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Autor

  • Smales, Glen Jacob (14)
  • Pauw, Brian Richard (8)
  • Kulak, A. (2)
  • Schnepp, Z. (2)
  • Schönhals, Andreas (2)
  • Thünemann, Andreas F. (2)
  • Alentiev, D. (1)
  • Bekheet, M. F. (1)
  • Bermeshev, M. (1)
  • Blackburn, E. (1)
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Erscheinungsjahr

  • 2020 (8)
  • 2019 (5)
  • 2018 (1)

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  • Zeitschriftenartikel (9)
  • Vortrag (2)
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Referierte Publikation

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Schlagworte

  • SAXS (6)
  • Small-angle scattering (4)
  • 266nm (1)
  • 3D printing (1)
  • Abasic site (1)
  • Advanced calorimetry (1)
  • Ag (1)
  • Agarose gel electrophorese (1)
  • Au (1)
  • Broadband Dielectric Spectrscopy (1)
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Organisationseinheit der BAM

  • 6 Materialchemie (14)
  • 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (14)
  • 6.6 Physik und chemische Analytik der Polymere (3)
  • 1 Analytische Chemie; Referenzmaterialien (1)
  • 1.2 Biophotonik (1)
  • 7 Bauwerkssicherheit (1)
  • 7.5 Technische Eigenschaften von Polymerwerkstoffen (1)

