3,373 research outputs found

    Undocumented Burden of Dengue in Africa

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    In Africa, information on dengue burden in Africa is limited. Dengue diagnostics is also a key challenge in defining the true burden. Among the various diagnostic options, rapid diagnostic test (RDT) is a convenient and prompt tool for dengue diagnosis, especially in resource-limited environments. To assess current knowledge on the use of RDTs for dengue with respect to their economic impact, a systematic review was conducted of published data. Overall, data were limited to demonstrate an economic impact of dengue RDTs and the available two studies reached different conclusions: one concluded that one particular RDT would be a cost-effective tool in endemic setting, and the other, based on a modeling, showed that a dengue RDT would not be advantageous in terms of cost and effectiveness compared to current practice of antibiotics prescription for undifferentiated fever. This thesis presents patterns of dengue epidemiology and outbreak based on passive fever surveillance studies in Mombasa, Kenya, and Ouagadougou, Burkina Faso. To estimate the proportion and understand clinical patterns of dengue-positive cases among non-malarial febrile patients, we conducted passive health facility-based fever surveillance studies in Ouagadougou, Burkina Faso and Mombasa, Kenya. In Mombasa, of 482 non-malarial febrile patients, 223 (46%) were identified as dengue– confirmed and 92 (19%) as dengue-probable. The surveillance covered the beginning of a dengue outbreak in April-May 2017, during which 67% of enrolled patients were dengue-confirmed. In Ouagadougou, of 2929 non-malarial febrile patients, 540 (18%) were identified as dengue–confirmed and 571 (19%) as dengue-probable. During the study period, a dengue outbreak occurred in September-November 2016, during which 46% of enrolled patients were dengue-confirmed. To understand DENV transmission in the community, 4 repeated serosurveys were conducted among the same individuals at 6 month intervals in Ouagadougou. Seroprevalence at enrollment was 66%. The binomial regression based on IgG positivity by age, assuming constant force of infection (FoI) over calendar time, resulted in the FOI of 6% per year. In summary, in both Burkina Faso and Kenya, there is considerable transmission of DENV, in terms of proportion of DENV confirmed infections among iii non-malarial febrile patients in the healthcare facilities as well as seroprevalence and FoI in the community. These burden estimates can facilitate evidence-based decision making on interventions for dengue prevention and control, including a dengue vaccine. However, given the currently available information on dengue burden in Africa and the status of dengue vaccine development, including the only licensed vaccine with restrictions in public health use, consideration of dengue vaccine introduction may be premature for Africa and more data would be necessary to build evidence base on dengue in African settings

    Quantifying interspecific variation in dispersal ability of noctuid moths using an advanced tethered flight technique

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    This is the final version. Available on open access from Wiley via the DOI in this recordDispersal plays a crucial role in many aspects of species' life histories, yet is often difficult to measure directly. This is particularly true for many insects, especially nocturnal species (e.g. moths) that cannot be easily observed under natural field conditions. Consequently, over the past five decades, laboratory tethered flight techniques have been developed as a means of measuring insect flight duration and speed. However, these previous designs have tended to focus on single species (typically migrant pests), and here we describe an improved apparatus that allows the study of flight ability in a wide range of insect body sizes and types. Obtaining dispersal information from a range of species is crucial for understanding insect population dynamics and range shifts. Our new laboratory tethered flight apparatus automatically records flight duration, speed, and distance of individual insects. The rotational tethered flight mill has very low friction and the arm to which flying insects are attached is extremely lightweight while remaining rigid and strong, permitting both small and large insects to be studied. The apparatus is compact and thus allows many individuals to be studied simultaneously under controlled laboratory conditions. We demonstrate the performance of the apparatus by using the mills to assess the flight capability of 24 species of British noctuid moths, ranging in size from 12-27 mm forewing length (~40-660 mg body mass). We validate the new technique by comparing our tethered flight data with existing information on dispersal ability of noctuids from the published literature and expert opinion. Values for tethered flight variables were in agreement with existing knowledge of dispersal ability in these species, supporting the use of this method to quantify dispersal in insects. Importantly, this new technology opens up the potential to investigate genetic and environmental factors affecting insect dispersal among a wide range of species.Rothamsted Research receives grant aided support from the Biotechnology and Biological Sciences Research Council. H.B.C.J. was funded by a BBSRC Quota studentship awarded to J.W.C. and J.K.H

    Bioactivity-Guided Isolation of Anticancer Agents from Bauhinia Kockiana Korth.

