129 research outputs found

    Tools for delivering entomopathogenic fungi to malaria mosquitoes: effects of delivery surfaces on fungal efficacy and persistence.

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    BACKGROUND\ud \ud Entomopathogenic fungi infection on malaria vectors increases daily mortality rates and thus represents a control measure that could be used in integrated programmes alongside insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS). Before entomopathogenic fungi can be integrated into control programmes, an effective delivery system must be developed.\ud \ud METHODS\ud \ud The efficacy of Metarhizium anisopliae ICIPE-30 and Beauveria bassiana I93-825 (IMI 391510) (2 Γ— 10(10) conidia m(-2)) applied on mud panels (simulating walls of traditional Tanzanian houses), black cotton cloth and polyester netting was evaluated against adult Anopheles gambiae sensu stricto. Mosquitoes were exposed to the treated surfaces 2, 14 and 28 d after conidia were applied. Survival of mosquitoes was monitored daily.\ud \ud RESULTS\ud \ud All fungal treatments caused a significantly increased mortality in the exposed mosquitoes, descending with time since fungal application. Mosquitoes exposed to M. anisopliae conidia on mud panels had a greater daily risk of dying compared to those exposed to conidia on either netting or cotton cloth (p < 0.001). Mosquitoes exposed to B. bassiana conidia on mud panels or cotton cloth had similar daily risk of death (p = 0.14), and a higher risk than those exposed to treated polyester netting (p < 0.001). Residual activity of fungi declined over time; however, conidia remained pathogenic at 28 d post application, and were able to infect and kill 73 - 82% of mosquitoes within 14 d.\ud \ud CONCLUSION\ud \ud Both fungal isolates reduced mosquito survival on immediate exposure and up to 28 d after application. Conidia were more effective when applied on mud panels and cotton cloth compared with polyester netting. Cotton cloth and mud, therefore, represent potential substrates for delivering fungi to mosquitoes in the field

    Rapid response of Helheim Glacier in Greenland to climate variability over the past century

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    Author Posting. Β© The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 5 (2012): 37-41, doi:10.1038/ngeo1349.During the early 2000s the Greenland Ice Sheet experienced the largest ice mass loss observed on the instrumental record1, largely as a result of the acceleration, thinning and retreat of major outlet glaciers in West and Southeast Greenland2-5. The quasi-simultaneous change in the glaciers suggests a common climate forcing and increasing air6 and ocean7-8 temperatures have been indicated as potential triggers. Here, we present a new record of calving activity of Helheim Glacier, East Greenland, extending back to c. 1890 AD. This record was obtained by analysing sedimentary deposits from Sermilik Fjord, where Helheim Glacier terminates, and uses the annual deposition of sand grains as a proxy for iceberg discharge. The 120 year long record reveals large fluctuations in calving rates, but that the present high rate was reproduced only in the 1930s. A comparison with climate indices indicates that high calving activity coincides with increased Atlantic Water and decreased Polar Water influence on the shelf, warm summers and a negative phase of the North Atlantic Oscillation. Our analysis provides evidence that Helheim Glacier responds to short-term (3-10 years) large-scale oceanic and atmospheric fluctuations.This study has been supported by Geocenter Denmark in financial support to the SEDIMICE project. CSA was supported by the Danish Council for Independent Researchβ”‚Nature and Universe (Grant no. 09-064954/FNU). FSt was supported by NSF ARC 0909373 and by WHOI’s Ocean and Climate Change Institute and MHRI was supported by the Danish Agency for Science, Technology and Innovation.2012-06-1

    The dynamic stator stalk of rotary ATPases

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    Rotary ATPases couple ATP hydrolysis/synthesis with proton translocation across biological membranes and so are central components of the biological energy conversion machinery. Their peripheral stalks are essential components that counteract torque generated by rotation of the central stalk during ATP synthesis or hydrolysis. Here we present a 2.25-Γ… resolution crystal structure of the peripheral stalk from Thermus thermophilus A-type ATPase/synthase. We identify bending and twisting motions inherent within the structure that accommodate and complement a radial wobbling of the ATPase headgroup as it progresses through its catalytic cycles, while still retaining azimuthal stiffness necessary to counteract rotation of the central stalk. The conformational freedom of the peripheral stalk is dictated by its unusual right-handed coiled-coil architecture, which is in principle conserved across all rotary ATPases. In context of the intact enzyme, the dynamics of the peripheral stalks provides a potential mechanism for cooperativity between distant parts of rotary ATPases

    Freezing of gait and fall detection in Parkinson’s disease using wearable sensors:a systematic review

