could give exact failure probabilities, PFM has several addi­tional chances. Upper limits for failure probability may be obtained together with trends for design and operating conditions. Further, PFM can identify the most sensitive parameters, improved control of which would increase reliability. Thus PFM should play a vital role in the analysis of steel pressure boundaries despite all shortcomings. KW - Bruchmechanik KW - probabilistic fracture mechanics KW - PFM Y1 - 2006 ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred A1 - Kreißig, R. T1 - Calculation of load carrying capacity of shell structures with elasto-plastic material by direct methods N2 - Proceedings of the International Conference on Material Theory and Nonlinear Dynamics. MatDyn. Hanoi, Vietnam, Sept. 24-26, 2007, 8 p. In this paper, a method is introduced to determine the limit load of general shells using the finite element method. The method is based on an upper bound limit and shakedown analysis with elastic-perfectly plastic material model. A non-linear constrained optimisation problem is solved by using Newton’s method in conjunction with a penalty method and the Lagrangean dual method. Numerical investigation of a pipe bend subjected to bending moments proves the effectiveness of the algorithm. KW - Finite-Elemente-Methode Y1 - 2007 ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Structural Reliability Analysis of Elasto-Plastic Structures JF - Safety and reliability : proceedings of ESREL '99, the Tenth European Conference on Safety and Reliability, Munich-Garching, Germany, 13 - 17 September 1999 / Schuëller, G. I.; Kafka, P. [eds] Y1 - 1999 SN - 90-5809-109-0 SP - 513 EP - 518 PB - Balkema CY - Rotterdam ER - TY - CHAP A1 - Tran, Thanh Ngoc A1 - Novacek, V. A1 - Tolba, R. A1 - Klinge, U. A1 - Turquier, F. A1 - Staat, Manfred T1 - Experimental and Computational approach to study colorectal anastomosis. ISB2011, Proceedings of the XXIII Congress of the International Society of Biomechanics, Brussels, Belgium, July 3-7, 2011 N2 - Summary: This paper presents a methodology to study and understand the mechanics of stapled anastomotic behaviors by combining empirical experimentation and finite element analysis. Performance of stapled anastomosis is studied in terms of leakage and numerical results which are compared to in vitro experiments performed on fresh porcine tissue. Results suggest that leaks occur between the tissue and staple legs penetrating through the tissue. KW - Anastomose KW - Finite-Elemente-Methode KW - Biomechanik KW - Anastomosis KW - Finite element method KW - Biomechanics Y1 - 2011 ER - TY - JOUR A1 - Kleefeld, Andreas A1 - Reißel, Martin T1 - The Levenberg–Marquardt method applied to a parameter estimation problem arising from electrical resistivity tomography JF - Applied Mathematics and Computation Y1 - 2011 SN - 0096-3003 VL - 217 IS - 9 SP - 4490 EP - 4501 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Staat, Manfred T1 - FEM shakedown analysis of Kirchhoff-Love plates under uncertainty of strength T2 - Proceedings of UNCECOMP 2021 N2 - A new formulation to calculate the shakedown limit load of Kirchhoff plates under stochastic conditions of strength is developed. Direct structural reliability design by chance con-strained programming is based on the prescribed failure probabilities, which is an effective approach of stochastic programming if it can be formulated as an equivalent deterministic optimization problem. We restrict uncertainty to strength, the loading is still deterministic. A new formulation is derived in case of random strength with lognormal distribution. Upper bound and lower bound shakedown load factors are calculated simultaneously by a dual algorithm. Y1 - 2021 SN - 978-618-85072-6-5 U6 - https://doi.org/10.7712/120221.8041.19047 N1 - UNCECOMP 2021, 4th International Conference on Uncertainty Quantification in Computational Sciences and Engineering, streamed from Athens, Greece, 28–30 June 2021. SP - 323 EP - 338 ER - TY - JOUR A1 - Hackl, Michael A1 - Nacov, Julia A1 - Kammerlohr, Sandra A1 - Staat, Manfred A1 - Buess, Eduard A1 - Leschinger, Tim A1 - Müller, Lars P. A1 - Wegmann, Kilian T1 - Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure JF - The American Journal of Sports Medicine Y1 - 2021 U6 - https://doi.org/10.1177/03635465211006138 SN - 1552-3365 SN - 0363-5465 VL - 49 IS - 7 SP - 1847 EP - 1853 PB - Sage CY - London ER - TY - JOUR A1 - Stadler, Andreas M. A1 - Embs, Jan P. A1 - Digel, Ilya A1 - Artmann, Gerhard A1 - Unruh, Tobias A1 - Büldt, Georg A1 - Zaccai, Guiseppe T1 - Cytoplasmic water and hydration layer dynamics in human red blood cells JF - Journal of the American Chemical Society. 50 (2008), H. 130 Y1 - 2008 SN - 1520-5126 SP - 16852 EP - 16853 ER - TY - JOUR A1 - Staat, Manfred T1 - Cyclic plastic deformation tests to verify FEM-based shakedown analyses N2 - Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between the shakedown range and the ratcheting range (continuing deformation). As part of an EU-supported research project, experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube, and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis. KW - Materialermüdung KW - Einspielen KW - Materialermüdung KW - shakedown analyses KW - thermal ratcheting KW - fatigue analyses Y1 - 2001 ER - TY - JOUR A1 - Muschallik, Lukas A1 - Molinnus, Denise A1 - Jablonski, Melanie A1 - Kipp, Carina Ronja A1 - Bongaerts, Johannes A1 - Pohl, Martina A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Selmer, Thorsten A1 - Siegert, Petra T1 - Synthesis of α-hydroxy ketones and vicinal (R, R)-diols by Bacillus clausii DSM 8716ᵀ butanediol dehydrogenase JF - RSC Advances N2 - α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated. Y1 - 2020 U6 - https://doi.org/10.1039/D0RA02066D SN - 2046-2069 VL - 10 SP - 12206 EP - 12216 PB - Royal Society of Chemistry (RSC) CY - Cambridge ER -