17 research outputs found

    Intestinal myiasis in a Malaysian patient caused by larvae of Clogmia albipunctatus (Diptera: Psychodidae)

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    Clogmia albipunctatus (Duckhouse) is a cosmopolitan fly belonging to the family Psychodidae and is one of the medically important insects associated with urban environments ( Smith and Thomas 1979 ). Psychodid larvae can cause myiasis in humans through infestation of healthy or traumatized tissues ( Hall and Smith 1993 ). Human myiasis can be presented in various forms with cutaneous myiasis the most common form ( Tu et al. 2007 ). Other infestation sites include nasal, aural, pulmonary, ophthalmic cavities, body cavities, and the gastrointestinal and urogenital systems ( Tu et al. 2007 , El-Badry et al. 2014 ). Intestinal myiasis may result from accidental ingestion of larvae. Subsequently, this form of myiasis presents symptoms such as nausea, vomiting, abdominal pain and distention, loss of appetite, weight loss, and episodic diarrhea ( Ramana 2012 ). This is the second reported case of human intestinal myiasis in Malaysia caused by larvae of C. albipunctatus . Microscopic examination revealed the structure of the larvae and DNA barcoding established the species identity

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Waste quantification models for estimation of construction and demolition waste generation: a review

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    Quantification is crucial for construction and demolition waste management. Accurate estimation can be satisfied by developing waste quantification model that is applicable for regional or nation-wide C&D waste generation. This paper presents a review on quantification models for C&D waste from literatures and how they correlate. Most studies combine the empirical waste assessment data or waste generation factor obtained in the field with area of activity level extracted from national statistical database from their respective countries, which provides annual data on sector activities. National or regional estimates provide general figures and forecasts for annual C&D waste generation. Studies found that waste generation factor will differs according to locations. Since volume and characteristic of waste are crucial for waste quantification, quantitative data record from waste audit findings could benefit the authorities for the annual estimates. National C&D waste reduction plan should start from well-established waste minimisation plan at project sites. Copyright © 2012 Inderscience Enterprises Ltd

    Impact of spatial variability in microfabrics on heat transfer characteristics of some sedimentary rocks

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    Heat flow studies in geological systems are of paramount interest to the oil and gas industry. Such studies give an indication on the thermal maturity of the hydrocarbon reserves and also provide a better enhanced understanding of the reservoir. The ongoing study on the geological Formations in Northern Sarawak has indicated the need to reevaluate the heat flow characteristics of the sedimentary rocks in the area. This need was a direct manifestation of strong discrepancies between the results and trends published by previous workers in the region.The Belait Formation adjacent to the Brunei border in Northeastern Sarawak has several oil wells and shows tremendous spatial variability that needs to be taken into account in reservoir characterization. Several sedimentation facies types were identified in the field. Several samples were selected from SK333 block for this study.The results indicate that heat transfer in clastics appears to be proportional to carbon contents and percentage of argillaceous material in the system. There appears to be an inverse relationship between the presence of Fe-oxyhydroxides in the matrix and heat transfer capabilities. In the non-clastics, certain facies such as the gray micritic facies appear to have high heat transfer capabilities. The transfer capability reduces from the carbonaceous to ferruginous varieties. Complex heterogeneity in fabric as seen in the fossiliferous varieties tends to lower the thermal conductivity to values as low as 3 Wm-1K-1. Normally specimens are selected to represent the cored geological sections from which they come. However, as the results of this study show that microvariability in fabrics is a dominant feature in these rocks, it is evident that utilizing such samples as representative samples for the overall geological formation couldresult in erroneous interpretations

    Single-Particle Spectroscopy on Large SAPO-34 Crystals at Work: Methanol-To-Olefin versus Ethanol-To-Olefin Processes

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    The formation of hydrocarbon pool (HCP) species during methanol- to-olefin (MTO) and ethanol-toolefin (ETO) processes have been studied on individual micron-sized SAPO- 34 crystals with a combination of in situ UV/Vis, confocal fluorescence, and synchrotron-based IR microspectroscopic techniques. With in situ UV/Vis microspectroscopy, the intensity changes of the l=400 nm absorption band, ascribed to polyalkylated benzene (PAB) carbocations, have been monitored and fitted with a first-order kinetics at low reaction temperatures. The calculated activation energy (Ea) for MTO, approximately 98 kJmol 1, shows a strong correlation with the theoretical values for the methylation of aromatics. This provides evidence that methylation reactions are the rate-determining steps for the formation of PAB. In contrast for ETO, the Ea value is approximately 60 kJmol 1, which is comparable to the Ea values for the condensation of light olefins into aromatics. Confocal fluorescence microscopy demonstrates that during MTO the formation of the initial HCP species are concentrated in the outer rim of the SAPO-34 crystal when the reaction temperature is at 600 K or lower, whereas larger HCP species are gradually formed inwards the crystal at higher temperatures. In the case of ETO, the observed egg-white distribution of HCP at 509 K suggests that the ETO process is kinetically controlled, whereas the square-shaped HCP distribution at 650 K is indicative of a diffusion- controlled process. Finally, synchrotron- based IR microspectroscopy revealed a higher degree of alkylation for aromatics for MTO as compared to ETO, whereas high reaction temperatures favor dealkylation processes for both the MTO and ETO processes