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    Despite the large number of studies that have investigated the use of wearable sensors to detect gait disturbances such as Freezing of gait (FOG) and falls, there is little consensus regarding appropriate methodologies for how to optimally apply such devices. Here, an overview of the use of wearable systems to assess FOG and falls in Parkinson’s disease (PD) and validation performance is presented. A systematic search in the PubMed and Web of Science databases was performed using a group of concept key words. The final search was performed in January 2017, and articles were selected based upon a set of eligibility criteria. In total, 27 articles were selected. Of those, 23 related to FOG and 4 to falls. FOG studies were performed in either laboratory or home settings, with sample sizes ranging from 1 PD up to 48 PD presenting Hoehn and Yahr stage from 2 to 4. The shin was the most common sensor location and accelerometer was the most frequently used sensor type. Validity measures ranged from 73–100% for sensitivity and 67–100% for specificity. Falls and fall risk studies were all home-based, including samples sizes of 1 PD up to 107 PD, mostly using one sensor containing accelerometers, worn at various body locations. Despite the promising validation initiatives reported in these studies, they were all performed in relatively small sample sizes, and there was a significant variability in outcomes measured and results reported. Given these limitations, the validation of sensor-derived assessments of PD features would benefit from more focused research efforts, increased collaboration among researchers, aligning data collection protocols, and sharing data sets

    Variation in the provision and practice of implant-based breast reconstruction in the UK: Results from the iBRA national practice questionnaire

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    Introduction The introduction of biological and synthetic meshes has revolutionised the practice of implant-based breast reconstruction (IBBR) but evidence for effectiveness is lacking. The iBRA (implant Breast Reconstruction evAluation) study is a national trainee-led project that aims to explore the practice and outcomes of IBBR to inform the design of a future trial. We report the results of the iBRA National Practice Questionnaire (NPQ) which aimed to comprehensively describe the provision and practice of IBBR across the UK. Methods A questionnaire investigating local practice and service provision of IBBR developed by the iBRA Steering Group was completed by trainee and consultant leads at breast and plastic surgical units across the UK. Summary data for each survey item were calculated and variation between centres and overall provision of care examined. Results 81 units within 79 NHS-hospitals completed the questionnaire. Units offered a range of reconstructive techniques, with IBBR accounting for 70% (IQR:50–80%) of participating units' immediate procedures. Units on average were staffed by 2.5 breast surgeons (IQR:2.0–3.0) and 2.0 plastic surgeons (IQR:1.0–3.0) performing 35 IBBR cases per year (IQR:20-50). Variation was demonstrated in the provision of novel different techniques for IBBR especially the use of biological (n = 62) and synthetic (n = 25) meshes and in patient selection for these procedures. Conclusions The iBRA-NPQ has demonstrated marked variation in the provision and practice of IBBR in the UK. The prospective audit phase of the iBRA study will determine the safety and effectiveness of different approaches to IBBR and allow evidence-based best practice to be explored

    Biological soil crusts of Arctic Svalbard and of Livingston Island, Antarctica

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    Biological soil crusts (BSCs) occur in arid and semi-arid regions worldwide including the Polar Regions. They are important ecosystem engineers, and their composition and areal coverage should be understood before assessing key current functional questions such as their role in biogeochemical nutrient cycles and possible climate change scenarios. Our aim was to investigate the variability of BSCs from Arctic Svalbard and the Antarctic Island, Livingston, using vegetation surveys based on classification by functional group. An additional aim was to describe the structure of BSCs and represent a classification system that can be used in future studies to provide a fast and efficient way to define vegetation type and areal coverage. Firstly, this study demonstrates huge areas occupied by BSCs in Arctic Svalbard, with up to 90 % of soil surface covered, dominated by bryophytes and cyanobacteria, and showing an unexpectedly high variability in many areas. Livingston Island has lower percentage coverage, up to 55 %, but is dominated by lichens. Our findings show that both Polar Regions have varied BSC coverage, within the sites and between them, especially considering their harsh climates and latitudinal positions. Secondly, we have classified the BSCs of both areas into a system that describes the dominant functional groups and local geography, creating a simple scheme that allows easy identification of the prevailing vegetation type. Our results represent the first contribution to the description of BSCs based on their functional group composition in Polar Regions

