57 research outputs found

    Discordant Immune Response with Antiretroviral Therapy in HIV-1: A Systematic Review of Clinical Outcomes.

    Get PDF
    BACKGROUND A discordant immune response (DIR) is a failure to satisfactorily increase CD4 counts on ART despite successful virological control. Literature on the clinical effects of DIR has not been systematically evaluated. We aimed to summarise the risk of mortality, AIDS and serious non-AIDS events associated with DIR with a systematic review. METHODS The protocol is registered with the Centre for Review Dissemination, University of York (registration number CRD42014010821). Included studies investigated the effect of DIR on mortality, AIDS, or serious non-AIDS events in cohort studies or cohorts contained in arms of randomised controlled trials for adults aged 16 years or older. DIR was classified as a suboptimal CD4 count (as defined by the study) despite virological suppression following at least 6 months of ART. We systematically searched PubMed, Embase, and the Cochrane Library to December 2015. Risk of bias was assessed using the Cochrane tool for assessing risk of bias in cohort studies. Two authors applied inclusion criteria and one author extracted data. Risk ratios were calculated for each clinical outcome reported. RESULTS Of 20 studies that met the inclusion criteria, 14 different definitions of DIR were used. Risk ratios for mortality in patients with and without DIR ranged between 1.00 (95% CI 0.26 to 3.92) and 4.29 (95% CI 1.96 to 9.38) with the majority of studies reporting a 2 to 3 fold increase in risk. CONCLUSIONS DIR is associated with a marked increase in mortality in most studies but definitions vary widely. We propose a standardised definition to aid the development of management options for DIR

    User Needs Assessment of Information Seeking Activities of MIT Students - Spring 2006

    Get PDF
    The SFX/Verde Group was authorized to complete a user needs assessment in the form of a Photo Diary Study with MIT students in the spring of 2006. The goal of the study was to inform the MIT Libraries of online tool improvements that should be implemented to meet our most pressing user needs. Sixteen graduate students and sixteen undergraduate students participated in offering a fascinating glimpse into the information-seeking aspects of their academic lives. The team categorized user behaviors into goals and tasks and then analyzed the 277 goals and tasks and the 507 methods shared with us by the students in the study. The study yielded the following priorities for the Libraries' online tools: Make discovery easier and more effective. Incorporate trusted networks in finding tools. Continue to put links to the Libraries' services and resources where the users are. The study also showed that the students used a variety of highly successful strategies for performing quick lookups of information and finding specific known items. Finally, while the assessment focused on aspects of the students' work related to online tools, it also yielded rich information that could be useful in improving other aspects of the Libraries' services

    Acción : diario de Teruel y su provincia: Año II Número 116 - (06/04/33)

    Get PDF
    The selective aerobic oxidation of crotyl alcohol to crotonaldehyde was investigated by time-resolved synchronous DRIFTS/MS/XAS over silica and alumina supported Pd nanoparticles. Alcohol and oxygen reactant feeds were cycled through the catalyst bed while dynamic measurements of the palladium oxidation state, molecular adsorbates and evolved product distribution were made simultaneously on a sub-second timescale. Highly dispersed palladium nanoparticles remained in a partially oxidised state <100 degrees C, independent of the redox environment, and were selective for crotonaldehyde formation. Higher temperatures facilitated rapid catalyst reduction on exposure to crotyl alcohol, with palladium metal driving crotonaldehyde decarbonylation to propene and CO, while slower (surface diffusion-limited) reoxidation on exposure to oxygen re-opened selective oxidation pathways. Surface palladium oxide is identified as the desired active species

