434 research outputs found

    Memory and place on the Liverpool waterfront in the mid-twentieth century

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    This article explores the changing urban form and society of waterfront Liverpool in the last generation of the city's role as a traditional general cargo seaport. Deriving much of its evidence from a collaborative public history project, it demonstrates the continuing vitality of the near waterfront zone into the 1960s, and interprets the subsequent sudden collapse of the district with the closure of the south docks in 1972. Interviewees identified sites of memory that cast light on both the routine working of the district and the nature of its fall into dereliction and abandonment

    Lentiviral Vector Production Titer Is Not Limited in HEK293T by Induced Intracellular Innate Immunity

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    Most gene therapy lentiviral vector (LV) production platforms employ HEK293T cells expressing the oncogenic SV40 large T-antigen (TAg) that is thought to promote plasmid-mediated gene expression. Studies on other viral oncogenes suggest that TAg may also inhibit the intracellular autonomous innate immune system that triggers defensive antiviral responses upon detection of viral components by cytosolic sensors. Here we show that an innate response can be generated after HIV-1-derived LV transfection in HEK293T cells, particularly by the transgene, yet, remarkably, this had no effect on LV titer. Further, overexpression of DNA sensing pathway components led to expression of inflammatory cytokine and interferon (IFN) stimulated genes but did not result in detectable IFN or CXCL10 and had no impact on LV titer. Exogenous IFN-β also did not affect LV production or transduction efficiency in primary T cells. Additionally, manipulation of TAg did not affect innate antiviral responses, but stable expression of TAg boosted vector production in HEK293 cells. Our findings demonstrate a measure of innate immune competence in HEK293T cells but, crucially, show that activation of inflammatory signaling is uncoupled from cytokine secretion in these cells. This provides new mechanistic insight into the unique suitability of HEK293T cells for LV manufacture

    A scale down process for the development of large volume cryopreservation.

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    The process of ice formation and propagation during cryopreservation impacts on the post-thaw outcome for a sample. Two processes, either network solidification or progressive solidification, can dominate the water-ice phase transition with network solidification typically present in small sample cryo-straws or cryo-vials. Progressive solidification is more often observed in larger volumes or environmental freezing. These different ice phase progressions could have a significant impact on cryopreservation in scale-up and larger volume cryo-banking protocols necessitating their study when considering cell therapy applications. This study determines the impact of these different processes on alginate encapsulated liver spheroids (ELS) as a model system during cryopreservation, and develops a method to replicate these differences in an economical manner. It was found in the current studies that progressive solidification resulted in fewer, but proportionally more viable cells 24 hr post-thaw compared with network solidification. The differences between the groups diminished at later time points post-thaw as cells recovered the ability to undertake cell division, with no statistically significant differences seen by either 48 hr or 72 hr in recovery cultures. Thus progressive solidification itself should not prove a significant hurdle in the search for successful cryopreservation in large volumes. However, some small but significant differences were noted in total viable cell recoveries and functional assessments between samples cooled with either progressive or network solidification, and these require further investigation

    Cost-Effective Strategies for Mitigating a Future Influenza Pandemic with H1N1 2009 Characteristics

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    Background: We performed an analysis of the cost-effectiveness of pandemic intervention strategies using a detailed, individual-based simulation model of a community in Australia together with health outcome data of infected individuals gathered during 2009–2010. The aim was to examine the cost-effectiveness of a range of interventions to determine the most cost-effective strategies suitable for a future pandemic with H1N1 2009 characteristics. Methodology/Principal Findings: Using transmissibility, age-stratified attack rates and health outcomes determined from H1N1 2009 data, we determined that the most cost-effective strategies involved treatment and household prophylaxis using antiviral drugs combined with limited duration school closure, with costs ranging from 632to632 to 777 per case prevented. When school closure was used as a sole intervention we found the use of limited duration school closure to be significantly more cost-effective compared to continuous school closure, a result with applicability to countries with limited access to antiviral drugs. Other social distancing strategies, such as reduced workplace attendance, were found to be costly due to productivity losses. Conclusion: The mild severity (low hospitalisation and case fatality rates) and low transmissibility of H1N1 2009 meant that health treatment costs were dominated by the higher productivity losses arising from workplace absence due to illness and childcare requirements following school closure. Further analysis for higher transmissibility but with the same, mild severit

