324 research outputs found

    FPGA technology in process tomography

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    The aims of this paper are to provide a review of the process tomography applications employing field programmable gate arrays (FPGA) and to understand current FPGA related researches, in order to seek for the possibility to applied FPGA technology in an ultrasonic process tomography system. FPGA allows users to implement complete systems on a programmable chip, meanwhile, five main benefits of applying the FPGA technology are performance, time to market, cost, reliability, and long-term maintenance. These advantages definitely could help in the revolution of process tomography, especially for ultrasonic process tomography and electrical process tomography. Future work is focused on the ultrasonic process tomography for chemical process column investigation using FPGA for the aspects of low cost, high speed and reconstructed image quality

    Preparation and characterization of chromium metal organic framework for carbon dioxide adsorption

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    Greenhouse gases (GHGs) have greatly changed the global climate in the recent year. Metal organic frameworks (MOFs) is one of the solutions which can be utilized as gas adsorbents to capture carbon dioxide (CO2), the main contributor of greenhouse effect. MOF possesses good CO2 adsorption ability attributed to its high surface area to volume ratio and pore size. Nevertheless, the success of the MOF is greatly depend on the fabrication parameter such as fabrication methods, type of metal oxide, type of organic linkers used and the molar ratio of the reactant. In this study, chromium (VI) oxide, trimesic acid and terephthalic acid were used to fabricate MOFs by solvothermal method to investigate the performance of CO2 adsorption. The characterization tests by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) shows that Cr-TMA-1:5 amongst the rest of the fabricated MOF possess the shape of small irregular diagonal with highest surface area to volume ratio which was ideal in CO2 adsorption. Furthers, the result CO2 adsorption test carried by thermogravimetric analyser (TGA) suggested the MOF Cr-TMA-1:5 possesses the highest the CO2 adsorption capacity recorded at 0.099 mmol/g. This had revealed that MOFs composed of chromium (VI) oxide and trimesic acid possess the potential to be applied in CO2 adsorption

    Preparation, characterization, and performance evaluation of polysulfone hollow fiber membrane with PEBAX or PDMS coating for oxygen enhancement process

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    Air pollution is a widely discussed topic amongst the academic and industrial spheres as it can bring adverse effects to human health and economic loss. As humans spend most of their time at the office and at home, good indoor air quality with enriched oxygen concentration is particularly important. In this study, polysulfone (PSF) hollow fiber membranes fabricated by dry-jet wet phase inversion method were coated by a layer of polydimethylsiloxane (PDMS) or poly(ether block amide) (PEBAX) at different concentrations and used to evaluate their performance in gas separation for oxygen enrichment. The surface-coated membranes were characterized using SEM and EDX to determine the coating layer thickness and surface chemical properties, respectively. Results from the gas permeation study revealed that the PSF membrane coated with PDMS offered higher permeance and selectivity compared to the membrane coated with PEBAX. The best performing PDMS-coated membrane demonstrated oxygen and nitrogen gas permeance of 18.31 and 4.01 GPU, respectively with oxygen/nitrogen selectivity of 4.56. Meanwhile, the PEBAX-coated membrane only showed 12.23 and 3.11 GPU for oxygen and nitrogen gas, respectively with a selectivity of 3.94. It can be concluded the PDMS coating is more promising for PSF hollow fiber membrane compared to the PEBAX coating for the oxygen enrichment process

    The usefulness of rapid diagnostic tests in the new context of low malaria transmission in zanzibar.

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    BACKGROUND\ud \ud We assessed if histidine-rich-protein-2 (HRP2) based rapid diagnostic test (RDT) remains an efficient tool for Plasmodium falciparum case detection among fever patients in Zanzibar and if primary health care workers continue to adhere to RDT results in the new epidemiological context of low malaria transmission. Further, we evaluated the performance of RDT within the newly adopted integrated management of childhood illness (IMCI) algorithm in Zanzibar.\ud \ud METHODS AND FINDINGS\ud \ud We enrolled 3890 patients aged ≄2 months with uncomplicated febrile illness in this health facility based observational study conducted in 12 primary health care facilities in Zanzibar, between May-July 2010. One patient had an inconclusive RDT result. Overall 121/3889 (3.1%) patients were RDT positive. The highest RDT positivity rate, 32/528 (6.1%), was found in children aged 5-14 years. RDT sensitivity and specificity against PCR was 76.5% (95% CI 69.0-83.9%) and 99.9% (95% CI 99.7-100%), and against blood smear microscopy 78.6% (95% CI 70.8-85.1%) and 99.7% (95% CI 99.6-99.9%), respectively. All RDT positive, but only 3/3768 RDT negative patients received anti-malarial treatment. Adherence to RDT results was thus 3887/3889 (99.9%). RDT performed well in the IMCI algorithm with equally high adherence among children <5 years as compared with other age groups.\ud \ud CONCLUSIONS\ud \ud The sensitivity of HRP-2 based RDT in the hands of health care workers compared with both PCR and microscopy for P. falciparum case detection was relatively low, whereas adherence to test results with anti-malarial treatment was excellent. Moreover, the results provide evidence that RDT can be reliably integrated in IMCI as a tool for improved childhood fever management. However, the relatively low RDT sensitivity highlights the need for improved quality control of RDT use in primary health care facilities, but also for more sensitive point-of-care malaria diagnostic tools in the new epidemiological context of low malaria transmission in Zanzibar.\ud \ud TRIAL REGISTRATION\ud \ud ClinicalTrials.gov NCT01002066

