80 research outputs found

    New mechanistic model to simulate microalgae growth

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    The prospect of treating wastewater and at the same time producing microalgae biomass is receiving increasing attention. Mechanistic models for microalgae growth in wastewater are currently being developed for new systems design as well as to improve the understanding of the involved biokinetic processes. However, mathematical models able to describe the complexity of microalgal cultures are still not a common practice. The aim of the present study is to present and calibrate a new mechanistic model built in COMSOL Multiphysics™ platform for the description of microalgae growth. Carbon-limited algal growth, transfer of gases to the atmosphere; and photorespiration, photosynthesis kinetics and photoinhibition are included. The model considers the growth of microalgae as a function of light intensity and temperature, as well as availability of nitrogen and other nutrients. The model was calibrated using experimental data from a case study based on the cultivation of microalgae species in synthetic culture medium. The model was able to reproduce experimental data. Simulation results show the potential of the model to predict microalgae growth and production, nutrient uptake, and the influence of temperature, light intensity and pH on biokinetic processes of microalgae.Peer ReviewedPostprint (author's final draft

    Public health impact of low-dose aspirin on colorectal cancer, cardiovascular disease and safety in the UK – Results from micro-simulation model

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    Background: Low-dose aspirin therapy reduces the risk of cardiovascular disease and may have a positive effect on the prevention of colorectal cancer. We evaluated the population-level expected effect of regular low-dose aspirin use on cardiovascular disease (CVD), colorectal cancer (CRC), gastrointestinal bleeding, symptomatic peptic ulcers, and intracranial hemorrhage, using a microsimulation study design. Methods: We used individual-level state transition modeling to assess the impact of aspirin in populations aged 50–59 or 60–69 years old indicated for low-dose aspirin usage for primary or secondary CVD prevention. Model parameters were based on data from governmental agencies from the UK or recent publications. Results: In the 50–59 years cohort, a decrease in incidence rates (IRs per 100 000 person years) of non-fatal CVD (-203 and -794) and fatal CVD (-97 and-381) was reported in the primary and secondary CVD prevention setting, respectively. The IR reduction of CRC (-96 and -93) was similar for primary and secondary CVD prevention. The IR increase of non-fatal (116 and 119) and fatal safety events (6 and 6) was similar for primary and secondary CVD prevention. Similar results were obtained for the 60–69 years cohort. Conclusions: The decrease in fatal CVD and CRC events was larger than the increase in fatal safety events and this difference was more pronounced when low-dose aspirin was used for secondary compared to primary CVD prevention. These results provide a comprehensive image of the expected effect of regular low-dose aspirin therapy in a UK population indicated to use aspirin for CVD prevention. © 202

    Impact of community-acquired paediatric rotavirus gastroenteritis on family life: data from the REVEAL study

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    <p>Abstract</p> <p>Background</p> <p>Rotavirus is the leading cause of acute gastroenteritis (AGE) and the most frequent cause of severe diarrhoea in children aged less than 5 years. Although the epidemiology of rotavirus gastroenteritis (RVGE) is well documented, there are few data on the impact of RVGE on the families of affected children.</p> <p>Methods</p> <p>Data associated with the burden of RVGE, including number of working days lost, levels of parental stress, the need for alternative childcare arrangements and additional nappies used, were extracted from questionnaires completed by parents of children participating in a prospective, multicentre, observational study (Rotavirus gastroenteritis Epidemiology and Viral types in Europe Accounting for Losses in public health and society, REVEAL), conducted during 2004-2005 in selected areas of Belgium, France, Germany, Italy, Spain, Sweden, and the United Kingdom to estimate the incidence of RVGE in children aged less than 5 years seeking medical care as a result of AGE.</p> <p>Results</p> <p>1102 children with RVGE were included in the present analysis. The proportion of RVGE cases that required at least one parent or other person to be absent from work was 39%-91% in the hospital setting, 44%-64% in the emergency department, and 20%-64% in primary care. Self-reported levels of parental stress were generally high (mean stress levels, ≥ 5 on a 10-point visual analogue scale). Additional childcare arrangements were required in up to 21% of RVGE episodes. The mean number of nappies used per day during RVGE episodes was approximately double that used when the child was not ill.</p> <p>Conclusions</p> <p>Paediatric RVGE cases cause disruption to families and parental stress. The burden of RVGE on children and their families could be substantially reduced by routine rotavirus vaccination of infants.</p

    Burden of paediatric Rotavirus Gastroenteritis (RVGE) and potential benefits of a universal Rotavirus vaccination programme with a pentavalent vaccine in Spain

