Adsorption of dicamba and MCPA onto MIL-53(Al) metal–organic framework: response surface methodology and artificial neural network model studies

An aluminium-based metal–organic framework ((MOF), MIL-53(Al)), was hydrothermally synthesized, characterized and applied for the remediation of the herbicides dicamba (3,6-dichloro-2-methoxy benzoic acid) and 4-chloro-2-methylphenoxyacetic acid (MCPA) in aqueous medium. Response surface methodology (RSM) and artificial neural network (ANN) were used to design, optimize and predict the non-linear relationships between the independent and dependent variables. The shared interaction of the effects of key response parameters on the adsorption capacity were assessed using the central composite design-RSM and ANN optimization models. The optimum adsorption capacities for dicamba and MCPA are 228.5 and 231.9 mg g⁻¹, respectively. The RSM ANOVA results showed significant p-values, with coefficients of determination (R²) = 0.988 and 0.987 and R² adjusted = 0.974 and 0.976 for dicamba and MCPA, respectively. The ANN prediction model gave R² = 0.999 and 0.999, R² adjusted = 0.997 and 0.995 and root mean square errors (RMSEs) of 0.001 and 0.004 for dicamba and MCPA, respectively. In each set of experimental conditions used for the study, the ANN gave better prediction than the RSM, with high accuracy and minimal error. The rapid removal (∼25 min), reusability (5 times) and good agreement between the experimental findings and simulation results suggest the great potential of MIL-53(Al) for the remediation of dicamba and MCPA from water matrices.

Rapid equilibration within a short time, high adsorption capacity, optimization, multivariate interaction of adsorption parameters and artificial neural network prediction model.     

Using community-based research to shape the design and delivery of maternal health services in Northern Nigeria

Maternal mortality ratios in northern Nigeria are among the worst in the world, over 1,000 per 100,000 live births in 2008, with a very low level and quality of maternity services. In 2009, we carried out a study of the reasons for low utilisation of antenatal and delivery care among women with recent pregnancies, and the socio-cultural beliefs and practices that influenced them. The study included a quantitative survey of 6,882 married women, 119 interviews and 95 focus group discussions with community and local government leaders, traditional birth attendants, women who had attended maternity services and health care providers. Only 26% of the women surveyed had received any antenatal care and only 13% delivered in a facility with a skilled birth attendant for their most recent pregnancy. However, those who had had at least one antenatal consultation were 7.6 times more likely to deliver with a skilled birth attendant. Most pregnant women had little or no contact with the health care system for reasons of custom, lack of perceived need, distance, lack of transport, lack of permission, cost and/or unwillingness to see a male doctor. Based on these findings, we designed and implemented an integrated package of interventions that included upgrading antenatal, delivery and emergency obstetric care; providing training, supervision and support for new midwives in primary health centres and hospitals; and providing information to the community about safe pregnancy and delivery and the use of these services.     

Incidence of chronic atrophic gastritis: systematic review and meta-analysis of follow-up studies

Chronic atrophic gastritis (CAG) is an important precursor lesion of intestinal gastric cancer. As it is typically asymptomatic, epidemiological data on the incidence of CAG are sparse. We aimed to provide an overview of published data on CAG incidence (overall and according to risk factors) from follow-up studies. Articles with information on incidence of CAG published in English until 26th of July 2009 were identified through a systematic MEDLINE and EMBASE search. Data extracted include study characteristics and key findings regarding the incidence of CAG. A meta-analysis was performed on the association between Helicobacter pylori infection and CAG incidence. Overall, data on CAG incidence were available from 14 studies, in 7 studies incidence could be estimated according to H. pylori infection. Most studies were conducted in symptomatic or high risk populations and the maximum number of incident cases was 284. Incidence estimates ranged from 0 to 11% per year and were consistently below 1% in patients not infected with H. pylori. The highest incidence was observed in a special study conducted on ulcer patients treated by proximal gastric vagotomy. Rate ratios for the association between H. pylori infection and CAG incidence ranged from 2.4 to 7.6 with a summary estimate of 5.0 (95% confidence interval: 3.1–8.3). Incidence of CAG is very low in the absence of H. pylori infection. There is a need for more population-based studies to provide comparable estimates of incidence and the impact of risk factors in the development of CAG.