    CD-loop Extension in Zika Virus Envelope Protein Key for Stability and Pathogenesis

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    With severe disease manifestations including microcephaly, congenital malformation, and Guillain-BarrĂ© syndrome, Zika virus (ZIKV) remains a persistent global public health threat. Despite antigenic similarities with dengue viruses, structural studies have suggested the extended CD-loop and hydrogen-bonding interaction network within the ZIKV envelope protein contribute to stability differences between the viral families. This enhanced stability may lead to the augmented infection, disease manifestation, and persistence in body fluids seen following ZIKV infection. To examine the role of these motifs in infection, we generated a series of ZIKV recombinant viruses that disrupted the hydrogen-bonding network (350A, 351A, and 350A/351A) or the CD-loop extension (Δ346). Our results demonstrate a key role for the ZIKV extended CD-loop in cell-type-dependent replication, virion stability, and in vivo pathogenesis. Importantly, the Δ346 mutant maintains similar antigenicity to wild-type virus, opening the possibility for its use as a live-attenuated vaccine platform for ZIKV and other clinically relevant flaviviruses

    “Even if You Know Everything You Can Forget”: Health Worker Perceptions of Mobile Phone Text-Messaging to Improve Malaria Case-Management in Kenya

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    This paper presents the results of a qualitative study to investigate the perceptions and experiences of health workers involved in a a cluster-randomized controlled trial of a novel intervention to improve health worker malaria case-management in 107 government health facilities in Kenya. The intervention involved sending text-messages about paediatric outpatient malaria case-management accompanied by “motivating” quotes to health workers’ mobile phones. Ten malaria messages were developed reflecting recommendations from the Kenyan national guidelines. Two messages were delivered per day for 5 working days and the process was repeated for 26 weeks (May to October 2009). The accompanying quotes were unique to each message. The intervention was delivered to 119 health workers and there were significant improvements in correct artemether-lumefantrine (AL) management both immediately after the intervention (November 2009) and 6 months later (May 2010). In-depth interviews with 24 health workers were undertaken to investigate the possible drivers of this change. The results suggest high acceptance of all components of the intervention, with the active delivery of information in an on the job setting, the ready availability of new and stored text messages and the perception of being kept ‘up to date’ as important factors influencing practice. Applying the construct of stages of change we infer that in this intervention the SMS messages were operating primarily at the action and maintenance stages of behaviour change achieving their effect by creating an enabling environment and providing a prompt to action for the implementation of case management practices that had already been accepted as the clinical norm by the health workers. Future trials testing the effectiveness of SMS reminders in creating an enabling environment for the establishment of new norms in clinical practice as well as in providing a prompt to action for the implementation of the new case-management guidelines are justified

    Poor nutritional status of schoolchildren in urban and peri-urban areas of Ouagadougou (Burkina Faso)