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    <p>Abstract</p> <p>Background</p> <p>Rotavirus is the most common cause of gastroenteritis in young children worldwide. The aim of the study was to assess the health outcomes and the economic impact of a universal rotavirus vaccination programme with RotaTeq, the pentavalent rotavirus vaccine, versus no vaccination programme in Spain.</p> <p>Methods</p> <p>A birth cohort was followed up to the age of 5 using a cohort model. Epidemiological parameters were taken from the REVEAL study (a prospective epidemiological study conducted in Spain, 2004-2005) and from the literature. Direct and indirect costs were assessed from the national healthcare payer and societal perspectives by combining health care resource utilisation collected in REVEAL study and unit costs from official sources. RotaTeq per protocol efficacy data was taken from a large worldwide rotavirus clinical trial (70,000 children). Health outcomes included home care cases, General Practioner (GP)/Paediatrician, emergency department visits, hospitalisations and nosocomial infections.</p> <p>Results</p> <p>The model estimates that the introduction of a universal rotavirus vaccination programme with RotaTeq (90% coverage rate) would reduce the rotavirus gastroenteritis (RVGE) burden by 75% in Spain; 53,692 home care cases, 35,187 GP/Paediatrician visits, 34,287 emergency department visits, 10,987 hospitalisations and 2,053 nosocomial infections would be avoided. The introduction of RotaTeq would avoid about 76% of RVGE-related costs from both perspectives: €22 million from the national health system perspective and €38 million from the societal perspective.</p> <p>Conclusions</p> <p>A rotavirus vaccination programme with RotaTeq would reduce significantly the important medical and economic burden of RVGE in Spain.</p

    LCA of greywater management within a water circular economy restorative thinking framework

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    Greywater reuse is an attractive option for the sustainable management of water under water scarcity circumstances, within a water circular economy restorative thinking framework. Its successful deployment relies on the availability of low cost and environmentally friendly technologies. The life cycle assessment (LCA) approach provides the appropriate methodological tool for the evaluation of alternative treatments based on environmental decision criteria and, therefore, it is highly useful during the process conceptual design. This methodology should be employed in the early design phase to select those technologies with lower environmental impact. This work reports the comparative LCA of three scenarios for greywater reuse: photocatalysis, photovoltaic solar-driven photocatalysis and membrane biological reactor, in order to help the selection of the most environmentally friendly technology. The study has been focused on the removal of the surfactant sodium dodecylbenzenesulfonate, which is used in the formulation of detergents and personal care products and, thus, widely present in greywater. LCA was applied using the Environmental Sustainability Assessment methodology to obtain two main environmental indicators in order to simplify the decision making process: natural resources and environmental burdens. Energy consumption is the main contributor to both indicators owing to the high energy consumption of the light source for the photocatalytic greywater treatment. In order to reduce its environmental burdens, the most desirable scenario would be the use of solar light for the photocatalytic transformation. However, while the technological challenge of direct use of solar light is approached, the environmental suitability of the photovoltaic solar energy driven photocatalysis technology to greywater reuse has been demonstrated, as it involves the smallest environmental impact among the three studied alternatives.Financial support from the Spanish Ministry of Economy and Competitiveness and from FEDER funds for projects CTM2013-43539-R, CTM2015-69845-R and CTQ2015-66078-R(MINECO/FEDER, UE) is gratefully acknowledged. Sara Dominguez and Jara Laso would also like to express their gratitude for the FPI postgraduate research grants (BES-2013-064055 and BES-2014-069368)

    Epidemiology, Molecular Characterization and Antibiotic Resistance of Neisseria meningitidis from Patients ≤15 Years in Manhiça, Rural Mozambique

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    BACKGROUND: The epidemiology of meningococcal disease in Mozambique and other African countries located outside the "meningitis belt" remains widely unknown. With the event of upcoming vaccines microbiological and epidemiological information is urgently needed. METHODS: Prospective surveillance for invasive bacterial infections was conducted at the Manhiça District hospital (rural Mozambique) among hospitalized children below 15 years of age. Available Neisseria meningitidis isolates were serogrouped and characterized by Multilocus Sequence Typing (MLST). Antibiotic resistance was also determined. RESULTS: Between 1998 and 2008, sixty-three cases of confirmed meningococcal disease (36 meningitis, 26 sepsis and 1 conjunctivitis) were identified among hospitalized children. The average incidence rate of meningococcal disease was 11.6/100,000 (8/100,000 for meningitis and 3.7/100,000 for meningococcemia, respectively). There was a significant rise on the number of meningococcal disease cases in 2005-2006 that was sustained till the end of the surveillance period. Serogroup was determined for 43 of the 63 meningococcal disease cases: 38 serogroup W-135, 3 serogroup A and 2 serogroup Y. ST-11 was the most predominant sequence type and strongly associated with serogroup W-135. Two of the three serogroup A isolates were ST-1, and both serogroup Y isolates were ST-175. N. meningitidis remained highly susceptible to all antibiotics used for treatment in the country, although the presence of isolates presenting intermediate resistance to penicillin advocates for continued surveillance. CONCLUSIONS: Our data show a high rate of meningococcal disease in Manhiça, Mozambique, mainly caused by serogroup W-135 ST-11 strains, and advocates for the implementation of a vaccination strategy covering serogroup W-135 meningococci in the country

