Terahertz wave transmission in flexible polystyrene-lined hollow metallic waveguides for the 2.5-5 THz band.

A low-loss and low-dispersive optical-fiber-like hybrid HE11 mode is developed within a wide band in metallic hollow waveguides if their inner walls are coated with a thin dielectric layer. We investigate terahertz (THz) transmission losses from 0.5 to 5.5 THz and bending losses at 2.85 THz in a polystyrene-lined silver waveguides with core diameters small enough (1 mm) to minimize the number of undesired modes and to make the waveguide flexible, while keeping the transmission loss of the HE11 mode low. The experimentally measured loss is below 10 dB/m for 2 < ? < 2.85 THz (∼4-4.5 dB/m at 2.85 THz) and it is estimated to be below 3 dB/m for 3 < ? < 5 THz according to the numerical calculations. At ∼1.25 THz, the waveguide shows an absorption peak of ∼75 dB/m related to the transition between the TM11-like mode and the HE11 mode. Numerical modeling reproduces the measured absorption spectrum but underestimates the losses at the absorption peak, suggesting imperfections in the waveguide walls and that the losses can be reduced further. © 2013 Optical Society of America

Observation of a topologically non-trivial surface state in half-Heusler PtLuSb (001) thin films.

The discovery of topological insulators, materials with bulk band gaps and protected cross-gap surface states in compounds such as Bi2Se3, has generated much interest in identifying topological surface states (TSSs) in other classes of materials. In particular, recent theoretical calculations suggest that TSSs may be found in half-Heusler ternary compounds. If experimentally realizable, this would provide a materials platform for entirely new heterostructure spintronic devices that make use of the structurally identical but electronically varied nature of Heusler compounds. Here we show the presence of a TSS in epitaxially grown thin films of the half-Heusler compound PtLuSb. Spin- and angle-resolved photoemission spectroscopy, complemented by theoretical calculations, reveals a surface state with linear dispersion and a helical tangential spin texture consistent with previous predictions. This experimental verification of topological behaviour is a significant step forward in establishing half-Heusler compounds as a viable material system for future spintronic devices

Investigation of hollow cylindrical metal terahertz waveguides suitable for cryogenic environments

The field of terahertz (THz) waveguides continues to grow rapidly, with many being tailored to suit the specific demands of a particular final application. Here, we explore waveguides capable of enabling efficient and accurate power delivery within cryogenic environments (< 4 K). The performance of extruded hollow cylindrical metal waveguides made of un-annealed and annealed copper, as well as stainless steel, have been investigated for bore diameters between 1.75 - 4.6 mm, and at frequencies of 2.0, 2.85 and 3.4 THz, provided by a suitable selection of THz quantum cascade lasers. The annealed copper resulted in the lowest transmission losses, < 3 dB/m for a 4.6 mm diameter waveguide, along with 90° bending losses as low as ~2 dB for a bend radius of 15.9 mm. The observed trends in losses were subsequently analyzed and related to measured inner surface roughness parameters. These results provide a foundation for the development of a wide array of demanding low-temperature THz applications, and enabling the study of fundamental physics.Engineering and Physical Sciences Research Council (Grant No. EP/J017671/1, Coherent Terahertz Systems)

Paclitaxel and CYC3, an aurora kinase A inhibitor, synergise in pancreatic cancer cells but not bone marrow precursor cells.

BACKGROUND: Amplification of aurora kinase A (AK-A) overrides the mitotic spindle assembly checkpoint, inducing resistance to taxanes. RNA interference targeting AK-A in human pancreatic cancer cell lines enhanced taxane chemosensitivity. In this study, a novel AK-A inhibitor, CYC3, was investigated in pancreatic cancer cell lines, in combination with paclitaxel. METHODS: Western blot, flow cytometry and immunostaining were used to investigate the specificity of CYC3. Sulforhodamine B staining, time-lapse microscopy and colony-formation assays were employed to evaluate the cytotoxic effect of CYC3 and paclitaxel. Human colony-forming unit of granulocyte and macrophage (CFU-GM) cells were used to compare the effect in tumour and normal tissue. RESULTS: CYC3 was shown to be a specific AK-A inhibitor. Three nanomolar paclitaxel (growth inhibition 50% (GI(50)) 3 nM in PANC-1, 5.1 nM in MIA PaCa-2) in combination with 1 μM CYC3 (GI(50) 1.1 μM in MIA PaCa2 and 2 μM in PANC-1) was synergistic in inhibiting pancreatic cell growth and causing mitotic arrest, achieving similar effects to 10-fold higher concentrations of paclitaxel (30 nM). In CFU-GM cells, the effect of the combination was simply additive, displaying significantly less myelotoxicity compared with high concentrations of paclitaxel (30 nM; 60-70% vs 100% inhibition). CONCLUSION: The combination of lower doses of paclitaxel and CYC3 merits further investigation with the potential for an improved therapeutic index in vivo

Programmed DNA destruction by miniature CRISPR-Cas14 enzymes.