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    <p>Abstract</p> <p>Background</p> <p>Malnutrition is still highly prevalent in developing countries. Schoolchildren may also be at high nutritional risk, not only under-five children. However, their nutritional status is poorly documented, particularly in urban areas. The paucity of information hinders the development of relevant nutrition programs for schoolchildren. The aim of this study carried out in Ouagadougou was to assess the nutritional status of schoolchildren attending public and private schools.</p> <p>Methods</p> <p>The study was carried out to provide baseline data for the implementation and evaluation of the Nutrition Friendly School Initiative of WHO. Six intervention schools and six matched control schools were selected and a sample of 649 schoolchildren (48% boys) aged 7-14 years old from 8 public and 4 private schools were studied. Anthropometric and haemoglobin measurements, along with thyroid palpation, were performed. Serum retinol was measured in a random sub-sample of children (N = 173). WHO criteria were used to assess nutritional status. Chi square and independent t-test were used for proportions and mean comparisons between groups.</p> <p>Results</p> <p>Mean age of the children (48% boys) was 11.5 ± 1.2 years. Micronutrient malnutrition was highly prevalent, with 38.7% low serum retinol and 40.4% anaemia. The prevalence of stunting was 8.8% and that of thinness, 13.7%. The prevalence of anaemia (p = 0.001) and vitamin A deficiency (p < 0.001) was significantly higher in public than private schools. Goitre was not detected. Overweight/obesity was low (2.3%) and affected significantly more children in private schools (p = 0.009) and younger children (7-9 y) (p < 0.05). Thinness and stunting were significantly higher in peri-urban compared to urban schools (p < 0.05 and p = 0.004 respectively). Almost 15% of the children presented at least two nutritional deficiencies.</p> <p>Conclusion</p> <p>This study shows that malnutrition and micronutrient deficiencies are also widely prevalent in schoolchildren in cities, and it underlines the need for nutrition interventions to target them.</p

    Oleate but not stearate induces the regulatory phenotype of myeloid suppressor cells

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    Tumor infiltrating myeloid cells play contradictory roles in the tumor development. Dendritic cells and classical activated macrophages support anti- tumor immune activity via antigen presentation and induction of pro- inflammatory immune responses. Myeloid suppressor cells (MSCs), for instance myeloid derived suppressor cells (MDSCs) or tumor associated macrophages play a critical role in tumor growth. Here, treatment with sodium oleate, an unsaturated fatty acid, induced a regulatory phenotype in the myeloid suppressor cell line MSC-2 and resulted in an increased suppression of activated T cells, paralleled by increased intracellular lipid droplets formation. Furthermore, sodium oleate potentiated nitric oxide (NO) production in MSC-2, thereby increasing their suppressive capacity. In primary polarized bone marrow cells, sodium oleate (C18:1) and linoleate (C18:2), but not stearate (C18:0) were identified as potent FFA to induce a regulatory phenotype. This effect was abrogated in MSC-2 as well as primary cells by specific inhibition of droplets formation while the inhibition of de novo FFA synthesis proved ineffective, suggesting a critical role for exogenous FFA in the functional induction of MSCs. Taken together our data introduce a new unsaturated fatty acid-dependent pathway shaping the functional phenotype of MSCs, facilitating the tumor escape from the immune system

    Validation of TOI-1221 b: A warm sub-Neptune exhibiting TTVs around a Sun-like star

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    We present a validation of the long-period (91.68278−0.00041+0.0003291.68278^{+0.00032}_{-0.00041} days) transiting sub-Neptune planet TOI-1221 b (TIC 349095149.01) around a Sun-like (mV_{\rm V}=10.5) star. This is one of the few known exoplanets with period >50 days, and belongs to the even smaller subset of which have bright enough hosts for detailed spectroscopic follow-up. We combine TESS light curves and ground-based time-series photometry from PEST (0.3~m) and LCOGT (1.0~m) to analyze the transit signals and rule out nearby stars as potential false positive sources. High-contrast imaging from SOAR and Gemini/Zorro rule out nearby stellar contaminants. Reconnaissance spectroscopy from CHIRON sets a planetary scale upper mass limit on the transiting object (1.1 and 3.5 MJup_{\rm Jup} at 1σ\sigma and 3σ\sigma, respectively) and shows no sign of a spectroscopic binary companion. We determine a planetary radius of Rp=2.91−0.12+0.13R⊕R_{\rm p} = 2.91^{+0.13}_{-0.12} R_{\oplus}, placing it in the sub-Neptune regime. With a stellar insolation of S=6.06−0.77+0.85 S⊕S = 6.06^{+0.85}_{-0.77}\ S_{\oplus}, we calculate a moderate equilibrium temperature of Teq=T_{\rm eq} = 440 K, assuming no albedo and perfect heat redistribution. We find a false positive probability from TRICERATOPS of FPP =0.0014±0.0003 = 0.0014 \pm 0.0003 as well as other qualitative and quantitative evidence to support the statistical validation of TOI-1221 b. We find significant evidence (>5σ5\sigma) of oscillatory transit timing variations, likely indicative of an additional non-transiting planet.Comment: 17 pages, 9 figures, 4 table
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