Laser-produced plasma EUV source based on tin-rich, thin-layer targets

In this paper a new approach to a laser-produced plasma EUV source based on a tin target is presented. A thin layer of pure tin and composite layers consisting of Sn with Si, SiO and LiF are investigated. The target composed of several thin layers produces less debris than the other targets and provides a conversion efficiency (CE) in the 13.5-nm +/- 1% band at least comparable to the CE for the pure tin slab target. The largest CE was observed for the target composed of a mixture of Sn and LiF, due to the fact that lithium, similarly to tin, is a strong emitter at 13.5 nm

Demonstration of an exposed-core fiber platform for two-photon rubidium spectroscopy

We demonstrate a promising fiber architecture for generating strong photon-photon interactions. Exposed-core silica optical fibers possess low-loss guidance between 400 and 1700 nm crucial for quantum-logic applications. The potential of this fiber is demonstrated by exciting a two-photon transition within a rubidium vapor using an exposed-core silica optical fiber. Transit-time broadened spectral features enable measurement of the evanescent-field scale length of (120 +/- 20) nm which shows excellent agreement with the characteristics of the modeled fiber mode (118 +/- 2) nm. We observe a two-photon absorption coefficient of 8.3 cm(-1) for one optical mode in response to a transmitted power of 1.3mW in the second mode. A clear pathway to an exposed-core fiber exhibiting substantial absorption mediated by a single photon is identified

Free Radicals, Salicylic Acid and Mycotoxins in Asparagus After Inoculation with Fusarium proliferatum and F. oxysporum

Electron paramagnetic resonance was used to monitor free radicals and paramagnetic species like Fe, Mn, Cu generation, stability and status in Asparagus officinalis infected by common pathogens Fusarium proliferatum and F. oxysporum. Occurrence of F. proliferatum and F. oxysporum, level of free radicals and other paramagnetic species, as well as salicylic acid and mycotoxins content in roots and stems of seedlings were estimated on the second and fourth week after inoculation. In the first term free and total salicylic acid contents were related to free radicals level in stem (P = 0.010 and P = 0.033, respectively). Concentration of Fe3+ ions in porphyrin complexes (g = 2.3, g = 2.9) was related to the species of pathogen. There was no significant difference between Mn2+ concentrations in stem samples; however, the level of free radicals in samples inoculated with F. proliferatum was significantly higher when compared to F. oxysporum

Elastic Properties of 4–6 nm-thick Glassy Carbon Thin Films

Glassy carbon is a disordered, nanoporous form of carbon with superior thermal and chemical stability in extreme environments. Freestanding glassy carbon specimens with 4–6 nm thickness and 0.5 nm average pore size were synthesized and fabricated from polyfurfuryl alcohol precursors. Elastic properties of the specimens were measured in situ inside a scanning electron microscope using a custom-built micro-electro-mechanical system. The Young’s modulus, fracture stress and strain values were measured to be about 62 GPa, 870 MPa and 1.3%, respectively; showing strong size effects compared to a modulus value of 30 GPa at the bulk scale. This size effect is explained on the basis of the increased significance of surface elastic properties at the nanometer length-scale

Perspective: biomedical sensing and imaging with optical fibers - innovation through convergence of science disciplines

The probing of physiological processes in living organisms is a grand challenge that requires bespoke analytical tools. Optical fiber probes offer a minimally invasive approach to report physiological signals from specific locations inside the body. This perspective article discusses a wide range of such fiber probes developed at the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics. Our fiber platforms use a range of sensing modalities, including embedded nanodiamonds for magnetometry, interferometric fiber cavities for refractive index sensing, and tailored metal coatings for surface plasmon resonance sensing. Other fiber probes exploit molecularly sensitive Raman scattering or fluorescence where optical fibers have been combined with chemical and immunosensors. Fiber imaging probes based on interferometry and computational imaging are also discussed as emerging in vivo diagnostic devices. We provide examples to illustrate how the convergence of multiple scientific disciplines generates opportunities for the fiber probes to address key challenges in real-time in vivo diagnostics. These future fiber probes will enable the asking and answering of scientific questions that were never possible before.Jiawen Li ... Heike Ebendorff-Heidepriem ... Mark R. Hutchinson ... Roman Kostecki ... Erik P. Schartner ... Georgios Tsiminis ... Stephen C. Warren-Smith ... et al

Strategies towards enabling lithium metal in batteries: interphases and electrodes

