Development of automated systems for the analysis of inorganic chloramines and trihalomethanes in water

La désinfection de l’eau par le chlore est largement répandue dans le monde afin de limiter les risques d’infections. Cependant, le chlore peut réagir avec des composés organiques et inorganiques présents dans les eaux en formant des sous-produits de désinfection potentiellement toxiques pour la santé humaine. Parmi ceux-ci, les chloramines inorganiques et les trihalométhanes sont les composés majeurs formés dans les eaux, et leur quantification pose un défi majeur.Dans cette étude, deux systèmes d’analyse en flux ont été développés afin de faciliter la portabilité de ces systèmes et de minimiser le coût du développement. Le premier système vise à analyser les chloramines inorganiques dans les eaux, et repose sur l’utilisation d’un module de chromatographie multi-seringue (MSC), permettant la séparation des chloramines inorganiques, suivie d’une réaction de dérivation post colonne qui améliore la sensibilité de la quantification des chloramines inorganiques. Le deuxième système permet d’analyser les trihalométhanes, le protocole d’analyse automatisée repose sur une version améliorée et optimisée de la réaction de Fujiwara et une étape de préconcentration sur phase solide.Ces deux systèmes permettent ainsi de quantifier ces deux familles de sous-produits de désinfection d’une manière sensible, fiable, sélective et peu coûteuse en utilisant l’analyse en flux.Chlorination of water is widely used to reduce the risk of waterborne infections. However, chlorine can react with organic and inorganic species present in water leading to the formation of disinfection-by-products known to pose human health problems because of their toxicities, especially inorganic chloramines and trihalomethanes. Furthermore, the quantification of these compounds poses a major analytical challenge because, as far as we know, there is no sensitive method that can differentiate between inorganic chloramines, and there is no portable and inexpensive method for the analysis of trihalomethanes.Two flow analytical-based systems have been developed in this study to facilitate their portability and to minimize the cost of development. The first system aims to analyze inorganic chloramines in water, it is based on the use of a Multi-syringe chromatography (MSC) module, allowing inorganic chloramines separation, followed by a post-column derivatization step with a chromophoric reagent that enhances the sensitivity and the selectivity of detection. The second system has been developed for the analysis of trihalomethanes in water, it is based on the optimized Fujiwara’s reaction and on a solid phase preconcentration step.These two systems developed allows quantification of these two families of disinfection by-products in a sensitive, reliable, selective and cheap way by using flow analysis

Placing a Lens on the First 1000 Days of Life: Prenatal Intake, Infant Feeding, the Microbiome and Child Growth

The first 1000 days of life, from conception until the child’s second birthday, constitute a critical window for child growth and development. During infancy and early childhood, significant and rapid physical changes occur, including increases in weight, height, and brain size and organ development accompanied by cognitive and psychomotor development. Adequate infant feeding, including breastfeeding and complementary feeding, that meets the infants’ energy and nutrient requirements can help protect against growth faltering, infant and child morbidity and mortality, and delayed mental and motor development. Adequate nutrition during this critical period can also protect against adverse health outcomes and chronic diseases later in life according to the hypothesis of developmental origins of health and disease. A web of factors that are country- and culture- specific influence infant feeding practices and child growth. Further, the microbiome has been suggested as a strong potential player in the association between infant nutrition and child growth. Therefore, the overarching theme of the current dissertation is to investigate hypotheses that can provide evidence to inform the paradigm linking socio-demographic, maternal, and child determinants including prenatal intake to infant feeding, the breast milk and infant gut microbiome, and child growth within the first 1000 days of life. Specifically, aims one and two examine the socio-demographic, maternal, and child determinants of child growth and breastfeeding in a cross-sectional survey of mother-child dyads in Lebanon, a middle-income country undergoing nutrition transition in the Middle East. The third aim focuses on the CHILD cohort study, a multi-center longitudinal prospective birth cohort study, to examine the associations between prenatal diet and supplement intake and the breast milk microbiome. Finally, the fourth aim is to review the evidence for the potential of the infant gut microbiome as a promising target linking complementary feeding to child undernutrition in low- and middleincome countries (LMIC) with the highest burden of undernutrition. The results for aim one revealed sex-specific determinants of child growth in Lebanon. The determinants examined through a hierarchical conceptual framework included: maternal and paternal education among boys and crowding index among girls at the distal sociodemographic level, and maternal obesity among girls at the intermediate maternal level. The proximal child determinants included birth length, number of children in the household and breastfeeding duration among girls, birthweight among boys and child’s age among boys and girls. In the analysis for aim two, breastfeeding practices were suboptimal in Lebanon as less than half (41.5%) of the infants were exclusively breastfed during the 40-day rest period and 12.3% were exclusively breastfed during the 6-month duration recommended by the World Health Organization. Higher socioeconomic status, as reflected by a larger number of cars owned, and Csection delivery were consistently inversely associated with lower odds of exclusive breastfeeding for 40 days and 6 months. Belonging to a family with more children was associated with higher odds of exclusive breastfeeding for 40 days; while maternal overweight and obesity were associated with lower odds of exclusive breastfeeding for 6 months

A scoping review of reporting ‘Ethical Research Practices’ in research conducted among refugees and war-affected populations in the Arab world

