Effects of feed composition on the fouling on cation-exchange membranes desalinating polymer-flooding produced water.

HYPOTHESIS: Cation exchange membranes (CEMs) are subject to fouling when utilized to desalinate wastewater from the oil and gas industry, hampering their performance. The kind and extent of the fouling are most likely dependent on the composition of the stream, which in practical applications can vary significantly. EXPERIMENTS: Fouling experiments were performed on commercial cation exchange membranes, which were used in electrodialysis runs to desalinate solutions of varying composition. The variations included ionic strength, type of ions, amount of viscosifying polyelectrolyte (partially hydrolyzed polyacrylamide), presence of crude oil, and surfactants. Performance parameters, like electric potential and pH, were monitored during the runs, after which the membranes were recovered and analyzed. FINDINGS: Fouling was detected on most CEMs and occurred mainly in the presence of the viscosifying polyelectrolyte. Under normal pH conditions (pH ~ 8), the polyelectrolyte fouled the concentrate side of the CEMs, as expected due to electrophoresis. However, by applying a current in the opposite direction, the polyelectrolyte layer could be removed. Precipitation occurred mostly on the opposite side of the membrane, with different morphology depending on the feed composition.

Influence of solution composition on fouling of anion exchange membranes desalinating polymer-flooding produced water.

HYPOTHESIS: Anion exchange membranes (AEMS) are particularly prone to fouling when employed to desalinate polymer flooding produced water (PFPW), an abundant sub-product from the oil and gas industry. The formation of fouling on an AEM will be affected by the composition of the solution, which includes various dissolved salts, partially hydrolyzed polyacrylamide (HPAM), crude oil, and surfactants. EXPERIMENTS: Electrodialysis experiments were performed to desalinate feed solutions with different compositions, aiming to distinguish between their individual and combined effects. The solutions contained diverse mono- and divalent ions. The analysis included data collected during the desalination and characterization of the fouled AEMs by diverse analytical techniques. FINDINGS: HPAM produced the most severe effects in terms of visible fouling and increase of resistance. This polyelectrolyte fouls the AEM by adsorbing on its surface and by forming a viscous gel layer that hampers the replenishment of ions from the bulk solution. Ca and Mg have a large influence on the formation of thick HPAM gel layers, while the oily compounds have only a minimal influence acting mainly as a destabilizing agent. The membranes also presented scaling consisting of calcium precipitates. The effects of the gel layer were minimized by applying current reversal and foulant-free solution.

GROW: a model for mentorship to advance women's leadership in global health.

In this essay, we discuss the under-representation of women in leadership positions in global health (GH) and the importance of mentorship to advance women's standing in the field. We then describe the mentorship model of GROW, Global Research for Women. We describe the theoretical origins of the model and an adapted theory of change explaining how the GROW model for mentorship advances women's careers in GH. We present testimonials from a range of mentees who participated in a pilot of the GROW model since 2015. These mentees describe the capability-enhancing benefits of their mentorship experience with GROW. Thus, preliminary findings suggest that the GROW mentorship model is a promising strategy to build women's leadership in GH. We discuss supplemental strategies under consideration and next steps to assess the impact of GROW, providing the evidence to inform best practices for curricula elsewhere to build women's leadership in GH.

Signs of emotional disturbance three years after early hospitalization.

Tested by a retrospective study the hypothesis that children in the 6-36 months age range in case of lengthy (> 3 days) or repeated (more than once) hospitalization are susceptible to persistent emotional disturbances. Families of children with such a "risky" hospitalization history were approached by mail, several years (M = 36 months, SD = 10) after the latest discharge. The parents of these children (N = 40; mean age 59 months) and of a control group without a risky hospitalization history (N = 73; mean age 58 months) reported about current problem behavior of their child. Scores on the Behaviour Checklist (Richman et al., 1982) were significantly (p < .05) elevated in the sample. Specific signs were poor concentration, immoderate attention seeking, deficits of bowel control, and fearfulness. Cases of surgery significantly exceeded others in signs of disturbance. Although the protective value of parental attendance could not be demonstrated in this study, on the basis of prior research, rooming-in is recommended as a necessary precaution in the 6-36 months age range.

Early intervention for children with developmental disabilities: manifesto of the Eurlyaid working party.

