X-ray tomography data of compression tested unidirectional fibre composites with different off-axis angles

This data article contains lab-based micro-computed tomography (μCT) data of unidirectional (UD) non-crimp fabric (NCF) carbon fibre reinforced composite specimens that have been deformed by compression. The specimens contain UD fibres with off-axis angles of 0\ub0, 5\ub0, 10\ub0, 15\ub0 and 20\ub0 and the compression testing induces kink-band formation. This data formed the basis for the analysis of the influence of in-plane shear on kink-plane orientation as reported in Wilhelmsson et al. (Wilhelmsson et al., 2019)

Highly efficient incorporation of the fluorescent nucleotide analogs tC and tCO by Klenow fragment

Studies of the mechanisms by which DNA polymerases select the correct nucleotide frequently employ fluorescently labeled DNA to monitor conformational rearrangements of the polymerase–DNA complex in response to incoming nucleotides. For this purpose, fluorescent base analogs play an increasingly important role because they interfere less with the DNA–protein interaction than do tethered fluorophores. Here we report the incorporation of the 5′-triphosphates of two exceptionally bright cytosine analogs, 1,3-diaza-2-oxo-phenothiazine (tC) and its oxo-homolog, 1,3-diaza-2-oxo-phenoxazine (tCO), into DNA by the Klenow fragment. Both nucleotide analogs are polymerized with slightly higher efficiency opposite guanine than cytosine triphosphate and are shown to bind with nanomolar affinity to the DNA polymerase active site, according to fluorescence anisotropy measurements. Using this method, we perform competitive binding experiments and show that they can be used to determine the dissociation constant of any given natural or unnatural nucleotide. The results demonstrate that the active site of the Klenow fragment is flexible enough to tolerate base pairs that are size-expanded in the major groove. In addition, the possibility to enzymatically polymerize a fluorescent nucleotide with high efficiency complements the tool box of biophysical probes available to study DNA replication

A novel wear-resistant magnetic thin film material based on a Ti1−xFexC1−yTi_{1-x}Fe_xC_{1-y} nanocomposite alloy

In this study we report on the film growth and characterization of thin (approximately 50 nm thick) Ti-Fe-C films deposited on amorphous quartz. The experimental studies have been complemented by first principles density functional theory (DFT) calculations. Upon annealing of as-prepared films, the composition of the metastable Ti-Fe-C film changes. An iron-rich phase is first formed close to the film surface, but with increasing annealing time this phase is gradually displaced toward the film-substrate interface where its position stabilizes. Both the magnetic ordering temperature and the saturation magnetization changes significantly upon annealing. The DFT calculations show that the critical temperature and the magnetic moment both increase with increasing Fe and C-vacancy concentration. The formation of the metastable iron-rich Ti-Fe-C compound is reflected in the strong increase of the magnetic ordering temperature. Eventually, after enough annealing time ($\geq 10$ minutes), nano-crystalline $\alpha$-Fe starts to precipitate and the amount and size of these precipitates can be controlled by the annealing procedure; after 20 minutes of annealing, the experimental results indicate a nano-crystalline iron-film embedded in a wear resistant TiC compound. This conclusion is further supported by transmission electron microscopy studies on epitaxial Ti-Fe-C films deposited on single crystalline MgO substrates where, upon annealing, an iron film embedded in TiC is formed. Our results suggest that annealing of metastable Ti-Fe-C films can be used as an efficient way of creating a wear-resistant magnetic thin film material.Comment: 23 pages, 13 figure

Electronic structure and chemical bonding in Ti4SiC3 investigated by soft x-ray emission spectroscopy and first principle theory

The electronic structure in the new transition metal carbide Ti4SiC3 has been investigated by bulk-sensitive soft x-ray emission spectroscopy and compared to the well-studied Ti3SiC2 and TiC systems. The measured high-resolution Ti L, C K and Si L x-ray emission spectra are discussed with ab initio calculations based on density-functional theory including core-to-valence dipole matrix elements. The detailed investigations of the Ti-C and Ti-Si chemical bonds provide increased understanding of the physical properties of these nanolaminates. A strongly modified spectral shape is detected for the buried Si monolayers due to Si 3p hybridization with the Ti 3d orbitals. As a result of relaxation of the crystal structure and the charge-transfer from Ti (and Si) to C, the strength of the Ti-C covalent bond is increased. The differences between the electronic and crystal structures of Ti4SiC3 and Ti3SiC2 are discussed in relation to the number of Si layers per Ti layer in the two systems and the corresponding change of materials properties.Comment: 12 pages, 7 figures, 1 tabl

