6,576 research outputs found
Plasma from Volunteers Breathing Helium Reduces Hypoxia-Induced Cell Damage in Human Endothelial Cells-Mechanisms of Remote Protection Against Hypoxia by Helium.
PurposeRemote ischemic preconditioning protects peripheral organs against prolonged ischemia/reperfusion injury via circulating protective factors. Preconditioning with helium protected healthy volunteers against postischemic endothelial dysfunction. We investigated whether plasma from helium-treated volunteers can protect human umbilical vein endothelial cells (HUVECs) against hypoxia in vitro through release of circulating of factors.MethodsHealthy male volunteers inhaled heliox (79% helium, 21% oxygen) or air for 30 min. Plasma was collected at baseline, directly after inhalation, 6 h and 24 h after start of the experiment. HUVECs were incubated with either 5% or 10% of the plasma for 1 or 2 h and subjected to enzymatically induced hypoxia. Cell damage was measured by LDH content. Furthermore, caveolin 1 (Cav-1), hypoxia-inducible factor (HIF1α), extracellular signal-regulated kinase (ERK)1/2, signal transducer and activator of transcription (STAT3) and endothelial nitric oxide synthase (eNOS) were determined.ResultsPrehypoxic exposure to 10% plasma obtained 6 h after helium inhalation decreased hypoxia-induced cell damage in HUVEC. Cav-1 knockdown in HUVEC abolished this effect.ConclusionsPlasma of healthy volunteers breathing helium protects HUVEC against hypoxic cell damage, possibly involving circulating Cav-1
Practice, Entrepreneurship and Subjectivity in Artist Identification with Applications to the Covid-Era
How we define an artist and how we use census and survey data to study artist behaviour is a cornerstone of cultural economics. Frey and Pommerehne (1989) list eight criteria for identifying an artist, from time spent on and income derived from art-making, to reputation and recognition, organizational membership and professional qualifications. We take a radically subjective approach where we use only the last of their categories, artist self-identification, to attempt a theoretical advancement in art economics. Concurrent with the professionalization of economic science at the university and positivism in economic policy emerges a quantitative focus on production in labor markets (Tribe 2022). This seems a Procrustean bed for cultural economics in that artists tend to be self-directed, entrepreneurial and self-employed and when they do work for others, do so only as a second “job” in order to support creative practice (Throsby 1994). This is not a labor market model where income is maximized and redistribution is needed for fairness. There is an over-supply of art, subsidy may not be necessary as may create moral hazard (Benhamou 2003). We use Max Weber (1919)’s original notion of avocation (substantive value) versus vocation (instrumental value) and determine that it may be wrong to fit art-making into the categories of mainstream industrial and labor economics. For our book Artists and Markets in Music (Routledge 2023) we are currently conducting two complementary surveys to understand how musicians have altered their social practice and craft during the covid-era. One survey is of Grammy-members where the criterion for being an artist is to make one’s living at music and follows-on a 2018 survey (Krueger 2019). The second is a grassroots snowball survey where the criterion is self-identification as a musician. The two different surveys might help us to test differing relevancies for the SAD production function in music as proposed by Samuel Cameron (2015, 2016) as well as further identifying market heterogeneity as discussed in Throsby 199
Iridium wire grid polarizer fabricated using atomic layer deposition
In this work, an effective multistep process toward fabrication of an iridium wire grid polarizer for UV applications involving a frequency doubling process based on ultrafast electron beam lithography and atomic layer deposition is presented. The choice of iridium as grating material is based on its good optical properties and a superior oxidation resistance. Furthermore, atomic layer deposition of iridium allows a precise adjustment of the structural parameters of the grating much better than other deposition techniques like sputtering for example. At the target wavelength of 250 nm, a transmission of about 45% and an extinction ratio of 87 are achieved
Intrinsic strong light-matter coupling with self-hybridized bound states in the continuum in van der Waals metasurfaces.