Eurlyaid is a working party of the European Community (EC). It consists of experts and representatives of parents' associations from the various member states involved in early intervention for children who are disabled or at risk of developmental disabilities. Starting from the growing recognition of the importance of early identification and intervention Eurlyaid aims to contribute to the development of a common EC policy and legislation. Here we describe a comprehensive framework for early intervention, presented as a preliminary manifesto. First of all the Manifesto gives a definition of key concepts, delineates the target group and states the rationale behind, and the content, of early intervention. Secondly, we present the conditions and demands necessary to attain the best quality early intervention, and make a number of recommendations. With an EC grant, Eurlyaid is able to continue its activities as part of ALEFPA-Europe, a so-called non-governmental organization (NGO).

Energy cost of lactation, and energy balances of well-nourished Dutch lactating women: reappraisal of the extra energy requirements of lactation.

At 9 wk postpartum the difference in energy intake of 40 lactating (2440 +/- 430 kcal/d) and 16 nonlactating women (1680 +/- 400 kcal/d) was 760 kcal/d but decreased to 550 kcal/d when adjusted for habitual intakes and body weight. Energy cost of lactation amounted to 650 kcal/d (breast-milk production, 745 +/- 130 g/d). When compared with nonlactating counterparts, the lactating women mainly achieved energy balance by eating more. Sixteen of the 40 lactating women were also studied at 56 wk. Their cost of lactation at 5-13 wk was 630 kcal/d (breast-milk production, 720 +/- 124 g/d); these women met their energy cost of lactation by eating more (415 kcal/d); by tissue mobilization (35 kcal/d), and by reducing energy expenditure (180 kcal/d). The present study helps in the understanding of how well-nourished women with an adequate lactational performance may cope in everyday life with the energy stress of lactation, and suggests that current recommendations of energy needs during lactation are too high.

Energy cost of physical activity throughout pregnancy and the first year postpartum in Dutch women with sedentary lifestyles.

Basal metabolic rate (BMR), activity pattern, and energy costs of some daily activities were measured in 25 Dutch women throughout pregnancy and the first year postpartum. Physical activity index (PAI), which refers to daily energy expenditure expressed as a multiple of BMR, was calculated from activity-pattern data and activity costs. Mean PAIs (+/- SD) throughout pregnancy, during the first 6 mo postpartum, and at 1 y postpartum were 1.48 +/- 0.08, 1.49 +/- 0.07, and 1.53 +/- 0.10 X BMR, respectively. Because measured BMR at 1 y postpartum was 1440 +/- 168 kcal/d, costs for physical activity in pregnancy and the first 6 mo postpartum were, respectively, approximately 70 and approximately 50 kcal/d lower than at 1 y postpartum. For women with sedentary lifestyles the energy saved during pregnancy and lactation because of decreased physical activity and decreased costs of activities will be limited.

Energy cost of walking at a fixed pace and self-paced before, during, and after pregnancy.

Body weight, basal metabolic rate (BMR), and treadmill metabolic rate (TMR) (3.9 km/h, no elevation) were measured in 39 women at 12, 24, and 36 wk gestation and at 9 wk postpartum. Prepregnancy measurements were also made on 15 of the women. TMR at 36 wk (3.65 +/- 0.50 kcal/min) was significantly higher than at 24 wk (3.38 +/- 0.43 kcal/min) or at 9 wk postpartum (3.38 +/- 0.43 kcal/min). Net energy cost (TMR minus BMR) at 36 wk gestation (2.42 +/- 0.40 kcal/min) was not different from prepregnancy or postpartum values but was significantly higher than at 12 wk (2.28 +/- 0.39 kcal/min) and 24 wk (2.28 +/- 0.37 kcal/min) gestation. In eight women the energy cost of self-paced walking on a treadmill was measured. The absolute and net energy cost decreased sharply from 6 to 12 wk gestation (by 8% and 11%, respectively) but remained unchanged afterwards. The data suggest that in the energy requirements for pregnant women no additional allowance need be made for physical activity, even if a woman's activity pattern includes a substantial amount of externally paced work.

Body fat mass and basal metabolic rate in Dutch women before, during, and after pregnancy: a reappraisal of energy cost of pregnancy.

Body weight, fat mass, and basal metabolic rate were measured longitudinally from early pregnancy until 2 mo postpartum in 57 healthy Dutch women; 23 of whom were also studied before pregnancy. Weight gain over pregnancy was 11.8 +/- 3.7 kg and weight gain from 12 wk gestation to delivery was 10.3 +/- 3.8 kg. Birth weights and placental weights were 3458 +/- 527 and 657 +/- 114 g, respectively. Gain in maternal fat stores over pregnancy was 2.0 +/- 2.6 kg and difference in fat mass from 12 wk gestation to 5 wk postpartum was 1.2 +/- 2.2 kg. The energy equivalent of the gain in fat stores, including costs of synthesizing, can be estimated as 22,000 kcal. The cumulative increment in basal metabolism over pregnancy was 34,350 +/- 30,000 kcal. When the energy equivalent of the gain in tissue other than fat stores is assumed to be approximately 11,750 kcal, total energy cost of pregnancy is at 68,100 +/- 38,560 kcal.