    Evidence against a Human Cell-Specific Role for LRP6 in Anthrax Toxin Entry

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    The role of the cellular protein LRP6 in anthrax toxin entry is controversial. Previous studies showed that LRP6 was important for efficient intoxication of human M2182 prostate carcinoma cells but other studies performed with cells from gene-knockout mice demonstrated no role for either LRP6 or the related LRP5 protein in anthrax toxin entry. One possible explanation for this discrepancy is that LRP6 may be important for anthrax toxin entry into human, but not mouse, cells. To test this idea we have investigated the effect of knocking down LRP6 or LRP5 expression with siRNAs in human HeLa cells. We show here that efficient knockdown of either LRP6, LRP5, or both proteins has no influence on the kinetics of anthrax lethal toxin entry or MEK1 substrate cleavage in these cells. These data argue against a human-specific role for LRP6 in anthrax toxin entry and suggest instead that involvement of this protein may be restricted to certain cell types independently of their species of origin

    The Impact of Case Diagnosis Coverage and Diagnosis Delays on the Effectiveness of Antiviral Strategies in Mitigating Pandemic Influenza A/H1N1 2009

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    BACKGROUND: Neuraminidase inhibitors were used to reduce the transmission of pandemic influenza A/H1N1 2009 at the early stages of the 2009/2010 pandemic. Policies for diagnosis of influenza for the purposes of antiviral intervention differed markedly between and within countries, leading to differences in the timing and scale of antiviral usage. METHODOLOGY/PRINCIPAL FINDINGS: The impact of the percentage of symptomatic infected individuals who were diagnosed, and of delays to diagnosis, for three antiviral intervention strategies (each with and without school closure) were determined using a simulation model of an Australian community. Epidemic characteristics were based on actual data from the A/H1N1 2009 pandemic including reproduction number, serial interval and age-specific infection rate profile. In the absence of intervention an illness attack rate (AR) of 24.5% was determined from an estimated R(0) of 1.5; this was reduced to 21%, 16.5% or 13% by treatment-only, treatment plus household prophylaxis, or treatment plus household plus extended prophylaxis antiviral interventions respectively, assuming that diagnosis occurred 24 hours after symptoms arose and that 50% of symptomatic cases were diagnosed. If diagnosis occurred without delay, ARs decreased to 17%, 12.2% or 8.8% respectively. If 90% of symptomatic cases were diagnosed (with a 24 hour delay), ARs decreased to 17.8%, 11.1% and 7.6%, respectively. CONCLUSION: The ability to rapidly diagnose symptomatic cases and to diagnose a high proportion of cases was shown to improve the effectiveness of all three antiviral strategies. For epidemics with R(0)< = 1.5 our results suggest that when the case diagnosis coverage exceeds ∼70% the size of the antiviral stockpile required to implement the extended prophylactic strategy decreases. The addition of at least four weeks of school closure was found to further reduce cumulative and peak attack rates and the size of the required antiviral stockpile

    Analysis of the effectiveness of interventions used during the 2009 A/H1N1 influenza pandemic

