Continuous thermal melting of a two-dimensional Abrikosov vortex solid

We examine the question of thermal melting of the triangular Abrikosov vortex solid in two-dimensional superconductors or neutral superfluids. We introduce a model, which combines lowest Landau level (LLL) projection with the magnetic Wannier basis to represent degenerate eigenstates in the LLL. Solving the model numerically via large-scale Monte Carlo simulations, we find clear evidence for a continuous melting transition, in perfect agreement with the Kosterlitz-Thouless-Halperin-Nelson-Young theory and with recent experiments.Comment: 4 pages, 2 figures; published versio

Characterization of molecular targets for differential regulation of the type I and III interferon induction and signalling pathways by rotavirus NSP1

Rotavirus (RV) is the leading cause of severe dehydrating diarrhoea in infants, infecting almost every child by 3-5 years of age and causing approximately 590,000 gastroenteritis-associated deaths world-wide both in developed and developing countries. The virus infects the young of all mammalian species and cross-species infections and zoonosis events have been reported. However, RV is host replication-restricted during heterologous infection for reasons that are not fully understood. Type I and type III interferons (IFNs) constitute the first line of defence against viral infection. Their expression is triggered when specific viral components (Pathogen-Associated Molecular Patterns – PAMPs), such as dsRNA, are detected within the cells by specific host proteins, Pattern Recognition Receptors (PRR). Once secreted, IFNs bind their specific receptors inducing the expression of interferon stimulated genes (ISGs), establishing an antiviral state. RV non-structural protein 1 (NSP1), exhibits the greatest sequence variability of any of RV protein. Although non-essential for RV replication in cell culture, NSP1 has been suggested as a virulence factor modulating the host innate immunity. RV NSP1-mediated ability to modulate the IFN response is conserved between strains infecting different species, however, it has been reported that targets within the induction and signalling pathways vary between strains. NSP1 derived from viruses infecting monkeys (RRV, SA) and mice (EW) appear to preferentially target IRF-3 to induce its proteasome-mediated degradation, while NSP1 of porcine origin (OSU) targets β-TrCP, preventing NF-κB activation. In contrast, NSP1 from RV strain UKtc infecting cattle appears to target both IRF-3 and β-TrCP. In order to establish if the observed RV host-range restriction is related to the ability of NSP1 to selectively target different components of the IFN pathways, Y-2-H analysis were performed. A panel of NSP1 derived from RV infecting different mammal species were tested for their binding ability against components of the IFN induction pathway. Indeed NSP1 showed a strain-dependent ability to interact with IRF-3. A series of luciferase reporters have shown that NSP1 was able to downregulate the induction of type I and type III IFNs at their transcriptional level and how this downregulation varied between NSP1 derived from different strains. In addition, NSP1 appeared to target the IFN signalling pathway, blocking ISGs transcription. Moreover, NSP1 showed a strain-dependent expression level

Propiedades tecnológicas de la madera de Citharexylum montevidense (Spreng.) Mol. “Espina de bañado”

Citharexylum montevidense (Spreng.) Mol “Espina de bañado” es una especie nativa empleada artesanalmente en carpintería, construcciones, postes y marcos para aberturas. Sin embargo, no existen estudios tecnológicos que caractericen sus cualidades maderables, los cuales podrían permitir revalorizar su madera hacia productos de mayor valor agregado. El objetivo del presente trabajo fue determinar las propiedades físicas y mecánicas de su madera con el propósito de identificar potenciales nuevos usos. Se determinaron: contenido de humedad, densidad normal, cambios dimensionales, dureza Janka y flexión estática. La densidad (0,68 g.$latex cm^{-3}$ +/- 1208,08). De acuerdo con los valores de dureza Janka hallados, puede considerarse a la madera de Espina de bañando como semidura. Los valores obtenidos en los parámetros físico mecánicos estudiados presumen un buen comportamiento de esta madera al secado, haciéndola apta para la fabricación de pisos, aberturas y muebles.Citharexylum montevidense (Spreng.)Mol a.k.a. “Marsh Thorn” is a native species used in craft carpentry, constructions, posts and door frames. However, there are no studies that characterize technological timber qualities, which could allow wood to revalue its higher value-added products. The aim of this work was to determine the physical and mechanical features of this wood in order to identify potential new uses. Thus water content, normal density, dimensional changes, Janka hardness and static bending were determined. Density values (0.68 g.$latex cm^{-3}$+/- 1208.08). According to the values found for the Janka hardness, the wood ofCitharexylum montevidense (Spreng.) Mol is a semi-hard one. All the values obtained for both the physical and mechanical parameters of this woodletits good behavior be assumed as to the drying process which makes it suitable for the making of floors, openings, and furniture