Despite the continuous increase in capacity, lithium-ion intercalation batteries are approaching their performance limits. As a result, research is intensifying on next-generation battery technologies. The use of a lithium metal anode promises the highest theoretical energy density and enables use of lithium-free or novel high-energy cathodes. However, the lithium metal anode suffers from poor morphological stability and Coulombic efficiency during cycling, especially in liquid electrolytes. In contrast to solid electrolytes, liquid electrolytes have the advantage of high ionic conductivity and good wetting of the anode, despite the lithium metal volume change during cycling. Rapid capacity fade due to inhomogeneous deposition and dissolution of lithium is the main hindrance to the successful utilization of the lithium metal anode in combination with liquid electrolytes. In this perspective, we discuss how experimental and theoretical insights can provide possible pathways for reversible cycling of twodimensional lithium metal. Therefore, we discuss improvements in the understanding of lithium metal nucleation, deposition, and stripping on the nanoscale. As the solid–electrolyte interphase (SEI) plays a key role in the lithium morphology, we discuss how the proper SEI design might allow stable cycling. We highlight recent advances in conventional and (localized) highly concentrated electrolytes in view of their respective SEIs. We also discuss artificial interphases and three-dimensional host frameworks, which show prospects of mitigating morphological instabilities and suppressing large shape change on the electrode level

Vacationers Happier, but Most not Happier After a Holiday

The aim of this study was to obtain a greater insight into the association between vacations and happiness. We examined whether vacationers differ in happiness, compared to those not going on holiday, and if a holiday trip boosts post-trip happiness. These questions were addressed in a pre-test/post-test design study among 1,530 Dutch individuals. 974 vacationers answered questions about their happiness before and after a holiday trip. Vacationers reported a higher degree of pre-trip happiness, compared to non-vacationers, possibly because they are anticipating their holiday. Only a very relaxed holiday trip boosts vacationers’ happiness further after return. Generally, there is no difference between vacationers’ and non-vacationers’ post-trip happiness. The findings are explained in the light of set-point theory, need theory and comparison theory

Genetic Evidence for a Tight Cooperation of TatB and TatC during Productive Recognition of Twin-Arginine (Tat) Signal Peptides in Escherichia coli

The twin arginine translocation (Tat) pathway transports folded proteins across the cytoplasmic membrane of bacteria. Tat signal peptides contain a consensus motif (S/T-R-R-X-F-L-K) that is thought to play a crucial role in substrate recognition by the Tat translocase. Replacement of the phenylalanine at the +2 consensus position in the signal peptide of a Tat-specific reporter protein (TorA-MalE) by aspartate blocked export of the corresponding TorA(D+2)-MalE precursor, indicating that this mutation prevents a productive binding of the TorA(D+2) signal peptide to the Tat translocase. Mutations were identified in the extreme amino-terminal regions of TatB and TatC that synergistically suppressed the export defect of TorA(D+2)-MalE when present in pairwise or triple combinations. The observed synergistic suppression activities were even more pronounced in the restoration of membrane translocation of another export-defective precursor, TorA(KQ)-MalE, in which the conserved twin arginine residues had been replaced by lysine-glutamine. Collectively, these findings indicate that the extreme amino-terminal regions of TatB and TatC cooperate tightly during recognition and productive binding of Tat-dependent precursor proteins and, furthermore, that TatB and TatC are both involved in the formation of a specific signal peptide binding site that reaches out as far as the end of the TatB transmembrane segment

Visualizing Interactions along the Escherichia coli Twin-Arginine Translocation Pathway Using Protein Fragment Complementation

The twin-arginine translocation (Tat) pathway is well known for its ability to export fully folded substrate proteins out of the cytoplasm of Gram-negative and Gram-positive bacteria. Studies of this mechanism in Escherichia coli have identified numerous transient protein-protein interactions that guide export-competent proteins through the Tat pathway. To visualize these interactions, we have adapted bimolecular fluorescence complementation (BiFC) to detect protein-protein interactions along the Tat pathway of living cells. Fragments of the yellow fluorescent protein (YFP) were fused to soluble and transmembrane factors that participate in the translocation process including Tat substrates, Tat-specific proofreading chaperones and the integral membrane proteins TatABC that form the translocase. Fluorescence analysis of these YFP chimeras revealed a wide range of interactions such as the one between the Tat substrate dimethyl sulfoxide reductase (DmsA) and its dedicated proofreading chaperone DmsD. In addition, BiFC analysis illuminated homo- and hetero-oligomeric complexes of the TatA, TatB and TatC integral membrane proteins that were consistent with the current model of translocase assembly. In the case of TatBC assemblies, we provide the first evidence that these complexes are co-localized at the cell poles. Finally, we used this BiFC approach to capture interactions between the putative Tat receptor complex formed by TatBC and the DmsA substrate or its dedicated chaperone DmsD. Our results demonstrate that BiFC is a powerful approach for studying cytoplasmic and inner membrane interactions underlying bacterial secretory pathways