Patrina SP Poh  Cordula Hege  Mohit P Chhaya  Elizabeth R Balmayor  Peter Foehr  Rainer H Burgkart  Jan‐Thorsten Schantz  Stefan M Schiller  Arndt F Schilling  Dietmar W Hutmacher 《Polymer International》2017,66(1):77-84

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry  相似文献   

    

Johannes Junemann  Gurbet Birgin  Jelena Erdmann  Anke Schröder  Ingo Just  Ralf Gerhard  Andreas Pich 《Proteomics. Clinical applications》2017,11(3-4)

  相似文献   

    

Sebastian Lehmann  Maike Fischer  Andreas Rosin  Thorsten Gerdes  Walter Krenkel 《International Journal of Applied Glass Science》2020,11(2):369-379

With an overall collection and recycling rate of 74%, the material cycle for glass packaging is well established in the European Union. However, knowledge of the composition of the recycled glass cullet is necessary to avoid creeping accumulation of undesirable contaminants into the material cycle. Due to their toxic properties, this applies in particular for heavy metals, for example, lead. The state-of-the-art technology for detection of lead in recycling glass sorting is X-ray fluorescence (XRF). Due to lower regulatory demands, as well as increasingly economical hardware, laser-based detection techniques, like Laser-Induced Breakdown Spectroscopy (LIBS) may provide an alternate approach in industrial glass sorting to reach comparable detection limits and rates. In our work, CO₂-LIBS was investigated as an alternative tool for the determination of lead in glass cullet. Instead of usually utilized spectrometers, a combination of spectral filters and photodiode was employed to facilitate a fast detection rate. Glass samples with different lead content were investigated in two spectral ranges with respect to detection limits, detection speed, and accuracy. The results are compared to a commercial XRF-sorting machine for glass cullet. It was found that comparable speeds and accuracies for lead detection in glasses can be reached.  相似文献   

    

Thorsten Eichler  Bernd Isecke 《工业材料与腐蚀》2020,71(5):738-748

A wide range of parameters was investigated by numerical calculations concerning their impact on DC stray current corrosion of reinforced concrete (RC) structures. A simplified model geometry was used to extract the relevant parameters and their interaction in terms of stray current-affected structures. This study mainly focuses on RC structures that are fitted with cathodic protection installations. The findings reveal a complex interaction between the investigated parameters. The possible relevance of further parameters, which is not the subject of this study, was emphasised.  相似文献   

    

Phil Opitz  Laura Besch  Martin Panthöfer  Anke Kabelitz  Ronald E. Unger  Franziska Emmerling  Mihail Mondeshki  Wolfgang Tremel 《Advanced functional materials》2021,31(3):2007830

A protein-free formation of bone-like apatite from amorphous precursors through ball-milling is reported. Mg²⁺ ions are crucial to achieve full amorphization of CaCO₃. Mg²⁺ incorporation generates defects which strongly retard a recrystallization of ball-milled Mg-doped amorphous calcium carbonate (BM-aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg-doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg²⁺ contents, BM-aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg-doped ACC forms in the presence of phosphate ions bone-like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH⁻) and type B (PO₄³⁻) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin-free material and makes BM-aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases.  相似文献   

    

Sijia Liao;Lisa Börmel;Anke Katharina Müller;Luisa Gottschalk;Nadine Pritsch;Lara Zoé Preisner;Oleksandra Samokhina;Maria Schwarz;Anna P. Kipp;Wiebke Schlörmann;Michael Glei;Martin Schubert;Lisa Schmölz;Maria Wallert;Stefan Lorkowski; 《Molecular nutrition & food research》2024,68(23):2400455

The α-tocopherol long-chain metabolite α-tocopherol-13′-hydroxy-chromanol (α-T-13′-COOH) is a proposed regulatory intermediate of endogenous vitamin E metabolism. Effects of α-T-13′-COOH on cell viability and adaptive stress response are not well understood. The present study aims to investigate the concentration-dependent effects of α-T-13′-COOH on cellular redox homeostasis, genotoxicity, and cytotoxicity in murine RAW264.7 macrophages as a model system.  相似文献   

    

Sebastian M. Geier  Thorsten Mahrholz  Peter Wierach  Michael Sinapius 《国际智能与纳米材料杂志》2018,9(2):111-134

ABSTRACT

Future adaptive applications require lightweight and stiff materials with high active strain but low energy consumption. A suitable combination of these properties is offered by carbon nanotube-based actuators. Papers made of carbon nanotubes (CNTs) are charged within an electrolyte, which results in an electrical field forming a double-layer of ions at their surfaces and a deflection of the papers can be detected. Until now, there is no generally accepted theory for the actuation mechanism. This study focuses on the actuation mechanism of CNT papers, which represent architectures of randomly oriented CNTs. The samples are tested electrochemically in an in-plane set-up to detect the free strain. The elastic modulus of the CNT papers is analyzed in a tensile test facility. The influence of various ion sizes of water-based electrolytes is investigated.