Quantum State Tomography of Complex Multimode Fields using Array Detectors

We demonstrate that it is possible to use the balanced homodyning with array detectors to measure the quantum state of correlated two-mode signal field. We show the applicability of the method to fields with complex mode functions, thus generalizing the work of Beck (Phys. Rev. Letts. 84, 5748 (2000)) in several important ways. We further establish that, under suitable conditions, array detector measurements from one of the two outputs is sufficient to determine the quantum state of signals. We show the power of the method by reconstructing a truncated Perelomov state which exhibits complicated structure in the joint probability density for the quadratures.Comment: 14 pages text and 3 figures. To be submitted to PR

Time resolved chirp measurements of gain switched semiconductor laser using a polarization based optical differentiator

We present a novel implementation of the “phase reconstruction using optical ultra fast differentiation” (PROUD) technique and apply it to characterize the time resolved chirp of a gain switched semiconductor laser. The optical temporal differentiator is a fiber based polarization interferometer. The method provides a fast and simple recovery of the instantaneous frequency from two temporal intensity measurements, obtained by changing the spectral response of the interferometer. Pulses with different shapes and durations of hundreds of picoseconds are fully characterized in amplitude and phase. The technique is validated by comparing the measured pulse spectra with the reconstructed spectra obtained from the intensity and the recovered phase

The SARS-CoV-2 spike protein binds and modulates estrogen receptors

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein binds angiotensin-converting enzyme 2 as its primary infection mechanism. Interactions between S and endogenous proteins occur after infection but are not well understood. We profiled binding of S against >9000 human proteins and found an interaction between S and human estrogen receptor alpha (ER alpha). Using bioinformatics, supercomputing, and experimental assays, we identified a highly conserved and functional nuclear receptor coregulator (NRC) LXD-like motif on the S2 sub-unit. In cultured cells, S DNA transfection increased ER alpha cytoplasmic accumulation, and S treatment induced ER-dependent biological effects. Non-invasive imaging in SARS-CoV-2-infected hamsters localized lung pathology with increased ER alpha lung levels. Postmortem lung experiments from infected hamsters and humans confirmed an increase in cytoplasmic ER alpha and its colocalization with S in alveolar macrophages. These findings describe the discovery of a S-ER alpha interaction, imply a role for S as an NRC, and advance knowledge of SARS-CoV-2 biology and coronavirus disease 2019 pathology

An organelle-specific protein landscape identifies novel diseases and molecular mechanisms

Cellular organelles provide opportunities to relate biological mechanisms to disease. Here we use affinity proteomics, genetics and cell biology to interrogate cilia: poorly understood organelles, where defects cause genetic diseases. Two hundred and seventeen tagged human ciliary proteins create a final landscape of 1,319 proteins, 4,905 interactions and 52 complexes. Reverse tagging, repetition of purifications and statistical analyses, produce a high-resolution network that reveals organelle-specific interactions and complexes not apparent in larger studies, and links vesicle transport, the cytoskeleton, signalling and ubiquitination to ciliary signalling and proteostasis. We observe sub-complexes in exocyst and intraflagellar transport complexes, which we validate biochemically, and by probing structurally predicted, disruptive, genetic variants from ciliary disease patients. The landscape suggests other genetic diseases could be ciliary including 3M syndrome. We show that 3M genes are involved in ciliogenesis, and that patient fibroblasts lack cilia. Overall, this organelle-specific targeting strategy shows considerable promise for Systems Medicine