248 research outputs found
New Perspectives on Audience Activity: ‘Prosumption’ and Media Activism as Audience Practices
Until relatively recently, the subject of social relationships, constituted in and through audience practices, has been a minor part of audience research studies. This chapter explores how social relationships and forms of audience agency change and / or evolve, through the usage of both traditional and ‘new’ media. In a media environment where traditional and new media worlds collide, the potential of audience practices to rework, not only media-audience relationships, but also wider social relationships, is now an important research theme. Two key examples of mediated relationships between social actors in conditions brought about through transformations in media culture are considered. We look at the evolution of audience ‘prosumption’ or ‘produsage’ (Bruns 2007), as well as at audience ‘activism’ (de Jong, Shaw and Stammers 2005). These examples are identified as illustrating new dynamics of social interaction, which may have the potential to contribute to larger, integrative social networks that transcend the existing boundaries of the traditional concept of audience. Against the background of traditional approaches to social relationships in the context of audience studies, we examine in both case studies the respective roles of the technologies, the social actors and the emergent social relationships concerned
High resolution propagation-based lung imaging at clinically relevant X-ray dose levels
Absorption-based clinical computed tomography (CT) is the current imaging method of choice in the diagnosis of lung diseases. Many pulmonary diseases are affecting microscopic structures of the lung, such as terminal bronchi, alveolar spaces, sublobular blood vessels or the pulmonary interstitial tissue. As spatial resolution in CT is limited by the clinically acceptable applied X-ray dose, a comprehensive diagnosis of conditions such as interstitial lung disease, idiopathic pulmonary fibrosis or the characterization of small pulmonary nodules is limited and may require additional validation by invasive lung biopsies. Propagation-based imaging (PBI) is a phase sensitive X-ray imaging technique capable of reaching high spatial resolutions at relatively low applied radiation dose levels. In this publication, we present technical refinements of PBI for the characterization of different artificial lung pathologies, mimicking clinically relevant patterns in ventilated fresh porcine lungs in a human-scale chest phantom. The combination of a very large propagation distance of 10.7 m and a photon counting detector with [Formula: see text] pixel size enabled high resolution PBI CT with significantly improved dose efficiency, measured by thermoluminescence detectors. Image quality was directly compared with state-of-the-art clinical CT. PBI with increased propagation distance was found to provide improved image quality at the same or even lower X-ray dose levels than clinical CT. By combining PBI with iodine k-edge subtraction imaging we further demonstrate that, the high quality of the calculated iodine concentration maps might be a potential tool for the analysis of lung perfusion in great detail. Our results indicate PBI to be of great value for accurate diagnosis of lung disease in patients as it allows to depict pathological lesions non-invasively at high resolution in 3D. This will especially benefit patients at high risk of complications from invasive lung biopsies such as in the setting of suspected idiopathic pulmonary fibrosis (IPF)
Sphingomyelinase inhibitory and free radical scavenging potential of selected Nigerian medicinal plant extracts
Ceramides from sphingolipid breakdown, and other sphingolipid
metabolites, mediate cellular signalling in infectious and other
diseases. Therefore, inhibitors of sphingomyelinases (SMases), hold
promise as prospective therapeutic agents. Considering the potential
therapeutic utility, this in vitro study explored the sphingomyelinase
inhibitory, and free radical scavenging potential of five Nigerian
medicinal plant leaf extracts, purported to have efficacy against
diseases, including HIV/AIDS. The extracts\u2019 sphingomyelinase
inhibitory potencies were assessed colorimetrically and theirfree
radical scavenging capabilities were assayed by the ability to quench
2,2\u2010diphenyl\u20101\u2010picrylhydrazyl (DPPH) radical and
superoxide anion (O2.\u2010) radical. Considering their IC50
(\u3bcg/ml) values, the extracts inhibited the biochemical activity of
sphingomyelinase in a dose-dependent manner, relative to imipramine the
standard inhibitor (IC50 38.5 \ub1 2.4 \u3bcg/ml). With Aloe vera as
least inhibitory, inhibition increased as follows: Aloe vera
(Asphodelaceae) (1132 \ub1 10.8) < Senna siamea (Fabaceae)
(992.2 \ub1 11.2) < Azadirachta indica (Meliaceae) (984 \ub1
7.4) < Landolphia owariensis (Apocynaceae) (146.3 \ub1 9.4) <
Stachytarpheta angustifolia (Verbenacae) (100.3 \ub1 8.7). DPPH
radical scavenging relative to ascorbic acid standard increased as: A.