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    Background: Flowers of Bauhinia kockiana were investigated for their anticancer properties.Methods: Gallic acid (1), and methyl gallate (2), were isolated via bioassay-directed isolation, and they exhibited anticancer properties towards several cancer cell lines, examined using MTT cell viability assay. Pyrogallol (3) was examined against the same cancer cell lines to deduce the bioactive functional group of the phenolic compounds.Results: The results showed that the phenolic compounds could exhibit moderate to weak cytotoxicity towards certain cell lines (GI50 30 - 86 μM), but were inactive towards DU145 prostate cancer cell (GI50 > 100 μM).Conclusion: It was observed that pyrogallol moiety was one of the essential functional structures of the phenolic compounds in exhibiting anticancer activity. Also, the carboxyl group of compound 1 was also important in anticancer activity. Examination of the PC-3 cells treated with compound 1 using fluorescence microscopy showed that PC-3 cells were killed by apoptosis.Key words: Gallic acid; Bauhinia kockiana; pyrogallol; anticancer; apoptosis

    Thermoelectric properties of Al-doped mesoporous ZnO thin films

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    Al-doped mesoporous ZnO thin films were synthesized by a sol-gel process and an evaporation-induced self-assembly process. In this work, the effects of Al doping concentration on the electrical conductivity and characterization of mesoporous ZnO thin films were investigated. By changing the Al doping concentration, ZnO grain growth is inhibited, and the mesoporous structure of ZnO is maintained during a relatively high temperature annealing process. The porosity of Al-doped mesoporous ZnO thin films increased slightly with increasing Al doping concentration. Finally, as electrical conductivity was increased as electrons were freed and pore structure was maintained by inhibiting grain growth, the thermoelectric property was enhanced with increasing Al concentration. © 2013 Min-Hee Hong et al

    Longitudinal Study to Assess the Quantitative Use of Fundus Autofluorescence for Monitoring Disease Progression in Choroideremia

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    BACKGROUND: Characterisation of preserved autofluorescence (PAF) area in choroideremia (CHM) and its validity for monitoring disease progression in clinical trials is of importance. METHODS: Eighty patients with molecularly confirmed CHM were recruited. PAF area was measured manually by 2 graders and half-life was calculated based on exponential decay model. RESULTS: Mean age at baseline and follow-up examination was 38.1 (range, 10-69) and 40.7 (range, 11-70) years. Mean follow-up interval was 29 months (range, 6-104). The median LogMAR visual acuity was 0.10 (OD) and 0.18 (OS). Interobserver repeatability for PAF area was -0.99 to 1.03 mm2 (-6.46 to 6.49% of area). There was a statistically significant relationship between age and rate of PAF area loss (r2 = 0.28, p = 0.012). The half-life for PAF area was 13.7 years (range, 1.7-216.0 years). The correlation between half-life and age was stronger than between half-life and log transformed baseline PAF area, although neither was statistically significant. CONCLUSIONS: The intra- and inter-observer PAF area measurement variability provides a baseline change, which must be overcome in a clinical trial if this metric were to be used. Treatments must slow progression to alter the exponential decay in a timely manner accounting for naturally slow progression patterns

    Longitudinal Study to Assess the Quantitative Use of Fundus Autofluorescence for Monitoring Disease Progression in Choroideremia

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    BACKGROUND: Characterisation of preserved autofluorescence (PAF) area in choroideremia (CHM) and its validity for monitoring disease progression in clinical trials is of importance. METHODS: Eighty patients with molecularly confirmed CHM were recruited. PAF area was measured manually by 2 graders and half-life was calculated based on exponential decay model. RESULTS: Mean age at baseline and follow-up examination was 38.1 (range, 10-69) and 40.7 (range, 11-70) years. Mean follow-up interval was 29 months (range, 6-104). The median LogMAR visual acuity was 0.10 (OD) and 0.18 (OS). Interobserver repeatability for PAF area was -0.99 to 1.03 mm2 (-6.46 to 6.49% of area). There was a statistically significant relationship between age and rate of PAF area loss (r2 = 0.28, p = 0.012). The half-life for PAF area was 13.7 years (range, 1.7-216.0 years). The correlation between half-life and age was stronger than between half-life and log transformed baseline PAF area, although neither was statistically significant. CONCLUSIONS: The intra- and inter-observer PAF area measurement variability provides a baseline change, which must be overcome in a clinical trial if this metric were to be used. Treatments must slow progression to alter the exponential decay in a timely manner accounting for naturally slow progression patterns

