Affordances-in-practice:an ethnographic critique of social media logic and context collapse

Drawing on data gathered during ethnographic fieldwork in Mardin, a medium-sized town in southeast Turkey, this article shows that social media users actively appropriate online platforms and change privacy settings in order to keep different social spheres and social groups apart. Keeping different online social contexts distinct from each other is taken for granted as a way of using social media in Mardin. By contrast, social media scholars have extensively discussed the effects of social media in terms of context collapse. The article highlights how context collapse is the result of patterns of usage within Anglo-American contexts and not the consequence of a platform's architecture or social media logic. It then suggests a theoretical refinement of affordances, and proposes the concept of affordances-in-practice

Using learning environments as a metaphor for educational change

Purpose – The purpose of this paper is to show that the online learning environment can be seen as the means by which higher education can explore the challenges and opportunities raised by online and digital society. Design/methodology/approach – The paper argues that the online learning environment can be seen as a metaphor for how universities respond to the requirements and challenges of the digital age. Current learning management systems (LMSs) are examined, and compared with the values found in web 2.0 and social media. Current thinking on pedagogy for online learning is then examined. The SocialLearn project at the Open University in the UK is then explained, which seeks to create a disaggregated, decentralised, social system for learners. Findings – The conclusion from the analysis is that there is a conflict between the centralised learning management system (LMS) and the requirements of online pedagogy. The traditional LMS can be seen as embodying the wrong metaphor, that of the traditional classroom. The paper concludes by arguing that such learning environments will be more useful to higher education in coming to understand its response to many of the changes being seen in society, which are facilitated by the new technologies. Originality/value – The paper provides a framework for considering LMSs and their relation to universities and pedagogy, and an argument for the promotion of more decentralised systems

Pitfalls in the characterization of circulating and tissue-resident human γδ T cells

Dissection of the role and function of human γδ T cells and their heterogeneous subsets in cancer, inflammation, and auto-immune diseases is a growing and dynamic research field of increasing interest to the scientific community. Therefore, harmonization and standardization of techniques for the characterization of peripheral and tissue-resident γδ T cells is crucial to facilitate comparability between published and emerging research. The application of commercially available reagents to classify γδ T cells, in particular the combination of multiple Abs, is not always trouble-free, posing major demands on researchers entering this field. Occasionally, even entire γδ T cell subsets may remain undetected when certain Abs are combined in flow cytometric analysis with multicolor Ab panels, or might be lost during cell isolation procedures. Here, based on the recent literature and our own experience, we provide an overview of methods commonly employed for the phenotypic and functional characterization of human γδ T cells including advanced polychromatic flow cytometry, mass cytometry, immunohistochemistry, and magnetic cell isolation. We highlight potential pitfalls and discuss how to circumvent these obstacles

Recreational drugs and sexual behavior in the Chicago MACS/CCS cohort of homosexually active men

Since initial reports emerged of an association between recreational drug use and high-risk sexual behaviors in gay men, there has been interest in studying this relationship for its relevance to behavioral interventions. Reported here are the longitudinal patterns of alcohol and recreational drug use in the Chicago Multicenter AIDS Cohort Study (MACS)/Coping and Change Study (CCS) of gay men. A pattern of decreasing drug use over 6 years was observed that paralleled a decline in high-risk sexual behavior (i.e., unprotected anal intercourse). In contrast, alcohol consumption tended to be more stable over time, and to show no relationship to sexual behavior change. Men who combined volatile nitrite (popper) use with other recreational drugs were at highest risk both behaviorally and in terms of human immunodeficiency virus-1 (HIV) seroconversion throughout the study. Popper use also was associated independently with lapse from safer sexual behaviors (failure to use a condom during receptive anal sex). Use of other recreational substances showed no relationship to sexual behavior change patterns, and stopping popper use was unrelated to improvement in safer sexual behavior. When popper use and lapse from safer sex were reanalyzed, controlling for primary relationship status, popper use was associated with failure to use condoms during receptive anal sex among nonmonogamous men only. These findings suggest an association between popper use and high-risk sexual behavior among members of the Chicago MACS/CCS cohort that has relevance to HIV prevention intervention efforts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31072/1/0000749.pd

