Accurate modelling for the analysis and design of liquid-crystal-based microwave devices

Liquid crystal substrates have been shown to provide the means to develop low-cost, reconfigurable, adaptive and tuneable microwave and MM-wave devices for mobile and wireless communication systems. However, techniques for the characterisation of materials, device fabrication and design are necessary in order to take maximum advantage of the possibilities that these materials offer. This includes appropriate modelling methods to simulate accurately the switching behaviour of the liquid crystal and the characteristics of the wave propagation through the devices, taking full consideration of the point-by-point variation of the material tensor permittivity. We describe these techniques here and show their application in the design of a meander-line phase shifter

Amino Acids Generated from Hydrated Titan Tholins: Comparison with Miller-Urey Electric Discharge Products

Various analogues of Titan haze particles (termed tholins) have been made in the laboratory. In certain geologic environments on Titan, these haze particles may come into contact with aqueous ammonia (NH3) solutions, hydrolyzing them into molecules of astrobiological interest. A Titan tholin analogue hydrolyzed in aqueous NH3 at room temperature for 2.5 years was analyzed for amino acids using highly sensitive ultra-high performance liquid chromatography coupled with fluorescence detection and time-of-flight mass spectrometry (UHPLC-FDToF-MS) analysis after derivatization with a fluorescent tag. We compare here the amino acids produced from this reaction sequence with those generated from room temperature Miller-Urey (MU) type electric discharge reactions. We find that most of the amino acids detected in low temperature MU CH4N2H2O electric discharge reactions are generated in Titan simulation reactions, as well as in previous simulations of Triton chemistry. This argues that many processes provide very similar mixtures of amino acids, and possibly other types of organic compounds, in disparate environments, regardless of the order of hydration. Although it is unknown how life began, it is likely that given reducing conditions, similar materials were available throughout the early Solar System and throughout the universe to facilitate chemical evolution

Ultralow-threshold, continuous-wave upconverting lasing from subwavelength plasmons.

Miniaturized lasers are an emerging platform for generating coherent light for quantum photonics, in vivo cellular imaging, solid-state lighting and fast three-dimensional sensing in smartphones1-3. Continuous-wave lasing at room temperature is critical for integration with opto-electronic devices and optimal modulation of optical interactions4,5. Plasmonic nanocavities integrated with gain can generate coherent light at subwavelength scales6-9, beyond the diffraction limit that constrains mode volumes in dielectric cavities such as semiconducting nanowires10,11. However, insufficient gain with respect to losses and thermal instabilities in nanocavities has limited all nanoscale lasers to pulsed pump sources and/or low-temperature operation6-9,12-15. Here, we show continuous-wave upconverting lasing at room temperature with record-low thresholds and high photostability from subwavelength plasmons. We achieve selective, single-mode lasing from Yb3+/Er3+-co-doped upconverting nanoparticles conformally coated on Ag nanopillar arrays that support a single, sharp lattice plasmon cavity mode and greater than wavelength λ/20 field confinement in the vertical dimension. The intense electromagnetic near-fields localized in the vicinity of the nanopillars result in a threshold of 70 W cm-2, orders of magnitude lower than other small lasers. Our plasmon-nanoarray upconverting lasers provide directional, ultra-stable output at visible frequencies under near-infrared pumping, even after six hours of constant operation, which offers prospects in previously unrealizable applications of coherent nanoscale light

G-Structures, Fluxes and Calibrations in M-Theory

We study the most general supersymmetric warped M-theory backgrounds with non-trivial G-flux of the type R^{1,2} x M_8 and AdS_3 x M_8. We give a set of necessary and sufficient conditions for preservation of supersymmetry which are phrased in terms of G-structures and their intrinsic torsion. These equations may be interpreted as calibration conditions for a static ``dyonic'' M-brane, that is, an M5-brane with self-dual three-form turned on. When the electric flux is turned off we obtain the supersymmetry conditions and non-linear PDEs describing M5-branes wrapped on associative and special Lagrangian three-cycles in manifolds with G_2 and SU(3) structures, respectively. As an illustration of our formalism, we recover the 1/2-BPS dyonic M-brane, and also construct some new examples.Comment: 40 pages; v2: one reference added, typos correcte

Comparison of the reverse bevel versus Franseen type endoscopic ultrasound needle

BACKGROUNDReverse bevel (RB) needle is widely used for endoscopic ultrasound fine needle biopsy (EUS-FNB). A 3-plane symmetrical needle with Franseen geometry (FG) has recently become available. AIMTo compare the clinical efficacy of FG to that of RB needle.METHODSA retrospective cohort study of all adult patients who underwent EUS-FNB for solid and mixed lesions either with 22G RB needle or 22G FG needle between January 2016 and February 2019 was undertaken. All cytology slides were reviewed by an independent gastrointestinal cytopathologist blinded to the needle used and the initial cytology report. The primary and secondary outcomes were to assess the sample adequacy using Euro-cytology criteria and the number of cell clusters, respectively.RESULTSTwo hundred and twenty six procedures were included in the study. RB needle was used in 128 procedures and FG needle in 98 procedures. The baseline characteristics of both groups were comparable. On multivariable analysis, FG needle (P = 0.02) and location of the lesion (P < 0.01) were independently associated with adequate tissue. Further, the use of FG needle (P = 0.04) and the size of the lesion (P = 0.02) were independently associated with acquisition of increased number of cell clusters.CONCLUSIONFG needle is superior to RB needle in acquiring adequate tissue and attaining higher number of cell clusters for solid and mixed lesions