    Effect of surfactant concentration variation on the thermoelectric properties of mesoporous ZnO

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    The electrical and thermal conductivities and the Seebeck coefficient of mesoporous ZnO thin films were investigated to determine the change of their thermoelectric properties by controlling surfactant concentration in the mesoporous ZnO films, because the thermoelectric properties of mesoporous ZnO films can be influenced by the porosity of the mesoporous structures, which is primarily determined by surfactant concentration in the films. Mesoporous ZnO thin films were successfully synthesized by using sol-gel and evaporation-induced self-assembly processes. Zinc acetate dihydrate and Brij-76 were used as the starting material and pore structure-forming template, respectively. The porosity of mesoporous ZnO thin films increased from 29% to 40% with increasing surfactant molar ratio. Porosity can be easily altered by controlling the molar ratio of surfactant/precursor. The electrical and thermal conductivity and Seebeck coefficients showed a close correlation with the porosity of the films, indicating that the thermoelectric properties of thin films can be changed by altering their porosity. Mesoporous ZnO thin films with the highest porosity had the best thermoelectric properties (the lowest thermal conductivity and the highest Seebeck coefficient) of the films examined. © 2013 Min-Hee Hong et al

    Fracture Liaison Service and Its Role in Secondary Fracture Prevention in Malaysia: A Scoping Review

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    Introduction: Fragility fractures, which occur after a low- trauma injury, increases with advancing age. Such fracture doubles the life-time risk of sustaining another fracture. This risk is highest in the immediate 18 months after the index fracture. However, most patients do not receive the appropriate risk assessment and intervention to reduce this risk. A coordinated model of care termed Fracture Liaison Service (FLS) has been reported to address this treatment gap. Materials and methods: This scoping review aims to explore the potential role and delivery of FLS services in Malaysia. Scientific and non-scientific sources relevant to FLS were identified from electronic bibliographic databases, specialist journals and relevant websites. Findings were categorised into themes and presented narratively. Results: FLS services remain concentrated in the Klang Valley. Even within FLS services, many do not have extensive coverage to risk assess all fracture patients. These services are multidisciplinary in nature where there are links between different departments, such as orthopaedics, osteoporosis expertise, bone densitometry, rehabilitation, falls services and primary care. FLS was able to increase the number of people undergoing fracture risk assessment and treatment. The importance of FLS was highlighted by local experts and stakeholders. Its implementation and delivery are supported by a number of national guidelines. Conclusion: FLS is central to our national efforts to reduce the impending fragility fracture crisis in the coming years. Continued effort is needed to increase coverage within FLS services and across the country. Training, awareness of the problem, research, and policy change will support this endeavour

    Evidence for a pervasive 'idling-mode' activity template in flying and pedestrian insects

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    This is the final version. Available on open access from the Royal Society via the DOI in this recordUnderstanding the complex movement patterns of animals in natural environments is a key objective of 'movement ecology'. Complexity results from behavioural responses to external stimuli but can also arise spontaneously in their absence. Drawing on theoretical arguments about decision-making circuitry, we predict that the spontaneous patterns will be scale-free and universal, being independent of taxon and mode of locomotion. To test this hypothesis, we examined the activity patterns of the European honeybee, and multiple species of noctuid moth, tethered to flight mills and exposed to minimal external cues. We also reanalysed pre-existing data for Drosophila flies walking in featureless environments. Across these species, we found evidence of common scale-invariant properties in their movement patterns; pause and movement durations were typically power law distributed over a range of scales and characterized by exponents close to 3/2. Our analyses are suggestive of the presence of a pervasive scale-invariant template for locomotion which, when acted on by environmental cues, produces the movements with characteristic scales observed in nature. Our results indicate that scale-finite complexity as embodied, for instance, in correlated random walk models, may be the result of environmental cues overriding innate behaviour, and that scale-free movements may be intrinsic and not limited to 'blind' foragers as previously thought.Rothamsted research receives grant aided support from the Biotechnology and Biological Sciences Research Council. S.W. was funded jointly by a grant from BBSRC, Defra, NERC, the Scottish Government and the Wellcome Trust, under the Insect Pollinators Initiative (grant nos. BB/I00097/1). A.J.P. was funded by a BBSRC Doctoral Training Partnership in Food Security awarded to K.W. and J.W.C. H.B.C.J. was funded by a BBSRC Quota studentship awarded to J.W.C. and J.K.
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