    Rapid Changes in the Light/Dark Cycle Disrupt Memory of Conditioned Fear in Mice

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    Background: Circadian rhythms govern many aspects of physiology and behavior including cognitive processes. Components of neural circuits involved in learning and memory, e.g., the amygdala and the hippocampus, exhibit circadian rhythms in gene expression and signaling pathways. The functional significance of these rhythms is still not understood. In the present study, we sought to determine the impact of transiently disrupting the circadian system by shifting the light/ dark (LD) cycle. Such β€˜β€˜jet lag’ ’ treatments alter daily rhythms of gene expression that underlie circadian oscillations as well as disrupt the synchrony between the multiple oscillators found within the body. Methodology/Principal Findings: We subjected adult male C57Bl/6 mice to a contextual fear conditioning protocol either before or after acute phase shifts of the LD cycle. As part of this study, we examined the impact of phase advances and phase delays, and the effects of different magnitudes of phase shifts. Under all conditions tested, we found that recall of fear conditioned behavior was specifically affected by the jet lag. We found that phase shifts potentiated the stress-evoked corticosterone response without altering baseline levels of this hormone. The jet lag treatment did not result in overall sleep deprivation, but altered the temporal distribution of sleep. Finally, we found that prior experience of jet lag helps to compensate for the reduced recall due to acute phase shifts. Conclusions/Significance: Acute changes to the LD cycle affect the recall of fear-conditioned behavior. This suggests that

    Inhibition of Neuroblastoma Tumor Growth by Targeted Delivery of MicroRNA-34a Using Anti-Disialoganglioside GD2 Coated Nanoparticles

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    Neuroblastoma is one of the most challenging malignancies of childhood, being associated with the highest death rate in paediatric oncology, underlining the need for novel therapeutic approaches. Typically, patients with high risk disease undergo an initial remission in response to treatment, followed by disease recurrence that has become refractory to further treatment. Here, we demonstrate the first silica nanoparticle-based targeted delivery of a tumor suppressive, pro-apoptotic microRNA, miR-34a, to neuroblastoma tumors in a murine orthotopic xenograft model. These tumors express high levels of the cell surface antigen disialoganglioside GD2 (GD(2)), providing a target for tumor-specific delivery.Nanoparticles encapsulating miR-34a and conjugated to a GD(2) antibody facilitated tumor-specific delivery following systemic administration into tumor bearing mice, resulted in significantly decreased tumor growth, increased apoptosis and a reduction in vascularisation. We further demonstrate a novel, multi-step molecular mechanism by which miR-34a leads to increased levels of the tissue inhibitor metallopeptidase 2 precursor (TIMP2) protein, accounting for the highly reduced vascularisation noted in miR-34a-treated tumors.These novel findings highlight the potential of anti-GD(2)-nanoparticle-mediated targeted delivery of miR-34a for both the treatment of GD(2)-expressing tumors, and as a basic discovery tool for elucidating biological effects of novel miRNAs on tumor growth

    Rituximab for the First-Line Maintenance Treatment of Follicular Non-Hodgkin’s Lymphoma

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    The National Institute for Health and Clinical Excellence (NICE) invited the manufacturer of rituximab (RTX) [Roche] to submit evidence for the clinical and cost effectiveness of RTX as first-line maintenance treatment for patients with follicular non-Hodgkin’s lymphoma (fNHL) whose disease has responded to induction therapy with RTX plus cytotoxic chemotherapy (R-CTX) in accordance with the Institute’s Single Technology Appraisal (STA) process. The Liverpool Reviews and Implementation Group (LRiG) at the University of Liverpool was commissioned to act as the Evidence Review Group (ERG). This article summarizes the ERG’s review of the evidence submitted by the manufacturer and provides a summary of the Appraisal Committee’s (AC) decision. The clinical evidence was derived from a multi-centred, open-label, randomized phase III study (PRIMA) comparing first-line maintenance treatment with RTX with observation only in 1,018 patients with previously untreated advanced fNHL. Median time to event (MTE) for the primary endpoint of progression-free survival (PFS) in the RTX arm was not estimable due to data immaturity; median PFS in the observation arm was 48.36Β months. A statistically significant benefit of RTX maintenance therapy for PFS was reported (hazard ratio [HR] 0.55, 95Β % CI 0.44–0.68; pΒ <Β 0.0001). Statistically significant differences in favour of RTX were also reported for a range of secondary endpoints. Assessment of overall survival benefit could be not made due to insufficient events. The ERG’s main concern with the clinical-effectiveness data presented was their lack of maturity. The submitted incremental cost-effectiveness ratio was within the NICE threshold. The ERG questioned the model on a number of grounds, particularly the use of Markov methodology rather than patient simulations, the impact of patient age on the outcome and the projective PFS modelling. The ERG considered it impossible to draw firm conclusions regarding the clinical or cost effectiveness of the intervention as the dataset was as yet too immature. At a third meeting, the AC concluded that RTX could be recommended as first-line maintenance treatment for patients with fNHL whose disease has responded to induction R-CTX
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