indica < A. vera < S. siamea < S. angustifolia < L.
owariensis; and superoxide anion quenching, relative to standard rutin
increased as: A. vera < S. angustifolia < L. owariensis < S.
siamea < A. indica.These results showed thatthe most potent SMase
inhibitor was S. angustifolia; whereas, for DPPH radical scavenging and
superoxide inhibition, the most potent of the five extracts were L.
owariensis and A. indica respectively.These extracts deserve further
investigation into their biological effects
Differences in osmotolerance in freshwater and brackish water populations of Theodoxus fluviatilis (Gastropoda: Neritidae) are associated with differential protein expression
The euryhaline gastropod Theodoxus fluviatilis is found in northern Germany in freshwater or in brackish water habitats in the Baltic Sea. Previous studies have revealed that individuals from both habitats are not distinguishable by morphological characters or by sequence comparison of DNA encoding 16S RNA or cytochrome C. As reported in this study, animals collected in the two habitats differ substantially in their physiological ability to adapt to different salinities. Comparison of accumulation rates of ninhydrin-positive substances (NPS) in foot muscle upon transfer of animals to higher medium salinities revealed that brackish water animals were perfectly able to mobilize NPS, while freshwater animals had only limited ability to do so. In an attempt to explore whether this difference in physiology may be caused by genetic differentiation, we compared protein expression patterns of soluble foot muscle proteins using 2D gel electrophoresis and silver staining. Of the 40 consistently detected protein spots, 27 showed similar levels in protein expression in animals collected from freshwater or brackish water habitats, respectively. In 12 spots, however, protein concentration was higher in brackish water than in freshwater animals. In four of these spots, expression levels followed increases or decreases in medium salinities. In a different set of 4 of these 12 spots, protein levels were always higher in brackish water as compared to freshwater animals, regardless of their physiological situation (14 days in artificial pond water or in medium with a salinity of 16‰). The remaining 4 of the 12 spots had complex expression patterns. Protein levels of the remaining single spot were generally higher in freshwater animals than in brackish water animals. These expression patterns may indicate that freshwater and brackish water animals of T. fluviatilis belong to different locally adapted populations with subtle genetic differentiation
Broad cross-reactivity across sarbecoviruses exhibited by a subset of COVID-19 donor-derived neutralizing antibodies
Many anti-SARS-CoV-2 neutralizing antibodies target the ACE2-binding site on viral spike receptor-binding domains (RBDs). The most potent antibodies recognize exposed variable epitopes, often rendering them ineffective against other sarbecoviruses and SARS-CoV-2 variants. Class 4 anti-RBD antibodies against a less-exposed, but more-conserved, cryptic epitope could recognize newly-emergent zoonotic sarbecoviruses and variants, but usually show only weak neutralization potencies. We characterized two class 4 anti-RBD antibodies derived from COVID-19 donors that exhibited broad recognition and potent neutralization of zoonotic coronavirus and SARS-CoV-2 variants. C118-RBD and C022-RBD structures revealed CDRH3 mainchain H-bond interactions that extended an RBD β-sheet, thus reducing sensitivity to RBD sidechain changes, and epitopes that extended from the cryptic epitope to occlude ACE2 binding. A C118-spike trimer structure revealed rotated RBDs to allow cryptic epitope access and the potential for intra-spike crosslinking to increase avidity. These studies facilitate vaccine design and illustrate potential advantages of class 4 RBD-binding antibody therapeutics
Neuroprotective Effect of Combination Therapy of Glatiramer Acetate and Epigallocatechin-3-Gallate in Neuroinflammation
Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system. However, studies of MS and the animal model, experimental autoimmune encephalomyelitis (EAE), indicate that neuronal pathology is the principle cause of clinical disability. Thus, there is need to develop new therapeutic strategies that not only address immunomodulation but also neuroprotection. Here we show that the combination therapy of Glatiramer acetate (GA), an immunomodulatory MS therapeutic, and the neuroprotectant epigallocatechin-3-gallate (EGCG), the main phenol in green tea, have synergistic protective effects in vitro and in the EAE model. EGCG and GA together led to increased protection from glutamate- and TRAIL-induced neuronal cell death in vitro. EGCG combined with GA induced regeneration of hippocampal axons in an outgrowth assay. The combined application of EGCG and GA did not result in unexpected adverse events in vivo. Neuroprotective and neuroregenerative effects could be translated in the in vivo model, where combination treatment with EGCG and GA significantly delayed disease onset, strongly reduced clinical severity, even after onset of symptoms and reduced inflammatory infiltrates. These results illustrate the promise of combining neuroprotective and anti-inflammatory treatments and strengthen the prospects of EGCG as an adjunct therapy for neuroinflammatory and neurodegenerative diseases