Conducting Miller-Urey Experiments

In 1953, Stanley Miller reported the production of biomolecules from simple gaseous starting materials, using apparatus constructed to simulate the primordial Earth's atmosphere-ocean system. Miller introduced 200 ml of water, 100 mmHg of H2, 200mmHg of CH4, and 200mmHg of NH3 into the apparatus, then subjected this mixture, under reflux, to an electric discharge for a week, while the water was simultaneously heated. The purpose of this manuscript is to provide the reader with a general experimental protocol that can be used to conduct a Miller-Urey type spark discharge experiment, using a simplified 3 L reaction flask. Since the experiment involves exposing inflammable gases to a high voltage discharge, it is worth highlighting important steps that reduce the risk of explosion. The general procedures described in this work can be extrapolated to design and conduct a wide variety of electric discharge experiments simulating primitive planetary environments

Treatment of Psoriasis in Patients With Psoriatic Arthritis: An Updated Literature Review Informing the 2021 GRAPPA Treatment Recommendations

Objective. Our aim was to summarize and evaluate the current quality of evidence regarding the efficacy of therapies for cutaneous psoriasis (PsO) in patients with psoriatic arthritis (PsA).Methods. A literature search of MEDLINE, Embase, Cochrane Library databases, and conference abstracts was conducted to identify interventional randomized controlled trials in patients with PsA between February 2013 and December 2021. Studies were included if PsO outcomes included achieving at least 75% improvement in the Psoriasis Area and Severity Index and the blinded comparison period was &gt;= 10 weeks. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology was employed to assess quality of the evidence to inform and update the 2021 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) treatment recommendations.Results. A total of 116 studies and 36 abstracts identified in the initial search were screened. A total of 37 studies (40 treatment arms) met the criteria for final inclusion. Phosphodiesterase 4 inhibitors, Janus kinase inhibitors, and tyrosine kinase 2 inhibitors, interleukin 17 inhibitors (IL-17i), IL-12/23i, IL-23i, and tumor necrosis factor inhibitors (TNFi) had high-quality data broadly supporting the efficacy of each class for plaque PsO over placebo. Head-to-head studies with high-quality data supported both IL-17i and IL-23i over TNFi.Conclusion. Several pharmacologic therapeutic classes have high-quality evidence demonstrating efficacy for cutaneous PsO in the PsA population. The findings will be integrated into the 2021 GRAPPA treatment recommendations, intended to guide selection of a therapeutic class where efficacy in 1 or more cutaneous or musculoskeletal domains is required

The impact of secondary forest regeneration on ground-dwelling ant communities in the Tropical Andes

Natural regeneration of abandoned farmland provides an important opportunity to contribute to global reforestation targets, including the Bonn Challenge. Of particular importance are the montane tropics, where a long history of farming, frequently on marginal soils, has rendered many ecosystems highly degraded and hotspots of extinction risk. Ants play crucial roles in ecosystem functioning, and a key question is how time since abandonment and elevation (and inherent temperature gradients therein) affect patterns of ant recovery within secondary forest systems. Focusing on the Colombian Andes across a 1300 m altitudinal gradient and secondary forest (2–30 years) recovering on abandoned cattle pastures, we find that over time ant community composition and species richness recovered towards that of primary forest. However, these relationships are strongly dependent on elevation with the more open and warmer pasturelands supporting more ants than either primary or secondary forest at a particular elevation. The loss of species richness and change in species composition with elevation is less severe in pasture than forests, suggesting that conditions within pasture and its remaining scattered trees, hedgerows and forest fragments, are more favourable for some species, which are likely in or near thermal debt. Promoting and protecting natural regenerating forests over the long term in the montane tropics will likely offer significant potential for returning ant communities towards primary forest levels

Structural basis for the RING catalyzed synthesis of K63 linked ubiquitin chains

This work was supported by grants from Cancer Research UK (C434/A13067), the Wellcome Trust (098391/Z/12/Z) and Biotechnology and Biological Sciences Research Council (BB/J016004/1).The RING E3 ligase catalysed formation of lysine 63 linked ubiquitin chains by the Ube2V2–Ubc13 E2 complex is required for many important biological processes. Here we report the structure of the RING domain dimer of rat RNF4 in complex with a human Ubc13~Ub conjugate and Ube2V2. The structure has captured Ube2V2 bound to the acceptor (priming) ubiquitin with Lys63 in a position that could lead to attack on the linkage between the donor (second) ubiquitin and Ubc13 that is held in the active “folded back” conformation by the RING domain of RNF4. The interfaces identified in the structure were verified by in vitro ubiquitination assays of site directed mutants. This represents the first view of the synthesis of Lys63 linked ubiquitin chains in which both substrate ubiquitin and ubiquitin-loaded E2 are juxtaposed to allow E3 ligase mediated catalysis.PostprintPeer reviewe