Responsiveness to Glucagon in Fetal Hearts SPECIES VARIABILITY AND APPARENT DISPARITIES BETWEEN CHANGES IN BEATING, ADENYLATE CYCLASE ACTIVATION, AND CYCLIC AMP CONCENTRATION

A B S T R A C T Previous studies of the ability of the immature heart to respond to glucagon have yielded conflicting results. To test the possibility that the apparent discrepancies might be explained in part by species variability, isolated hearts of fetal mice and rats (13-22 days' gestational age) were studied under identical conditions in vitro. Changes in atrial rate and ventricular contractility were measured in spontaneously beating hearts exposed to glucagon, and activation of adenylate cyclase was assayed in cardiac homogenates. In mice of 16 days' gestational age or less, there was no change in heart rate in response to glucagon; at 17-18 days, minimal responsiveness was present; and after 19 days, 10 AM glucagon caused an increase in spontaneous atrial rate of 30+4% (SEM) (P < 0.001). Measurement of the extent and speed of volume displacement of the isotonically contracting hearts with a specially constructed capacitance transducer revealed that ventricular inotropic responsiveness also appeared after 17-19 days. Cardiac stores of glycogen were reduced in older hearts exposed to glucagon, but not in those aged less than 16 days. In contrast, glucagon failed to activate adenylate cyclase in homogenates of hearts of fetal mice at any age. Furthermore, glucagon failed to elicit an increase in the concentration of cycli

Unpredictable maternal sensory signals in caregiving behavior are associated with child effortful control

Emerging evidence suggests that exposure to unpredictable patterns of maternal sensory signals during infancy is associated with child neurodevelopment, including poorer effortful control. However, longitudinal effects on child development and possible sex differences are understudied. The aims of the present study were to explore whether exposure to unpredictable maternal sensory signals during infancy is related to child effortful control at 5 years of age and whether child sex moderates these associations. In addition, we examined how exposure to very high vs. low/moderate unpredictability using categorical cut-offs is related to child effortful control. Participants (133 mother–child pairs, all Caucasian) were drawn from the FinnBrain Birth Cohort Study in Finland. Maternal sensory signals (auditory, visual, tactile) were coded from the 10-min free-play episode on a moment-on-moment basis using Observer XT 11 (Noldus), and the unpredictability of maternal sensory signals was characterized as the entropy rate when the infant was 8 months of age. Child effortful control was assessed via mother reports using the Child Behavior Questionnaire very short form (CBQ-VSF) when the child was 5 years old. Correlational analyses showed that higher unpredictability of maternal sensory signals had a modest association with children’s poorer effortful control at 5 years of age. Notably, the linear regression model showed that child sex moderated these associations, as higher exposure to unpredictable maternal sensory signals was related to poorer effortful control among males, but not among females. Moreover, the general linear model showed that exposure to very high unpredictability was associated with poorer child effortful control at 5 years of age and remained significant when adjusted for possible confounding factors. These results are in line with previous findings and suggest that the unpredictability of maternal sensory signals is potentially an important aspect of early caregiving behavior associated with the development of child effortful control.</p

Alkaline residues and the environment: A review of impacts, management practices and opportunities

Around two billion tonnes of alkaline residues are produced globally each year by industries such as steel production, alumina refining and coal-fired power generation, with a total production estimate of 90 billion tonnes since industrialization. These wastes are frequently stored in waste piles or landfills, and can be an environmental hazard if allowed to generate dust, or if rainwater infiltrates the waste. This review will focus on the environmental impacts associated with alkaline residues, with emphasis on the leachates produced by rainwater ingress. Many alkaline industrial wastes can produce leachates that are enriched with trace metals that form oxyanions (e.g. As, Cr, Mo, Se, V), which can be very mobile in alkaline water. The management options for the residues and their leachates are also discussed, distinguishing active and passive treatment options. Potential reuses of these materials, in construction materials, as agricultural amendments, and in environmental applications are identified. The mechanisms of carbon sequestration by alkaline residues are assessed, and the potential for enhancing its rate as a climate change off-setting measure for the industry is evaluated. The potential for recovery of metals critical to e-technologies, such as vanadium, cobalt, lithium and rare earths, from alkaline residues is considered. Finally research needs are identified, including the need to better understand the biogeochemistry of highly alkaline systems in order to develop predictable passive remediation and metal recovery technologies