    Single-Particle Spectroscopy on Large SAPO-34 Crystals at Work: Methanol-to-Olefin versus Ethanol-to-Olefin Processes

    No full text
    The formation of hydrocarbon pool (HCP) species during methanol-to-olefin (MTO) and ethanol-to-olefin (ETO) processes have been studied on individual micron-sized SAPO-34 crystals with a combination of in situ UV/Vis, confocal fluorescence, and synchrotron-based IR microspectroscopic techniques. With in situ UV/Vis microspectroscopy, the intensity changes of the λ=400 nm absorption band, ascribed to polyalkylated benzene (PAB) carbocations, have been monitored and fitted with a first-order kinetics at low reaction temperatures. The calculated activation energy (Ea) for MTO, approximately 98 kJ mol−1, shows a strong correlation with the theoretical values for the methylation of aromatics. This provides evidence that methylation reactions are the rate-determining steps for the formation of PAB. In contrast for ETO, the Ea value is approximately 60 kJ mol−1, which is comparable to the Eavalues for the condensation of light olefins into aromatics. Confocal fluorescence microscopy demonstrates that during MTO the formation of the initial HCP species are concentrated in the outer rim of the SAPO-34 crystal when the reaction temperature is at 600 K or lower, whereas larger HCP species are gradually formed inwards the crystal at higher temperatures. In the case of ETO, the observed egg-white distribution of HCP at 509 K suggests that the ETO process is kinetically controlled, whereas the square-shaped HCP distribution at 650 K is indicative of a diffusion-controlled process. Finally, synchrotron-based IR microspectroscopy revealed a higher degree of alkylation for aromatics for MTO as compared to ETO, whereas high reaction temperatures favor dealkylation processes for both the MTO and ETO processes

    Evaluation criteria for construction waste management tools: Towards a holistic BIM framework

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    © 2016 Informa UK Limited, trading as Taylor & Francis Group. This study identifies evaluation criteria with the goal of appraising the performance of existing construction waste management tools and employing the results in the development of a holistic building information modelling (BIM) framework for construction waste management. Based on the literature, this paper identifies 32 construction waste management tools in five categories: (a) waste management plan templates and guides, (b) waste data collection and audit tools (c) waste quantification models, (d) waste prediction tools, and (e) geographic information system (GIS)-enabled waste tools. After reviewing these tools and conducting four focus-group interviews (FGIs), the findings revealed six categories of evaluation criteria (a) waste prediction; (b) waste data; (c) commercial and procurement; (d) BIM; (e) design; and (f) technological. The performance of the tools is assessed using the evaluation criteria and the result reveals that the existing tools are not robust enough to tackle construction waste management at the design stage. The paper therefore discusses the development of a holistic BIM framework with six layers: application; service domain; BIM business domain; presentation; data; and infrastructure. The BIM framework provides a holistic approach and organizes relevant knowledge required to tackle construction waste effectively at the design stage using an architecture-based layered approach. This framework will be of interest to software developers and BIM practitioners who seek to extend the functionalities of existing BIM software for construction waste management

    Global Asthma Network survey suggests more national asthma strategies could reduce burden of asthma

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    Background Several countries or regions within countries have an effective national asthma strategy resulting in a reduction of the large burden of asthma to individuals and society. There has been no systematic appraisal of the extent of national asthma strategies in the world. Methods The Global Asthma Network (GAN) undertook an email survey of 276 Principal Investigators of GAN centres in 120 countries, in 2013–2014. One of the questions was: “Has a national asthma strategy been developed in your country for the next five years? For children? For adults?”. Results Investigators in 112 (93.3%) countries answered this question. Of these, 26 (23.2%) reported having a national asthma strategy for children and 24 (21.4%) for adults; 22 (19.6%) countries had a strategy for both children and adults; 28 (25%) had a strategy for at least one age group. In countries with a high prevalence of current wheeze, strategies were significantly more common than in low prevalence countries (11/13 (85%) and 7/31 (22.6%) respectively, p < 0.001). Interpretation In 25% countries a national asthma strategy was reported. A large reduction in the global burden of asthma could be potentially achieved if more countries had an effective asthma strategy. © 2017 SEICA
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