    Meltwater layer dynamics in a central Arctic lead: Effects of lead width, re-freezing, and mixing during late summer

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    17 pages, 9 figures, 1 table.-- Data accessibility statement: The data analyzed in this study were mainly retrieved from links below: RINKO profiler-derived variables: https://doi.pangaea.de/10.1594/PANGAEA.945337, water sampling derived variables: https://doi.pangaea.de/10.1594/PANGAEA.945285, meteorological variables: https://doi.org/10.1594/PANGAEA.935267, and MSS profiler-derived variables: https://doi.org/10.1594/PANGAEA.939816. The oxygen isotope data stems from the ISOLAB Facility at AWI in PotsdamLeads play an important role in the exchange of heat, gases, vapour, and particles between seawater and the atmosphere in ice-covered polar oceans. In summer, these processes can be modified significantly by the formation of a meltwater layer at the surface, yet we know little about the dynamics of meltwater layer formation and persistence. During the drift campaign of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC), we examined how variation in lead width, re-freezing, and mixing events affected the vertical structure of lead waters during late summer in the central Arctic. At the beginning of the 4-week survey period, a meltwater layer occupied the surface 0.8 m of the lead, and temperature and salinity showed strong vertical gradients. Stable oxygen isotopes indicate that the meltwater consisted mainly of sea ice meltwater rather than snow meltwater. During the first half of the survey period (before freezing), the meltwater layer thickness decreased rapidly as lead width increased and stretched the layer horizontally. During the latter half of the survey period (after freezing of the lead surface), stratification weakened and the meltwater layer became thinner before disappearing completely due to surface ice formation and mixing processes. Removal of meltwater during surface ice formation explained about 43% of the reduction in thickness of the meltwater layer. The remaining approximate 57% could be explained by mixing within the water column initiated by disturbance of the lower boundary of the meltwater layer through wind-induced ice floe drift. These results indicate that rapid, dynamic changes to lead water structure can have potentially significant effects on the exchange of physical and biogeochemical components throughout the atmosphere–lead–underlying seawater systemThis study was supported by the Japan Society for the Promotion of Science (grant numbers: JP18H03745; JP18KK0292; JP17KK0083; JP17H04715; JP20H04345) and by a grant from the Joint Research Program of the Japan Arctic Research NetworkCenter. MM and HM are supported through the German Federal Ministry of Education and Research (grant number 03FO869A). ALW and KS were funded through the UK Natural Environment Research Council (NERC) (Grants No NE/S002596/1 and NE/S002502/1, respectively). ESD was supported by NERC through the EnvEast Doctoral Training Partnership (NE/L002582/1), as well as NERC and the Department for Business, Energy & Industrial Strategy (BEIS) through the UK Arctic Office. EJC was supported by the National Science Foundation (USA) NSF OPP 1821911 and NSF Graduate Research Fellowship. CG was funded through the Spanish funding Agency (AEI) though the grant PCI 2019-111844-2. MMS was funded through NSF OPP-1724467, OPP-1724748, and OPP-2138787. DB was funded through the German funding Agency (DFG) through grant BA1689/4-1With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)Peer reviewe

    Clinical characteristics and complications of rotavirus gastroenteritis in children in east London: A retrospective case-control study.

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    BACKGROUND: Rotavirus is the leading cause of acute gastroenteritis in children and is associated with neurological complications such as seizures and encephalopathy. The aim of this study was to investigate the presentation and complications of rotavirus compared to non-rotavirus gastroenteritis in UK children. METHODS: This was a retrospective, case-control, hospital-based study conducted at three sites in east London, UK. Cases were children aged 1 month to 16 years diagnosed with acute gastroenteritis between 1 June 2011 and 31 December 2013, in whom stool virology investigations confirmed presence of rotavirus by PCR. They were matched by age, gender and month of presentation to controls with rotavirus-negative gastroenteritis. RESULTS: Data were collected from 116 children (50 cases and 66 controls). Children with rotavirus gastroenteritis tended to present more frequently with metabolic acidosis (pH 7.30 vs 7.37, P = 0.011) and fever (74% versus 46%; P = 0.005) and were more likely to require hospitalisation compared to children with non-rotavirus gastroenteritis (93% versus 73%; P = 0.019). Neurological complications were the most common extra-intestinal manifestations, but did not differ significantly between children with rotavirus-positive gastroenteritis (RPG) and rotavirus-negative gastroenteritis (RNG) (24% versus 15%, respectively; P = 0.24). Encephalopathy occurred only in children with rotavirus infection (n = 3, 6%). CONCLUSION: Rotavirus causes longer and more severe disease compared to other viral pathogens. Seizures and milder neurological signs were surprisingly common and associated with multiple pathogens, but encephalopathy occurred only in children with rotavirus gastroenteritis. Rotavirus vaccination may reduce seizures and presentation to hospital, but vaccines against other pathogens causing gastroenteritis are required.AJP receives funding from the Wellcome Trust (grant 108065/Z/15/Z)
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