Quantitative assessment of desirability of platform cell culture media

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What’s Wrong with Digital Stewardship: Evaluating the Organization of Digital Preservation Programs from Practitioners’ Perspectives

The National Digital Stewardship Alliance surveyed practitioners in 2012 and again in 2017 to gauge, among other things, how satisfied they were with their organizations’ digital preservation function. This study seeks to understand what causes the high and rising levels of dissatisfaction that practitioners reported. We interviewed 21 digital stewards and asked them to describe the organizational context in which they work; to reflect on what aspects of their organizations’ approach to digital preservation are working well and which are not; and to evaluate necessary areas of improvement. We identified experiences that were common among participants using a qualitative research methodology based on phenomenology. These conversations revealed that practitioners largely consider digital stewardship values and goals to be misunderstood at an organizational level, and demonstrated that the absence of a long-term vision for digital stewardship disempowers practitioners

An Expert Instructor’s Use of Social Congruence, Cognitive Congruence, and Expertise in an Online Case-Based Instructional Design Course

Promoting and sustaining effective discussion—that which contributes to learning—is a skill that eludes many instructors (Darling-Hammond, 2008; Ge, Yamashiro, & Lee, 2000). This study explored the role and strategies of an expert instructor in an online advanced instructional design (ID) course that utilized a case-based learning (CBL) approach. Discussion posts, as well as interview data, were analyzed and coded to explore how the instructor utilized three strategies noted as being critical to students’ learning during problem-centered discussions: social congruence, cognitive congruence, and content expertise (Schmidt & Moust, 1995; Yew & Yong, 2014). Results showed that facilitation choices were made with course goals in mind: modeling the case analysis process and improving students’ ID problem solving. All three strategies were used frequently during discussion facilitation. Strategies tended to be implemented in clusters, with social congruence strategies appearing in every post but four. Implications are discussed for utilizing a combination of these facilitation strategies, in a dynamic manner, within a case-based context

Flight Test Overview for UAS Integration in the NAS Project

The National Aeronautics and Space Administration is conducting a series of flight tests intended to support the reduction of barriers that prevent unmanned aircraft from flying without the required waivers from the Federal Aviation Administration. The most recent testing supported two separate test configurations. The first investigated the timing of Detect and Avoid (DAA) alerting thresholds using a radar-equipped unmanned vehicle and multiple live intruders flown at varying encounter geometries. The second configuration included a surrogate unmanned vehicle (flown from a ground control station, with a safety pilot on board) flying a mission in a virtual air traffic control airspace sector using research pilot displays and DAA advisories to maintain separation from live and virtual aircraft. The test was conducted over a seven-week span in the summer of 2015. The data from over 100 encounter sorties will be used to inform the RTCA Phase 1 Detect and Avoid and Command and Control Minimum Operating Performance Standards (MOPS) intended to be completed by the summer of 2016. Follow-on flight-testing is planned for the spring of 2016 to capture remaining encounters and support validation of the MOPS

Heterogeneity in HIV and cellular transcription profiles in cell line models of latent and productive infection: implications for HIV latency.

BackgroundHIV-infected cell lines are widely used to study latent HIV infection, which is considered the main barrier to HIV cure. We hypothesized that these cell lines differ from each other and from cells from HIV-infected individuals in the mechanisms underlying latency.ResultsTo quantify the degree to which HIV expression is inhibited by blocks at different stages of HIV transcription, we employed a recently-described panel of RT-ddPCR assays to measure levels of 7 HIV transcripts ("read-through," initiated, 5' elongated, mid-transcribed/unspliced [Pol], distal-transcribed [Nef], polyadenylated, and multiply-sliced [Tat-Rev]) in bulk populations of latently-infected (U1, ACH-2, J-Lat) and productively-infected (8E5, activated J-Lat) cell lines. To assess single-cell variation and investigate cellular genes associated with HIV transcriptional blocks, we developed a novel multiplex qPCR panel and quantified single cell levels of 7 HIV targets and 89 cellular transcripts in latently- and productively-infected cell lines. The bulk cell HIV transcription profile differed dramatically between cell lines and cells from ART-suppressed individuals. Compared to cells from ART-suppressed individuals, latent cell lines showed lower levels of HIV transcriptional initiation and higher levels of polyadenylation and splicing. ACH-2 and J-Lat cells showed different forms of transcriptional interference, while U1 cells showed a block to elongation. Single-cell studies revealed marked variation between/within cell lines in expression of HIV transcripts, T cell phenotypic markers, antiviral factors, and genes implicated in latency. Expression of multiply-spliced HIV Tat-Rev was associated with expression of cellular genes involved in activation, tissue retention, T cell transcription, and apoptosis/survival.ConclusionsHIV-infected cell lines differ from each other and from cells from ART-treated individuals in the mechanisms governing latent HIV infection. These differences in viral and cellular gene expression must be considered when gauging the suitability of a given cell line for future research on HIV. At the same time, some features were shared across cell lines, such as low expression of antiviral defense genes and a relationship between productive infection and genes involved in survival. These features may contribute to HIV latency or persistence in vivo, and deserve further study using novel single cell assays such as those described in this manuscript

Mechanisms and efficacy of small molecule latency-promoting agents to inhibit HIV reactivation ex vivo.