Abstract Background Ethical research conduct is a cornerstone of research practice particularly when research participants include vulnerable populations. This study mapped the extent of reporting ethical research practices in studies conducted among refugees and war-affected populations in the Arab World, and assessed variations by time, country of study, and study characteristics. Methods An electronic search of eight databases resulted in 5668 unique records published between 2000 and 2013. Scoping review yielded 164 eligible articles for analyses. Results Ethical research practices, including obtaining institutional approval, access to the community/research site, and informed consent/assent from the research participants, were reported in 48.2, 54.9, and 53.7% of the publications, respectively. Institutional approval was significantly more likely to be reported when the research was biomedical in nature compared to public health and social (91.7% vs. 54.4 and 32.4%), when the study employed quantitative compared to qualitative or mixed methodologies (61.7% vs. 26.8 and 42.9%), and when the journal required a statement on ethical declarations (57.4% vs. 27.1%). Institutional approval was least likely to be reported in papers that were sole-authored (9.5%), when these did not mention a funding source (29.6%), or when published in national journals (0%). Similar results were obtained for access to the community site and for seeking informed consent/assent from study participants. Conclusions The responsibility of inadequacies in adherence to ethical research conduct in crisis settings is born by a multitude of stakeholders including funding agencies, institutional research boards, researchers and international relief organizations involved in research, as well as journal editors, all of whom need to play a more proactive role for enhancing the practice of ethical research conduct in conflict settings

Development of an automated system for the analysis of inorganic chloramines in swimming pools via multi-syringe chromatography and photometric detection with ABTS

International audienceInorganic chloramines are disinfection by-products resulting from the unwanted reaction between chlorine used as disinfectant in swimming pools and nitrogenous compounds brought by bathers. This parameter (total chloramines or combined chlorine) is currently measured on site by a colorimetric method that does not allow to measure only inorganic chloramines. In this paper, a multi-syringe chromatography system combined with a post column derivatization is applied for the first time for the specific detection of the three individual inorganic chloramines (monochloramine, dichloramine and trichloramine). These latter ones are separated using a low-pressure monolithic C18 column, and separately detected after a post-column reaction with the chromogenic reagent ABTS (2,2'-azino-bis-(3-ethyl-benzothiazoline)-6-sulfonic acid-diammonium salt). Development of two ABTS reagents provides discrimination of chlorine and monochloramine that are not separated on the column. Optimization of the experimental conditions enables determination of inorganic chloramines with very good detection limits (around 10 µg eq.Cl2 L-1) without interferences from other chlorinated compounds such as organic chloramines or free available chlorine. The validation of the whole procedure has been successfully applied to real swimming pools samples

Additional file 1: of A scoping review of reporting ‘Ethical Research Practices’ in research conducted among refugees and war-affected populations in the Arab world

Inclusion and exclusion criteria. (DOCX 14 kb

In utero metabolomic signatures of refined grain intake and risk of gestational diabetes: A metabolome-wide association study.

BACKGROUND: Epidemiologic evidence has linked refined grain intake to a higher risk of gestational diabetes (GDM), but the biological underpinnings remain unclear. OBJECTIVES: We aimed to identify and validate refined grain-related metabolomic biomarkers for GDM risk. METHODS: In a metabolome-wide association study of 91 cases with GDM and 180 matched controls without GDM (discovery set) nested in the prospective Pregnancy Environment and Lifestyle Study (PETALS), refined grain intake during preconception and early pregnancy and serum untargeted metabolomics were assessed at gestational weeks 10-13. We identified refined grain-related metabolites using multivariable linear regression and examined their prospective associations with GDM risk using conditional logistic regression. We further examined the predictivity of refined grain-related metabolites selected by least absolute shrinkage and selection operator regression in the discovery set and validation set (a random PETALS subsample of 38 individuals with and 336 without GDM). RESULTS: Among 821 annotated serum (87.4% fasting) metabolites, 42 were associated with refined grain intake, of which 17 (70.6% in glycerolipids, glycerophospholipids, and sphingolipids clusters) were associated with subsequent GDM risk (all false discovery rate-adjusted P values <0.05). Adding 7 of 17 metabolites to a conventional risk factor-based prediction model increased the C-statistic for GDM risk in the discovery set from 0.71 (95% CI: 0.64, 0.77) to 0.77 (95% CI: 0.71, 0.83) and in the validation set from 0.77 (95% CI: 0.69, 0.86) to 0.81 (95% CI: 0.74, 0.89), both with P-for-difference <0.05. CONCLUSIONS: Clusters of glycerolipids, glycerophospholipids, and sphingolipids may be implicated in the association between refined grain intake and GDM risk, as demonstrated by the significant associations of these metabolites with both refined grains and GDM risk and the incremental predictive value of these metabolites for GDM risk beyond the conventional risk factors. These findings provide evidence on the potential biological underpinnings linking refined grain intake to the risk of GDM and help identify novel disease-related dietary biomarkers to inform diet-related preventive strategies for GDM

Prioritizing Variables for Observational Study Design using the Joint Variable Importance Plot

Observational studies of treatment effects require adjustment for confounding variables. However, causal inference methods typically cannot deliver perfect adjustment on all measured baseline variables, and there is often ambiguity about which variables should be prioritized. Standard prioritization methods based on treatment imbalance alone neglect variables’ relationships with the outcome. We propose the joint variable importance plot to guide variable prioritization for observational studies. Since not all variables are equally relevant to the outcome, the plot adds outcome associations to quantify the potential confounding jointly with the standardized mean difference. To enhance comparisons on the plot between variables with different confounding relationships, we also derive and plot bias curves. Variable prioritization using the plot can produce recommended values for tuning parameters in many existing matching and weighting methods. We showcase the use of the joint variable importance plots in the design of a balance-constrained matched study to evaluate whether taking an antidiabetic medication, glyburide, increases the incidence of C-section delivery among pregnant individuals with gestational diabetes.</p