Antibody to Aquaporin 4 in the Diagnosis of Neuromyelitis Optica
BACKGROUND: Neuromyelitis optica (NMO) is a demyelinating disease of the central nervous system (CNS) of putative autoimmune aetiology. Early discrimination between multiple sclerosis (MS) and NMO is important, as optimum treatment for both diseases may differ considerably. Recently, using indirect immunofluorescence analysis, a new serum autoantibody (NMO-IgG) has been detected in NMO patients. The binding sites of this autoantibody were reported to colocalize with aquaporin 4 (AQP4) water channels. Thus we hypothesized that AQP4 antibodies in fact characterize NMO patients. METHODS AND FINDINGS: Based on these observations we cloned human water channel AQP4, expressed the protein in a eukaryotic transcription/translation system, and employed the recombinant AQP4 to establish a new radioimmunoprecipitation assay (RIPA). Indeed, application of this RIPA showed that antibodies against AQP4 exist in the majority of patients with NMO (n = 37; 21 positive) as well as in patients with isolated longitudinally extensive transverse myelitis (n = 6; six positive), corresponding to a sensitivity of 62.8% and a specificity of 98.3%. By contrast, AQP4 antibodies were virtually absent in 291 other participants, which included patients with MS (n = 144; four positive), patients with other inflammatory and noninflammatory neurological diseases (n = 73; one positive), patients with systemic autoimmune diseases (n = 45; 0 positive), and healthy participants (n = 29; 0 positive). CONCLUSIONS: In the largest series reported so far to our knowledge, we quantified AQP4 antibodies in patients with NMO versus various other diseases, and showed that the aquaporin 4 water channel is a target antigen in a majority of patients with NMO. The newly developed assay represents a highly specific, observer-independent, and easily reproducible detection method facilitating clinically relevant discrimination between NMO, MS, and other inflammatory diseases
Mutational escape from the polyclonal antibody response to SARS-CoV-2 infection is largely shaped by a single class of antibodies
Monoclonal antibodies targeting a variety of epitopes have been isolated from individuals previously infected with SARS-CoV-2, but the relative contributions of these different antibody classes to the polyclonal response remains unclear. Here we use a yeast-display system to map all mutations to the viral spike receptor-binding domain (RBD) that escape binding by representatives of three potently neutralizing classes of anti-RBD antibodies with high-resolution structures. We compare the antibody-escape maps to similar maps for convalescent polyclonal plasma, including plasma from individuals from whom some of the antibodies were isolated. The plasma-escape maps most closely resemble those of a single class of antibodies that target an epitope on the RBD that includes site E484. Therefore, although the human immune system can produce antibodies that target diverse RBD epitopes, in practice the polyclonal response to infection is dominated by a single class of antibodies targeting an epitope that is already undergoing rapid evolution
Ecosystems as Commodity Frontiers - Challenges Faced by Land Set Aside as Protected Areas (PAs) in the Dubai Emirate, United Arab Emirates (UAE)
This chapter examines natural habitats in Dubai, UAE that the state has demarcated as protected areas (PAs) in an attempt to utilize them for recreational/economic purposes while also mitigating habitat fragmentation. The authors employ the concept of the ‘commodity frontier’ to demonstrate how these PAs have contributed to the ongoing commodification of land that began with the rise of modern agriculture in the mid-twentieth century. The rise of the oil economy in the mid-twentieth century stimulated significant development that, over time, has resulted in ecological degradation. In line with state conservation agendas aimed at greening the desert and preserving biodiversity, PAs also serve as a mechanism for promoting tourism. Ironically, these activities have in turn put further pressure on the country’s natural resources and desert ecology. The authors also present an example of a PA that has been effectively managed and could serve as a model of sustainable development
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