Drugs that inhibit HIV transcription and/or reactivation of latent HIV have been proposed as a strategy to reduce HIV-associated immune activation or to achieve a functional cure, yet comparative studies are lacking. We evaluated 26 drugs, including drugs previously reported to inhibit HIV transcription (inhibitors of Tat-dependent HIV transcription, Rev, HSF-1/PTEF-b, HSP90, Jak/Stat, or SIRT1/Tat deacetylation) and other agents that were not tested before (inhibitors of PKC, NF-κB, SP-1, or histone acetyltransferase; NR2F1 agonists), elongation (inhibitors of CDK9/ PTEF-b), completion (inhibitors of PolyA-polymerase), or splicing (inhibitors of human splice factors). To investigate if those drugs would vary in their ability to affect different blocks to HIV transcription, we measured levels of initiated, elongated, midtranscribed, completed, and multiply spliced HIV RNA in PBMCs from antiretroviral therapy-suppressed individuals following ex vivo treatment with each drug and subsequent T cell activation. We identified new drugs that prevent HIV reactivation, including CDK and splicing inhibitors. While some drugs inhibited 1 or 2 steps, other drugs (CDK inhibitors, splicing inhibitors, tanespimycin, and triptolide) inhibited multiple stages of HIV transcription and blocked the production of supernatant viral RNA. These drugs and targets deserve further study in strategies aimed at reducing HIV-associated immune activation or achieving a functional cure

Differential susceptibility of cells infected with defective and intact HIV proviruses to killing by obatoclax and other small molecules

ObjectivesSome drugs that augment cell-intrinsic defenses or modulate cell death/survival pathways have been reported to selectively kill cells infected with HIV or Simian Immunodeficiency Virus (SIV), but comparative studies are lacking. We hypothesized that these drugs may differ in their ability to kill cells infected with intact and defective proviruses.DesignTo investigate this hypothesis, drugs were tested ex vivo on peripheral blood mononuclear cells (PBMC) from nine antiretroviral therapy (ART)-suppressed individuals.MethodsWe tested drugs currently in clinical use or human trials, including auranofin (p53 modulator), interferon alpha2A, interferon gamma, acitretin (RIG-I inducer), GS-9620/vesatolimod (TLR7 agonist), nivolumab (PD-1 blocker), obatoclax (Bcl-2 inhibitor), birinapant [inhibitor of apoptosis proteins (IAP) inhibitor], bortezomib (proteasome inhibitor), and INK128/sapanisertib [mammalian target of rapamycin mTOR] [c]1/2 inhibitor). After 6 days of treatment, we measured cell counts/viabilities and quantified levels of total, intact, and defective HIV DNA by droplet digital PCR (Intact Proviral DNA Assay).ResultsObatoclax reduced intact HIV DNA [median = 27-30% of dimethyl sulfoxide control (DMSO)] but not defective or total HIV DNA. Other drugs showed no statistically significant effects.ConclusionObatoclax and other Bcl-2 inhibitors deserve further study in combination therapies aimed at reducing the intact HIV reservoir in order to achieve a functional cure and/or reduce HIV-associated immune activation

Changing expectations about speed alters perceived motion direction

SummaryOur perceptions are fundamentally altered by our knowledge of the world. When cloud-gazing, for example, we tend spontaneously to recognize known objects in the random configurations of evaporated moisture. How our brains acquire such knowledge and how it impacts our perceptions is a matter of heated discussion. A topic of recent debate has concerned the hypothesis that our visual system ‘assumes’ that objects are static or move slowly [1] rather than more quickly [1–3]. This hypothesis, or ‘prior on slow speeds’, was postulated because it could elegantly explain a number of perceptual biases observed in situations of uncertainty [2]. Interestingly, those biases affect not only the perception of speed, but also the direction of motion. For example, the direction of a line whose endpoints are hidden (as in the ‘aperture problem’) or poorly visible (for example, at low contrast or for short presentations) is more often perceived as being perpendicular to the line than it really is — an illusion consistent with expecting that the line moves more slowly than it really does. How this ‘prior on slow speeds’ is shaped by experience and whether it remains malleable in adults is unclear. Here, we show that systematic exposure to high-speed stimuli can lead to a reversal of this direction illusion. This suggests that the shaping of the brain's prior expectations of even the most basic properties of the environment is a continuous process