CRISPR-Cas systems provide microbes with adaptive immunity to infectious nucleic acids and are widely employed as genome editing tools. These tools use RNA-guided Cas proteins whose large size (950 to 1400 amino acids) has been considered essential to their specific DNA- or RNA-targeting activities. Here we present a set of CRISPR-Cas systems from uncultivated archaea that contain Cas14, a family of exceptionally compact RNA-guided nucleases (400 to 700 amino acids). Despite their small size, Cas14 proteins are capable of targeted single-stranded DNA (ssDNA) cleavage without restrictive sequence requirements. Moreover, target recognition by Cas14 triggers nonspecific cutting of ssDNA molecules, an activity that enables high-fidelity single-nucleotide polymorphism genotyping (Cas14-DETECTR). Metagenomic data show that multiple CRISPR-Cas14 systems evolved independently and suggest a potential evolutionary origin of single-effector CRISPR-based adaptive immunity

Aligning author-supplied keywords for ETDs with domain-specific controlled vocabularies

Subject access can provide essential points of access for users to find, identify, select, and obtain various resources available in libraries. Subject access is not always available, however, due to the increasing amount of metadata created by non-catalogers (including author-supplied metadata), changes in libraries’ discovery services, and a lack of best practices for aligning non-controlled vocabularies to authorized subject headings. This paper addresses the issue of author-supplied metadata, specifically how to align keywords submitted by authors of electronic theses and dissertations (ETDs) with Library of Congress Subject Headings (LCSH) and discipline-specific taxonomies by analyzing 32,696 keywords from 5,365 master's theses and doctoral dissertations submitted to the University of Illinois at Urbana-Champaign's institutional repository between 2010 and 2014. This paper shares findings from the data analysis, including that matching rates vary depending on college, with newer or rapidly-developing fields (such as the School of Molecular and Cellular Biology) having lower matching rates than traditional, well-established fields of study (such as the College of Agriculture, Consumer, and Environmental Sciences), and recommends that when keyword reconciliation is performed, it should be done with more than one authority in tandem for the best results; when the LCSH and discipline-specific controlled vocabularies were combined, matching results were slightly or moderately increased.Ope

When benefit eligibility and patient-led care intersect. Living in the UK with chronic illness:Experiences of the work capability assessment

Individuals living with chronic physical health conditions are more likely to be out-of-work than other groups. Often framed as a 'response' to these statistics, many countries have introduced policy instruments for promoting the employment of individuals with chronic conditions. This qualitative study sought to explore the impact of welfare reforms on UK individuals. Employing a phenomenological approach, semi-structured interviews were conducted with five participants living with chronic conditions. Three themes were generated using Interpretative Phenomenological Analysis: 'intersubjective sense making of the condition'; 'battles for control' and 'the fluidity and strengthening of identity'. Implications for further, holistic, policy reform are explored

Mathematical imaging methods for mitosis analysis in live-cell phase contrast microscopy

In this paper we propose a workflow to detect and track mitotic cells in time-lapse microscopy image sequences. In order to avoid the requirement for cell lines expressing fluorescent markers and the associated phototoxicity, phase contrast microscopy is often preferred over fluorescence microscopy in live-cell imaging. However, common specific image characteristics complicate image processing and impede use of standard methods. Nevertheless, automated analysis is desirable due to manual analysis being subjective, biased and extremely time-consuming for large data sets. Here, we present the following workflow based on mathematical imaging methods. In the first step, mitosis detection is performed by means of the circular Hough transform. The obtained circular contour subsequently serves as an initialisation for the tracking algorithm based on variational methods. It is sub-divided into two parts: in order to determine the beginning of the whole mitosis cycle, a backwards tracking procedure is performed. After that, the cell is tracked forwards in time until the end of mitosis. As a result, the average of mitosis duration and ratios of different cell fates (cell death, no division, division into two or more daughter cells) can be measured and statistics on cell morphologies can be obtained. All of the tools are featured in the user-friendly MATLAB®Graphical User Interface MitosisAnalyser.JSG acknowledges support by the NIHR Cambridge Biomedical Research Centre and would like to thank Hendrik Dirks, Fjedor Gaede [45] and Jonas Geiping [46] for fruitful discussions in the context of a practical course at WWU Münster in 2014 and significant speed-up and GPU implementation of earlier versions of the code. JSG and MB would like to thank Michael Möller for providing the basic tracking code and acknowledge support by ERC via Grant EU FP 7 - ERC Consolidator Grant 615216 LifeInverse. MB acknowledges further support by the German Science Foundation DFG via Cells-in-Motion Cluster of Excellence. CBS acknowledges support from the EPSRC grant Nr. EP/M00483X/1, from the Leverhulme grant “Breaking the non-convexity barrier”, from the EPSRC Centre for Mathematical And Statistical Analysis Of Multimodal Clinical Imaging grant Nr. EP/N014588/1, and the Cantab Capital Institute for the Mathematics of Information. JAH, SBK, JAP, AS and SR were funded by Cancer Research UK, The University of Cambridge and Hutchison Whampoa Ltd. SBK also received funding from Pancreatic Cancer UK