Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000–17 : analysis for the Global Burden of Disease Study 2017

Background Across low-income and middle-income countries (LMICs), one in ten deaths in children younger than 5 years is attributable to diarrhoea. The substantial between-country variation in both diarrhoea incidence and mortality is attributable to interventions that protect children, prevent infection, and treat disease. Identifying subnational regions with the highest burden and mapping associated risk factors can aid in reducing preventable childhood diarrhoea. Methods We used Bayesian model-based geostatistics and a geolocated dataset comprising 15 072 746 children younger than 5 years from 466 surveys in 94 LMICs, in combination with findings of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, to estimate posterior distributions of diarrhoea prevalence, incidence, and mortality from 2000 to 2017. From these data, we estimated the burden of diarrhoea at varying subnational levels (termed units) by spatially aggregating draws, and we investigated the drivers of subnational patterns by creating aggregated risk factor estimates. Findings The greatest declines in diarrhoeal mortality were seen in south and southeast Asia and South America, where 54·0% (95% uncertainty interval [UI] 38·1–65·8), 17·4% (7·7–28·4), and 59·5% (34·2–86·9) of units, respectively, recorded decreases in deaths from diarrhoea greater than 10%. Although children in much of Africa remain at high risk of death due to diarrhoea, regions with the most deaths were outside Africa, with the highest mortality units located in Pakistan. Indonesia showed the greatest within-country geographical inequality; some regions had mortality rates nearly four times the average country rate. Reductions in mortality were correlated to improvements in water, sanitation, and hygiene (WASH) or reductions in child growth failure (CGF). Similarly, most high-risk areas had poor WASH, high CGF, or low oral rehydration therapy coverage. Interpretation By co-analysing geospatial trends in diarrhoeal burden and its key risk factors, we could assess candidate drivers of subnational death reduction. Further, by doing a counterfactual analysis of the remaining disease burden using key risk factors, we identified potential intervention strategies for vulnerable populations. In view of the demands for limited resources in LMICs, accurately quantifying the burden of diarrhoea and its drivers is important for precision public health

Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4 (62.3 (55.1�70.8) million) to 6.4 (58.3 (47.6�70.7) million), but is predicted to remain above the World Health Organization�s Global Nutrition Target of <5 in over half of LMICs by 2025. Prevalence of overweight increased from 5.2 (30 (22.8�38.5) million) in 2000 to 6.0 (55.5 (44.8�67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic. © 2020, The Author(s)

Global Retinoblastoma Presentation and Analysis by National Income Level

Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4) were female. Most patients (n = 3685 84.7%) were from low-and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 62.8%), followed by strabismus (n = 429 10.2%) and proptosis (n = 309 7.4%). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 95% CI, 12.94-24.80, and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 95% CI, 4.30-7.68). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs. © 2020 American Medical Association. All rights reserved

Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)

An amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)

Author Correction: Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017 (Nature Medicine, (2020), 26, 5, (750-759), 10.1038/s41591-020-0807-6)

An amendment to this paper has been published and can be accessed via a link at the top of the paper. © 2020, The Author(s)

Determination of optimum conditions and the kinetics of methanol oxidation

In this study, the catalytic oxidation of methanol to formaldehyde was investigated in a laboratory-scale fixedbed catalytic reactor, under a large number of different conditions. Iron-molybdate catalysts supported by silica or alumina with a molybdenium/iron (Mo/Fe) ratio of 1.5, 3 and 5 were studied for the gas phase reaction. In order to obtain the optimum conditions, six different temperatures in the range of 250-375°C and three different space times of 50.63, 33.75 and 20.25 g/(mol/h) were investigated. After determining the optimum conditions for this reaction, experiments aimed at understanding the reaction kinetics, were carried out. These experiments were performed on the catalyst favoring the formation of formaldehyde, which has a (Mo/Fe) ratio of 5 on a silica support. Seven reaction models derived by the mechanisms cited in the literature were tested to elucidate the kinetics of the reaction and the surface reaction controlling model was found to be the most suitable reaction mechanism. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Catalytic hydrogenation of crotonaldehyde in trickle-bed reactor

The liquid-phase hydrogenation of crotonaldehyde to n-butyraldehyde, was investigated. A palladium based commercial catalyst (w = 0.05 % Pd on Al 2O3) was used in a laboratory scale trickle-bed reactor. The influence of temperature on the reaction, crotonaldehyde and hydrogen flow rates satisfying trickle flow conditions, and the appropriate space velocity LHSV and space time ranges, were searched. The operating conditions were proposed as the temperature range of 30 - 50°C, the LHSV space velocity range of 2-7 h-1, and the space time (mw/FCAo) range of 250 - 4108 g min mol-1, at constant hydrogen/crotonaldehyde molar ratio as 2:1, at atmospheric pressure. Kinetic experiments were performed to calculate the reaction rates and then to explore the rate expression in trickle-bed reactor. The data between space time and conversion were evaluated at the different studied temperatures and the relation between these parameters was derived by regression. The reaction rates were calculated by differentiation of the derived equations. The reaction rate expression was derived by using "Power Law" model. Kinetic parameters were calculated by taking into consideration external and internal mass transfer resistances

Determination of adsorption and kinetic parameters for transesterification of methyl acetate with hexanol catalyzed by ion exchange resin

The transesterification of methyl acetate and 1-hexanol catalyzed by the cation exchange resin Amberlyst-131 was studied to obtain optimum operating parameters, adsorption parameters, and kinetic parameters. The effects of temperature, molar ratio of ester to alcohol, stirrer speed, and catalyst loading on the reaction rate were investigated. The chemical equilibrium constants were obtained from kinetic experiments and theoretically from standard thermodynamic properties at temperatures of 333, 338, 343, and 348 K. The experimental data were tested with the pseudohomogeneous and adsorption based models. The activity coefficients were estimated using UNIQUAC to account for the nonideal thermodynamic behavior of reactants and products for both models. The activation energy for the transesterification reaction was found to be 37.8 kJ mol -1 by the Langmuir-Hinshelwood-Haugen-Watson (LHHW) model, which correlates the experimental data. © 2012 American Chemical Society

Esterification of acrylic acid with different alcohols catalyzed by zirconia supported tungstophosphoric acid

The liquid phase esterification of acrylic acid with different alcohols (butanol, iso-butanol, or hexanol) was investigated in a batch reactor with zirconia supported tungstophosphoric acid (TPA) as heterogeneous catalyst. The prepared catalysts with different TPA loadings (20, 25, and 30 wt %) and calcination temperatures (550, 650, and 750 °C) were characterized by nitrogen adsorption studies, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques. In addition, acidity measurements were performed by potentiometric titration with n-butylamine. The activitiy of catalysts strongly dependent on the acidic characteristic of the catalysts. The most active catalyst, 25 wt % TPA, calcined at 650 °C, gave more than 33%, 31%, and 27% conversions of acrylic acid for butyl, iso-butyl, and hexyl acrylate synthesis, respectively. © 2012 American Chemical Society