During the tests, four parameters that have a significant influence on the mechanical performance of CNT papers were identified: the test conditions, the electrical charging, the microstructure and the ion size. All of these influencing factors point to the mechanically weak inter-tube linking at which the actuation seems to take place. Quadratic voltage-strain correlation suggests a combination of electrostatic and volumetric effects as the possible reason for CNT paper actuation.

Abbreviations: CNT: carbon nanotubes; CV: cyclic voltammetry; CVD: chemical vapor deposition; HiPCO: high pressure carbon monoxide; IL: ionic liquid; MWCNT: multi-walled carbon nanotube; MW: multi-walled; NHE: normal hydrogen electrode; PDMS: polydimethylsiloxane; PMMA: polymethylmethacrylate; PPy: polypyrrole; PVDF: polyvinylidenefluoride; SCE: saturated calomel electrode; SWCNT: single-walled carbon nanotube; SW: single-walled; 1M: one molar concentration  相似文献   

    

Jadran Vrabec  Martin Bernreuther  Hans‐Joachim Bungartz  Wei‐Lin Chen  Wilfried Cordes  Robin Fingerhut  Colin W. Glass  Jürgen Gmehling  René Hamburger  Manfred Heilig  Matthias Heinen  Martin T. Horsch  Chieh‐Ming Hsieh  Marco Hülsmann  Philip Jäger  Peter Klein  Sandra Knauer  Thorsten Köddermann  Andreas Köster  Kai Langenbach  Shiang‐Tai Lin  Philipp Neumann  Jürgen Rarey  Dirk Reith  Gábor Rutkai  Michael Schappals  Martin Schenk  Andre Schedemann  Mandes Schönherr  Steffen Seckler  Simon Stephan  Katrin Stöbener  Nikola Tchipev  Amer Wafai  Stephan Werth  Hans Hasse 《化学，工程师，技术》2018,90(3):295-306

This article outlines advances in molecular modeling and simulation using massively parallel high‐performance computers (HPC). In the SkaSim project, partners from the HPC community collaborated with users from science and industry. The aim was to optimize the prediction of thermodynamic property data in terms of efficiency, quality and reliability using HPC methods. In this context, various topics were dealt with: atomistic simulation of homogeneous gas bubble formation, surface tension of classical fluids and ionic liquids, multicriteria optimization of molecular models, the development of the molecular simulation codes ls1 mardyn and ms2, atomistic simulation of gas separation processes, molecular membrane structure generators, transport resistors and the evaluation of predictive property data models based on specific mixture types.  相似文献   

    

Andrej Paul  Bertram Schwind  Christian Weinberger  Michael Tiemann  Thorsten Wagner 《Advanced functional materials》2019,29(43)

A nanocomposite material based on copper(II) oxide (CuO) and its utilization as a highly selective and stable gas‐responsive electrical switch for hydrogen sulphide (H₂S) detection is presented. The material can be applied as a sensitive layer for H₂S monitoring, e.g., in biogas gas plants. CuO nanoparticles are embedded in a rigid, nanoporous silica (SiO₂) matrix to form an electrical percolating network of low conducting CuO and, upon exposure to H₂S, highly conducting copper(II) sulphide (CuS) particles. By steric hindrance due to the silica pore walls, the structure of the network is maintained even though the reversible reaction of CuO to CuS is accompanied by significant volume expansion. The conducting state of the percolating network can be controlled by a variety of parameters, such as temperature, electrode layout, and network topology of the porous silica matrix. The latter means that this new type of sensing material has a structure‐encoded detection limit for H₂S, which offers new application opportunities. The fabrication process of the mesoporous CuO@SiO₂ composite as well as the sensor design and characteristics are described in detail. In addition, theoretical modeling of the percolation effect by Monte‐Carlo simulations yields deeper insight into the underlying percolation mechanism and the observed response characteristics.  相似文献   

    

Thorsten Helbig  Thomas Müller  Matthias Oppe 《Stahlbau》2019,88(9):900-907

New bridge in HafenCity – pedestrian and bicycle crossing with integrated infrastructure via Baakenhafen In Hamburg, extensive infrastructure projects are being implemented as part of the revitalization of the Baakenhafen district. Besides others this includes the new central pedestrian and bicycle crossing via Baakenhafen. The slender steel bridge with a span length of 65 m is the result of a design competition sponsored by HafenCity Hamburg GmbH, won by Hamburg based architects Gerkan, Marg and Partner (gmp architects) in collaboration with the structural engineers of Knippers Helbig from Stuttgart. In addition to its function as a route connection, the bridge also serves as a logistical infrastructure construction for the sole supply of the district with the necessary energy sources and media. The completion in May 2018 was therefore an integral part of urban development within HafenCity.  相似文献