    Tailored metal nanoparticles for selective catalysis

    Get PDF
    The development of clean, sustainable chemical processes is a key priority towards meeting the growing demand for synthetic functional chemicals, while balancing rapidly depleting natural resources. The selective oxidation (selox) of crotyl alcohol to crotonaldehyde and the selective hydrogenation of benzyl cyanide to phenylethylamine are two specific systems for which, it is proposed, new heterogeneous catalysts and deeper mechanistic insight will improve. In this thesis the rational design of palladium catalysts is investigated for these systems, via synthesis of palladium nanoparticles with tailored morphology and palladium-gold nanoparticles with tuneable surface composition. Pd icosahedra, nanorods and nanocubes were synthesised and characterised extensively to confirm the size and morphology of the nanoparticles. Pd icosahedra are revealed to be three times more active for crotyl alcohol selox than the nanocubes, and ten times faster than the nanorods, while maintaining good selectivity. An Au-shell, Pd-core structure was synthesised, progressively annealed to induce alloying and characterised using various in situ spectroscopies. Surface Au was found to enhance crotyl alcohol selox activity and selectivity towards crotonaldehyde, in accordance with model predictions. An optimum crotonaldehyde yield was obtained for an Au40Pd60 surface alloy. By employing in situ and time-resolved spectroscopies the active site of Pd selox catalysts is examined, and the role of oxygen in this system and the catalyst’s kinetic behaviour is defined. Reversible redox cycling of the catalyst dependent on its environment was observed, and it was possible to identify PdOx as the active catalytic species responsible for selectively oxidising crotyl alcohol to crotonaldehyde, with high temperatures suppressing catalytic selectivity. Systematic characterisation of an industrial carbon supported Pd catalyst, used in nitrile hydrogenation, reveals potential sources of deactivation including surface poisoning by CN species. Solutions to improve catalyst performance are proposed using the knowledge acquired from the nanoparticle catalysts’ studies

    Identifying lifestyle factors associated to co-morbidity of obesity and psychiatric disorders, a pilot study

    Get PDF
    Obesity and psychiatric disorders are linked through a bidirectional association. Obesity rates have tripled globally in the past decades, and it is predicted that by 2025, one billion people will be affected by obesity, often with a co-morbidity such as depression. While this co-morbidity seems to be a global health issue, lifestyle factors associated to it differ between countries and are often attributed to more than one factor. Prior obesity studies were performed in Western populations; this is the first study that investigates lifestyle factors relating to obesity and mental health of the diverse population in Qatar, a country that has witnessed tremendous lifestyle change in a short time. In this pilot study, we surveyed 379 respondents to assess and compare the lifestyles of Qatar residents to the global population. However due to the high proportion of responses from the United Kingdom (UK) residents, we have made comparisons between Qatar residents and UK residents. We used chi-square analysis, spearman rank correlation and logistic regression to compare the lifestyle factors of individuals suffering from both increased BMI and mental health conditions. The types of food consumed, stress, exercise frequency and duration, alcohol and tobacco consumption, and sleep duration, were explored and results argue that different lifestyle factors can contribute to the same health condition, suggesting different mechanisms involved. We found that both groups reported similar sleep durations (p = 0.800), but that perception of sleep (p = 0.011), consumption of alcohol (p = 0.001), consumption of takeaway food (p = 0.007), and physical activity significantly varied between the groups (p = 0.0001). The study examined the predictors of comorbidity in Qatar as well as UK populations using multivariate logistic regression analysis. The result of the study showed no statistical association between comorbidity and the predictors drinking habit, smoking, physical activity, vegetable consumption, eat outs, and sleep perception for the Qatar population, and for the combined population. This study, however showed a significant association (p = 0.033) between sleep perception and comorbidity for the UK population. We conclude that further analysis is needed to understand the relationship between specific lifestyle factors and multimorbidity in each country

    Ophthalmic features of HIV associated cryptococcal meningitis in Malawian Adults: an observational study