New equations for estimating body fat mass in pregnancy from body density or total body water.

The equations for estimating fat mass from body density or total body water are not appropriate for application in pregnancy, because the underlying assumptions with respect to density and composition of fat-free mass do not hold for pregnancy. Representative values have been derived from literature data for density and water content of maternal fat-free mass throughout pregnancy. Using these values we developed a method that provides new equations for estimating fat mass from body density or total body water for any desired stage of pregnancy. The validity of the new equations based on body density is discussed using data on body weight and body density obtained from a longitudinal study on well-nourished Dutch pregnant women. Because the new equations result in more valid estimates of maternal body fat mass, we suggest that they be used in studies on energy balance in pregnancy.

Energy requirements of pregnancy in The Netherlands.

57 healthy Dutch women were studied longitudinally from early pregnancy until 2 months post partum. Regular measurements were made of energy intake in food, basal metabolic rate, body weight and body fat mass, and levels of physical activity. Some data were obtained before conception in 23 women. The energy cost of pregnancy calculated as the energy deposited as new tissues plus the associated increase in basal metabolism amounted to 286 MJ (1020 kJ/day), which is only 11% lower than the theoretical estimate of requirements of 323 MJ (1 MJ = 239 kcal). Energy intake throughout the first 10 wk of pregnancy was identical to that before pregnancy. Energy intake was only 200 kJ/day higher in late than in early pregnancy (not significant), and the cumulative increase in energy intake over pregnancy was estimated as 22 MJ (about 80 kJ/day). There is, therefore, an energy gap in pregnancy of about 940 kJ/day. It is proposed that the main mechanisms by which the pregnant body is able to save energy and to bridge the energy gap are by adjustments to physical activity and an increase in work efficiency and an adaptation of the metabolic response to food. Savings on physical activity by behavioural adaptations will not exceed 355 kJ/day.

PIP: 57 study subjects, who live in or near the city of Wageningen, The Netherlands, participated in this study designed to determine energy requirements in pregnancy and lactation. The 57 Dutch women, studied longitudinally from early pregnancy until 2 months postpartum, were judged to be healthy by medical histories, blood pressure, blood hemoglobin, and urine analysis. 23 women also were studied prior to conception. The women were from middle-upper socioeconomic levels, worked as housewives, were not obese, and all were white. 53 women delivered at term (gestation 259-293 days), 2 before term (244 and 248 days), and 2 after term (294 and 297 days). Birthweights were judged normal for gestational age in all but 2 children. Food consumption was measured on 54 women at about 11, 23, and 35 weeks gestation. Food intake also was assessed before pregnancy in 20 women. In another subgroup of 31 women additional food consumption measurements were made at about 17 and 29 weeks gestation. Food intake was always assessed over 5 consecutive days by the individual-weighed inventory technique. Basal metabolic rate (BMR) was measured by open-circuit indirect calorimetry with Douglas bagas and calculated with Weir's equation. At each laboratory visit body weight was measured on a beam balance; body fat mass was assessed by the skinfold method and the densitometric method. A subgroup of 18 women kept detailed physical activity diaries for 5 consecutive days simultaneously with the dietary surveys. The body weight at 10 weeks gestation was 1.1 kg higher than before pregnancy (n=23). Throughout the remainder of pregnancy, body weight increased by 10.5 kg (n=57). At about 10 weeks gestation body fat mass was 0.4 kg (not significant) higher than before pregnancy (n=19). In the last 10 weeks of pregnancy body fat mass was 2.1 kg (significant) above the value at 10 weeks (n=42). Body weight and body fat mass remained unchanged from 1-2 months postpartum. The energy cost of pregnancy calculated as the energy deposited as new tissues added to the associated increase in basal metabolism amounted to 286 MJ (1020 kJ/day). This is only 11% lower than the theoretical estimate of requirements of 323 MJ (1 MJ=239 kcal). Throughout the first 10 weeks of pregnancy, energy intake was the same as that before pregnancy. Energy intake was 200 kJ/day higher in late than in early pregnancy (not significant); the cumulative increase in energy intake over pregnancy was estimated to be 22 MJ (about 80 kJ/da). There is an energy gap in pregnancy of about 940 kU/day. Physiological and metabolic adaptions will bring about a lowering of energy expenditure in pregnancy by a reduction in dietary-induced thermogenesis and/or an increase in work efficiency.