Observation of soft X-ray Cherenkov radiation in Al

The soft X-ray radiation generated by 5.7 MeV electrons from both an Al foil and a Mylar film in forward direction was experimentally studied. A narrow specific directivity, an ultra-narrow spectral bandwidth and a good consistency between the experiment and theory prove that the Cherenkov radiation (CR) with photon energy near the L-edge of absorption in Al was observed. The results demonstrate that the CR spectral-angular properties and the absolute photon yield can be described well enough using Pafomov's theoretical model and Henke's refractive index database, which is essential for all practical applications

Assessing the Completeness of Reporting in Preclinical Oncolytic Virus Therapy Studies

Irreproducibility of preclinical findings could be a significant barrier to the “bench-to-bedside” development of oncolytic viruses (OVs). A contributing factor is the incomplete and non-transparent reporting of study methodology and design. Using the NIH Principles and Guidelines for Reporting Preclinical Research, a core set of seven recommendations, we evaluated the completeness of reporting of preclinical OV studies. We also developed an evidence map identifying the current trends in OV research. A systematic search of MEDLINE and Embase identified all relevant articles published over an 18 month period. We screened 1,554 articles, and 236 met our a priori-defined inclusion criteria. Adenovirus (43%) was the most commonly used viral platform. Frequently investigated cancers included colorectal (14%), skin (12%), and breast (11%). Xenograft implantation (61%) in mice (96%) was the most common animal model. The use of preclinical reporting guidelines was listed in 0.4% of articles. Biological and technical replicates were completely reported in 1% of studies, statistics in 49%, randomization in 1%, blinding in 2%, sample size estimation in 0%, and inclusion/exclusion criteria in 0%. Overall, completeness of reporting in the preclinical OV therapy literature is poor. This may hinder efforts to interpret, replicate, and ultimately translate promising preclinical OV findings

Helicobacter pylori Induces Activation of Human Peripheral γδ+ T Lymphocytes

Helicobacter pylori is a Gram-negative bacterium that causes gastric and duodenal diseases in humans. Despite a robust antibody and cellular immune response, H. pylori infection persists chronically. To understand if and how H. pylori could modulate T cell activation, in the present study we investigated in vitro the interaction between H. pylori and human T lymphocytes freshly isolated from peripheral blood of H. pylori-negative donors. A direct interaction of live, but not killed bacteria with purified CD3+ T lymphocytes was observed by microscopy and confirmed by flow cytometry. Live H. pylori activated CD3+ T lymphocytes and predominantly γδ+ T cells bearing the TCR chain Vδ2. Upon interaction with H. pylori, these cells up-regulated the activation molecule CD69 and produced cytokines (such as TNFα, IFNγ) and chemokines (such as MIP-1β, RANTES) in a non-antigen-specific manner. This activation required viable H. pylori and was not exhibited by other Gram-negative bacteria. The cytotoxin-associated antigen-A (CagA), was at least partially responsible of this activation. Our results suggest that H. pylori can directly interact with T cells and modulate the response of γδ+ T cells, thereby favouring an inflammatory environment which can contribute to the chronic persistence of the bacteria and eventually to the gastric pathology

Selective autophagy maintains centrosome integrity and accurate mitosis by turnover of centriolar satellites

The centrosome is the master orchestrator of mitotic spindle formation and chromosome segregation in animal cells. Centrosome abnormalities are frequently observed in cancer, but little is known of their origin and about pathways affecting centrosome homeostasis. Here we show that autophagy preserves centrosome organization and stability through selective turnover of centriolar satellite components, a process we termed doryphagy. Autophagy targets the satellite organizer PCM1 by interacting with GABARAPs via a C-terminal LIR motif. Accordingly, autophagy deficiency results in accumulation of large abnormal centriolar satellites and a resultant dysregulation of centrosome composition. These alterations have critical impact on centrosome stability and lead to mitotic centrosome fragmentation and unbalanced chromosome segregation. Our findings identify doryphagy as an important centrosome-regulating pathway and bring mechanistic insights to the link between autophagy dysfunction and chromosomal instability. In addition, we highlight the vital role of centriolar satellites in maintaining centrosome integrity