Photonic bound states in the continuum (BICs) provide a standout platform for strong light-matter coupling with transition metal dichalcogenides (TMDCs) but have so far mostly been implemented as traditional all-dielectric metasurfaces with adjacent TMDC layers, incurring limitations related to strain, mode overlap and material integration. Here, we demonstrate intrinsic strong coupling in BIC-driven metasurfaces composed of nanostructured bulk tungsten disulfide (WS2) and exhibiting resonances with sharp, tailored linewidths and selective enhancement of light-matter interactions. Tuning of the BIC resonances across the exciton resonance in bulk WS2 is achieved by varying the metasurface unit cells, enabling strong coupling with an anticrossing pattern and a Rabi splitting of 116 meV. Crucially, the coupling strength itself can be controlled and is shown to be independent of material-intrinsic losses. Our self-hybridized metasurface platform can readily incorporate other TMDCs or excitonic materials to deliver fundamental insights and practical device concepts for polaritonic applications
Granular cell tumour of the soft tissues: a case report and literature review
Granular cell tumours (GCT) of the soft tissues are rare benign tumours but some time may be difficult to distinguish from malignant neoplasms. It is important that clinicians are aware of their existence. We present a new case of GCT of the soft tissues followed by a brief review of literature
Consistent model of magnetism in ferropnictides
The discovery of superconductivity in LaFeAsO introduced the ferropnictides
as a major new class of superconducting compounds with critical temperatures
second only to cuprates. The presence of magnetic iron makes ferropnictides
radically different from cuprates. Antiferromagnetism of the parent compounds
strongly suggests that superconductivity and magnetism are closely related.
However, the character of magnetic interactions and spin fluctuations in
ferropnictides, in spite of vigorous efforts, has until now resisted
understanding within any conventional model of magnetism. Here we show that the
most puzzling features can be naturally reconciled within a rather simple
effective spin model with biquadratic interactions, which is consistent with
electronic structure calculations. By going beyond the Heisenberg model, this
description explains numerous experimentally observed properties, including the
peculiarities of the spin wave spectrum, thin domain walls, crossover from
first to second order phase transition under doping in some compounds, and
offers new insight in the occurrence of the nematic phase above the
antiferromagnetic phase transition.Comment: 5 pages, 3 figures, revtex
Spatial Variation in Pelagic Wildlife Assemblages in the Ascension Island Marine Protected Area: Implications for Monitoring and Management
Bathymetric features such as islands and seamounts, as well as dynamic ocean features such as fronts often harbour rich marine communities. We deployed mid-water baited remote underwater video systems on three expeditions in Ascension Island’s Exclusive Economic Zone (EEZ), surveying the waters associated with six different bathymetric and dynamic ocean features: Ascension Island, two shallow seamounts (summits ≤ 101 m), one deeper seamount (summit > 250 m), apparent fronts, and haphazardly sampled open ocean areas. At Ascension Island, the pelagic assemblage consisted of a moderate proportion of predators and a diverse range of other taxa, including turtles, dolphins, and large non-piscivores. At the two shallow seamounts, sharks, tunas, billfish, and other large pelagic predators formed the vast majority of the assemblage, contributing > 99.9% of biomass and > 86% of abundance. At the deeper seamount, the pelagic community was comparatively depauperate, however the functional composition of its assemblage indicated some similarities to the shallow seamounts. Apparent fronts did not significantly differ from random offshore sites for metrics such as total abundance and taxonomic richness. However, they harboured assemblages with more abundant sharks, tunas, and large piscivores than random ocean open locations and these differences may be driven by certain front-associated species. Our results illustrate that pelagic assemblages vary markedly among different physical and oceanographic features and that seamounts appear particularly important for pelagic predators. The diversity and abundance of the assemblage, as well as the threatened status of many of the species observed, serve to highlight the conservation value of the Ascension Island EEZ. Our results also provide important baseline information of pelagic wildlife assemblages against which the performance of the recently implemented Ascension Island Marine Protected Area can be evaluated
- …