Carbon release by selective alloying of transition metal carbides

We have performed first principles density functional theory calculations on TiC alloyed on the Ti sublattice with 3d transition metals ranging from Sc to Zn. The theory is accompanied with experimental investigations, both as regards materials synthesis as well as characterization. Our results show that by dissolving a metal with a weak ability to form carbides, the stability of the alloy is lowered and a driving force for the release of carbon from the carbide is created. During thin film growth of a metal carbide this effect will favor the formation of a nanocomposite with carbide grains in a carbon matrix. The choice of alloying elements as well as their concentrations will affect the relative amount of carbon in the carbide and in the carbon matrix. This can be used to design the structure of nanocomposites and their physical and chemical properties. One example of applications is as low-friction coatings. Of the materials studied, we suggest the late 3d transition metals as the most promising elements for this phenomenon, at least when alloying with TiC.Comment: 9 pages, 6 figure

Understanding and protecting vulnerable financial consumers

This article considers how consumer protection law and policy should address the interests of particularly vulnerable financial consumers. Specifically, the article proposes a taxonomy of vulnerability which helps to identify (a) what makes consumers particularly vulnerable, and (b) how consumer protection law and consumer policy (broadly understood) can respond to these causes in a way that provides such consumers with appropriate protection. Changes to economic conditions, legal requirements on traders and our understanding of consumer behaviour make discussion of these issues particularly topical. There is little doubt that finding solutions is extremely difficult. Trade-offs are necessary and some enduring factors that contribute to vulnerability, in particular poverty, sometimes appear intractable. Nevertheless, it is submitted that by identifying clearly both why consumers are vulnerable and how the factors that lead to such vulnerability can be addressed, it is possible to construct an environment which respects consumer choice while ensuring that the most vulnerable are protected appropriately

Electronic structure investigation of Ti3AlC2, Ti3SiC2, and Ti3GeC2 by soft-X-ray emission spectroscopy

The electronic structures of epitaxially grown films of Ti3AlC2, Ti3SiC2 and Ti3GeC2 have been investigated by bulk-sensitive soft X-ray emission spectroscopy. The measured high-resolution Ti L, C K, Al L, Si L and Ge M emission spectra are compared with ab initio density-functional theory including core-to-valence dipole matrix elements. A qualitative agreement between experiment and theory is obtained. A weak covalent Ti-Al bond is manifested by a pronounced shoulder in the Ti L-emission of Ti3AlC2. As Al is replaced with Si or Ge, the shoulder disappears. For the buried Al and Si-layers, strongly hybridized spectral shapes are detected in Ti3AlC2 and Ti3SiC2, respectively. As a result of relaxation of the crystal structure and the increased charge-transfer from Ti to C, the Ti-C bonding is strengthened. The differences between the electronic structures are discussed in relation to the bonding in the nanolaminates and the corresponding change of materials properties.Comment: 15 pages, 8 figure

Ti3SiC2-formation during Ti–C–Si multilayer deposition by magnetron sputtering at 650 °C

Titanium Silicon Carbide films were deposited from three separate magnetrons with elemental targets onto Si wafer substrates. The substrate was moved in a circular motion such that the substrate faces each magnetron in turn and only one atomic species (Ti, Si or C) is deposited at a time. This allows layer-by-layer film deposition. Material average composition was determined to Ti0.47Si0.14C0.39 by energy-dispersive X-ray spectroscopy. High-resolution transmission electron microscopy and Raman spectroscopy were used to gain insights into thin film atomic structure arrangements. Using this new deposition technique formation of Ti3SiC2 MAX phase was obtained at a deposition temperature of 650 °C, while at lower temperatures only silicides and carbides are formed. Significant sharpening of Raman E2g and Ag peaks associated with Ti3SiC2 formation was observed

Pulse-shaped two-photon excitation of a fluorescent base analogue approaches single-molecule sensitivity

Fluorescent nucleobase analogues (FBAs) have many desirable features in comparison to extrinsic fluorescent labels, but they are yet to find application in ultrasensitive detection. Many of the disadvantages of FBAs arise from their short excitation wavelengths (often in the ultraviolet), making two-photon excitation a potentially attractive approach. Pentacyclic adenine (pA) is a recently developed FBA that has an exceptionally high two-photon brightness. We have studied the two-photon-excited fluorescence properties of pA and how they are affected by incorporation in DNA. We find that pA is more photostable under two-photon excitation than via resonant absorption. When incorporated in an oligonucleotide, pA has a high two-photon cross section and emission quantum yield, varying with sequence context, resulting in the highest reported brightness for such a probe. The use of a two-photon microscope with ultrafast excitation and pulse shaping has allowed the detection of pA-containing oligonucleotides in solution with a limit of detection of ∼5 molecules, demonstrating that practical single-molecule detection of FBAs is now within reach