    Get PDF
    Background: Cryptococcal meningitis (CM) is the commonest neurological complication in patients with advanced HIV. Visual disturbance is a frequent presenting symptom. Papilloedema is commonly reported but other ophthalmic findings are not well described. Methods: We performed an observational study comparing severely immunocompromised HIV-infected patients with and without CM to determine the nature and prevalence of retinal pathology attributable to CM. 70 adult patients were enrolled in Blantyre Malawi, 35 with CM and 35 HIV-infected patients without CM. Results: 79% (19/24) of CM patients examined on day one had evidence of retinal abnormalities compared to 17% (6/35) of HIV-infected controls (p <0.001). In the CM group, retinal whitening was the commonest abnormality (50%), followed by optic disc swelling (29%), haemorrhage (25%) and vascular abnormalities (7%). Retinal whitening was the only abnormality observed in the comparator group (17%). In CM, there was no significant difference between those with and without retinal abnormalities in fungal burden (13,550 cfu/ml vs. 9,150 cfu/ml; p = 0.65), CD4 count (28 cells/µl vs. 76 cells/µl; p = 0.79) or CSF opening pressure (21cm H20 vs. 27cm H20; p = 0.5).  There was no association between presence/absence of retinal abnormalities and death (40% 10-week mortality vs. 26%; p = 0.6). Conclusions: Whether the presence of CM retinopathy could be used as a marker of disease severity warrants further investigation. The observed ophthalmic findings provide a descriptive framework for CM retinopathy to be utilised in future CM studies. Trial registration: ISRCTN ( ISRCTN45035509 ) 19/06/2012

    Stable Isotope Biogeochemistry of Seabird Guano Fertilization: Results from Growth Chamber Studies with Maize (Zea Mays)

    Get PDF
    Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ(15)N). Animal excrement is known to impact plant δ(15)N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.This paper presents isotopic (δ(13)C and δ(15)N) and vital data for maize (Zea mays) fertilized with Peruvian seabird guano under controlled conditions. The level of (15)N enrichment in fertilized plants is very large, with δ(15)N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ(15)N values ranged between -0.3 and 5.7‰. Intraplant and temporal variability in δ(15)N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ(13)C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk.The results presented in this study demonstrate the very large impact of seabird guano on maize δ(15)N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs). Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level marine resource, which must be considered when interpreting isotopic data from archaeological material

    Qualitative impact assessment of land management interventions on ecosystem services ("QEIA"). Report-1: executive summary QEIA evidence review & integrated assessment

    Get PDF
    The focus of this project was to provide a rapid qualitative assessment of land management interventions on Ecosystem Services (ES) proposed for inclusion in Environmental Land Management (ELM) schemes. This involved a review of the current evidence base by ten expert teams drawn from the independent research community in a consistent series of ten Evidence Reviews. These reviews were undertaken rapidly at Defra’s request and together captured more than 2000 individual sources of evidence. These reviews were then used to inform an Integrated Assessment (IA) to provide a more accessible summary of these evidence reviews with a focus on capturing the actions with the greatest potential magnitude of change for the intended ES and their potential co-benefits and trade-offs across the Ecosystem Services and Ecosystem Services Indicators. The final IA table captured scores for 741 actions across 8 Themes, 33 ES and 53 ES-indicators. This produced a total possible matrix of 39,273 scores. It should be noted that this piece of work is just one element of the wider underpinning work Defra has commissioned to support the development of the ELM schemes. The project was carried out in two phases with the environmental and provisioning services commissioned in Phase 1 and cultural and regulatory services in a follow-on Phase 2. Due to the urgency of the need for these evidence reviews, there was insufficient time for systematic reviews and therefore the reviews relied on the knowledge of the team of the peer reviewed and grey literature with some rapid additional checking of recent reports and papers. This limitation of the review process was clearly explained and understood

    Qualitative impact assessment of land management interventions on ecosystem services (‘QEIA’). Report-2: integrated assessment

    Get PDF
    This project assessed the impacts of 741 potential land management actions, suitable for agricultural land in England, on the Farming & Countryside Programme’s Environmental Objectives (and therefore Environment Act targets and climate commitments) through 53 relevant environmental and cultural service indicators. The project used a combination of expert opinion and rapid evidence reviews, which included 1000+ pages of evidence in 10 separate reports with reference to over 2400 published studies, and an Integrated Assessment comprising expert-derived qualitative impact scores. The project has ensured that ELM schemes are evidence-based, offer good value for money, and contribute to SoS priorities for farming
    corecore