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    <p>Abstract</p> <p>Background</p> <p>Following the emergence of the A/H1N1 2009 influenza pandemic, public health interventions were activated to lessen its potential impact. Computer modelling and simulation can be used to determine the potential effectiveness of the social distancing and antiviral drug therapy interventions that were used at the early stages of the pandemic, providing guidance to public health policy makers as to intervention strategies in future pandemics involving a highly pathogenic influenza strain.</p> <p>Methods</p> <p>An individual-based model of a real community with a population of approximately 30,000 was used to determine the impact of alternative interventions strategies, including those used in the initial stages of the 2009 pandemic. Different interventions, namely school closure and antiviral strategies, were simulated in isolation and in combination to form different plausible scenarios. We simulated epidemics with reproduction numbers R<sub>0</sub>of 1.5, which aligns with estimates in the range 1.4-1.6 determined from the initial outbreak in Mexico.</p> <p>Results</p> <p>School closure of 1 week was determined to have minimal effect on reducing overall illness attack rate. Antiviral drug treatment of 50% of symptomatic cases reduced the attack rate by 6.5%, from an unmitigated rate of 32.5% to 26%. Treatment of diagnosed individuals combined with additional household prophylaxis reduced the final attack rate to 19%. Further extension of prophylaxis to close contacts (in schools and workplaces) further reduced the overall attack rate to 13% and reduced the peak daily illness rate from 120 to 22 per 10,000 individuals. We determined the size of antiviral stockpile required; the ratio of the required number of antiviral courses to population was 13% for the treatment-only strategy, 25% for treatment and household prophylaxis and 40% for treatment, household and extended prophylaxis. Additional simulations suggest that coupling school closure with the antiviral strategies further reduces epidemic impact.</p> <p>Conclusions</p> <p>These results suggest that the aggressive use of antiviral drugs together with extended school closure may substantially slow the rate of influenza epidemic development. These strategies are more rigorous than those actually used during the early stages of the relatively mild 2009 pandemic, and are appropriate for future pandemics that have high morbidity and mortality rates.</p

    Simulation suggests that rapid activation of social distancing can arrest epidemic development due to a novel strain of influenza

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    <p>Abstract</p> <p>Background</p> <p>Social distancing interventions such as school closure and prohibition of public gatherings are present in pandemic influenza preparedness plans. Predicting the effectiveness of intervention strategies in a pandemic is difficult. In the absence of other evidence, computer simulation can be used to help policy makers plan for a potential future influenza pandemic. We conducted simulations of a small community to determine the magnitude and timing of activation that would be necessary for social distancing interventions to arrest a future pandemic.</p> <p>Methods</p> <p>We used a detailed, individual-based model of a real community with a population of approximately 30,000. We simulated the effect of four social distancing interventions: school closure, increased isolation of symptomatic individuals in their household, workplace nonattendance, and reduction of contact in the wider community. We simulated each of the intervention measures in isolation and in several combinations; and examined the effect of delays in the activation of interventions on the final and daily attack rates.</p> <p>Results</p> <p>For an epidemic with an R<sub>0 </sub>value of 1.5, a combination of all four social distancing measures could reduce the final attack rate from 33% to below 10% if introduced within 6 weeks from the introduction of the first case. In contrast, for an R<sub>0 </sub>of 2.5 these measures must be introduced within 2 weeks of the first case to achieve a similar reduction; delays of 2, 3 and 4 weeks resulted in final attack rates of 7%, 21% and 45% respectively. For an R<sub>0 </sub>of 3.5 the combination of all four measures could reduce the final attack rate from 73% to 16%, but only if introduced without delay; delays of 1, 2 or 3 weeks resulted in final attack rates of 19%, 35% or 63% respectively. For the higher R<sub>0 </sub>values no single measure has a significant impact on attack rates.</p> <p>Conclusion</p> <p>Our results suggest a critical role of social distancing in the potential control of a future pandemic and indicate that such interventions are capable of arresting influenza epidemic development, but only if they are used in combination, activated without delay and maintained for a relatively long period.</p

    Specification and Verification of Synchronous Hardware using LOTOS

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    This paper investigates specification and verification of synchronous circuits using DILL (Digital Logic in LOTOS). After an overview of the DILL approach, the paper focuses on the characteristics of synchronous circuits. A more constrained model is presented for specifying digital components and verifying them. Two standard benchmark circuits are specified using this new model, and analysed by the CADP toolset (Cæsar/Aldébaran Development Package)
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