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Ectoine interaction with DNA: Influence on ultraviolet radiation damage (2020)
Hahn, Marc Benjamin ; Smales, Glen Jacob ; Seitz, H. ; Solomun, Tihomir ; Sturm, Heinz
Ectoine is a small zwitterionic osmolyte and compatible solute, which does not interfere with cell metabolism even at molar concentrations. Plasmid DNA (pUC19) was irradiated with ultraviolet radiation (UV-C at 266 nm) under quasi physiological conditions (PBS) and in pure water in the presence and absence of ectoine (THP(B)) and hydroxyectoine (THP(A)). Different types of UV induced DNA damage were analysed: DNA single-strand breaks (SSBs), abasic sites and cyclobutane pyrimidine dimers (CPDs). A complex interplay between these factors was observed with respect to the nature and occurrence of DNA damage with 266 nm photons. In PBS, the cosolutes showed efficient protection against base damage, whilst in pure water, a dramatic shift from SSB damage to base damage was observed when cosolutes were added. To test whether these effects are caused by ectoine binding to DNA, further experiments were conducted: small-angle X-ray scattering (SAXS), surface-plasmon resonance (SPR) measurements and Raman spectroscopy. The results show, for the first time, a close interaction between ectoine and DNA. This is in stark contrast to the assumption made by preferential exclusion models, which are often used to interpret the behaviour of compatible solutes within cells and with biomolecules. It is tentatively proposed that the alterations of UV damage to DNA are attributed to ectoine influence on nucleobases through the direct interaction between ectoine and DNA.
Grafting and stabilization of ordered mesoporous silica COK-12 with graphene oxide for enhanced removal of methylene blue (2019)
Henning, L. M. ; Simon, U. ; Gurlo, A. ; Smales, Glen Jacob ; Bekheet, M. F.
Large-pore ordered mesoporous silica (OMS) COK-12, analogous to the well-known SBA-15, but synthesized in a more environmentally friendly way and exhibiting a shorter plate-like structure, was grafted with different amounts of graphene oxide (GO) for the first time in an inexpensive and rapid process, that was successfully upscaled. Samples were examined with nitrogen sorption analysis, SAXS, Raman spectroscopy, XPS, and zeta potential analysis. Adsorption experiments with the cationic dye methylene blue (MB) were conducted on the grafted materials and on pure COK-12, taking into account the influence of initial dye concentration (30–600 mg L-1), adsorbent dosage (0.2–14 g L-1), contact time (0.3–300 min), solution pH (4 10), and influence of salts and temperature (0–1 M NaCl, 80 C) to simulate industrial dye effluent. The adsorption process was found to be represented best by the Langmuir isotherm model, i.e., adsorption is a monolayer process. The calculated maximum Adsorption capacities were found to be 20.2 and 197.5 mg g-1 at dosages of 5 and 0.5 g L-1 for pure COK-12 and COK-12 grafted with 50 wt% GO, respectively, at pH 5.65 and MB concentration of 100 mg L-1. Adsorption kinetics were found to follow the pseudo-second order model, i.e., chemisorption is the rate controlling step. The adsorption performances could be well preserved at simulated dye effluent. Desorption was found to be most effective with hydrochloric acid. The COK-12 grafted with GO presented in this work shows superior adsorption properties in comparison to other grafted OMS materials. In addition, grafting with GO remarkably improved the stability of COK-12 in aqueous solution.
THE MAUS: A GI-/ULTRA-/W/SAXS Instrument of the future (2018)
Smales, Glen Jacob
The Multi-scale Analyzer for Ultrafine Structures or the “MAUS” for short, is a SAXS instrument that combines a multitude of features that make it both unique, and one of the most adaptable instruments around.
Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation (2020)
Kolmangady, Mohamed ; Szynomiak, Paulina ; Smales, Glen Jacob ; Alentiev, D. ; Bermeshev, M. ; Böhning, Martin ; Schönhals, Andreas
For the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using Fast Scanning Calorimetry employing both fast heating and cooling rates. This is complimented with scattering experiments that show how the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with -Si(OR)3 side groups, which is interpreted in terms of a percolation model.
Extending SAXS instrument ranges through addition of a portable, inexpensive USAXS module (2019)
Pauw, Brian Richard ; Smith, A. J. ; Snow, T. ; Shebanova, O. ; Sutter, J. P. ; Hermida-Merino, D. ; Smales, Glen Jacob ; Terrill, N. J. ; Thünemann, Andreas F. ; Bras, W.
Ultra-SAXS can enhance the capabilities of existing SAXS/WAXS beamlines and laboratory instruments. A compact Ultra-SAXS module has been developed, which extends the measurable q-range with 0:0015 < q 1/nm) < 0:2, allowing structural dimensions between 30 < D(nm) < 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements.
Introduction to SAXS (2020)
Smales, Glen Jacob
A simplified introductions to small-angle scattering (SAXS), to put across the main concepts and not get bogged down in equations.
The SPONGE (2020)
Pauw, Brian Richard ; Smales, Glen Jacob
This software tool is intended to calculate X-ray scattering patterns from 3D objects described by an STL file. The fundamentals and use example(s) are shown.
Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement (2019)
Yildirim, Arda ; Sentker, K. ; Smales, Glen Jacob ; Pauw, Brian Richard ; Huber, P. ; Schönhals, Andreas
The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLC under cylindrical nanoconfinement is studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), where cylindrical nanoconfinement is established through embedding HAT6 into the nanopores of anodic aluminum oxide membranes (AAO), and a silica membrane with pore diameters ranging from 161 nm down to 12 nm. Both unmodified and modified pore walls were considered, and in the latter case the pore walls of AAO membranes were chemical treated with n octadecylphosphonic acid (ODPA) resulting in the formation of a 2.2 nm thick layer of grafted alkyl chains. Phase transition enthalpies decrease with decreasing pore size, indicating that a large proportion of the HAT6 molecules within the pores has a disordered structure, which increases with decreasing pore size for both pore walls. In the case of the ODPA modification the amount of ordered HAT6 is increased compared to the unmodified case. The pore size dependencies of the phase transition temperatures were approximated using the Gibbs Thomson equation, where the estimated surface tension is dependent on the molecular ordering of HAT6 molecules within the pores and upon their surface. DS was employed to investigate the molecular ordering of HAT6 within the nanopores. These investigations revealed that with a pore size of around 38 nm, for the samples with the unmodified pore walls, the molecular ordering changes from planar axial to homeotropic radial. However, the planar axial configuration, which is suitable for electronic applications, can be successfully preserved through ODPA modification for most of the pore sizes.
Complete set of raw and processed datasets, as well as associated Jupyter notebooks for analysis, associated with manuscript entitled: "The MOUSE project: a practical approach for obtaining traceable, wide-range X-ray scattering information" (2020)
Pauw, Brian Richard ; Smales, Glen Jacob
This dataset is a complete set of raw, processed and analyzed data, complete with Jupiter notebooks, associated with the manuscript mentioned in the title. In the manuscript, we provide a "systems architecture"-like overview and detailed discussions of the methodological and instrumental components that, together, comprise the "MOUSE" project (Methodology Optimization for Ultrafine Structure Exploration). Through this project, we aim to provide a comprehensive methodology for obtaining the highest quality X-ray scattering information (at small and wide angles) from measurements on materials science samples.
A π-conjugated, covalent phosphinine framework (2019)
Huang, J. ; Tarábek, J. ; Kulkarni, R. ; Wang, Cui ; Dračínský, M. ; Smales, Glen Jacob ; Pauw, Brian Richard ; Resch-Genger, Ute ; Bojdys, M. J.
Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si and S have found their way into their building blocks so far. Here, we expand the toolbox available to polymer and materials chemists by one additional nonmetal, phosphorus. Starting with a building block that contains a λ⁵‐phosphinine (C₅P) moiety, we evaluate a number of polymerisation protocols, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) via Suzuki‐Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m2 g‐1 N2 BET at 77 K) with green fluorescence (λmax 546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h‐¹ g‐¹. Our results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties that might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis.
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