Influence of Aqueous Phase Salt and Oil Phase Surfactants and Viscosity on the Dynamic Interfacial Tension and Coalescence Timescales.

Liquid-liquid separation is a critically important process in the treatment of emulsions that can occur in our environment, such as oily stormwater, shipboard bilgewater, or off-shore oil spill treatment. Effective filtration systems, including coalescing filters, are essential for mitigating these environmental pollutants. Achieving this requires a comprehensive understanding of liquid-liquid interface dynamics influenced by additives and surfactants. Furthermore, understanding the impact of surfactants on emulsion stability in saline environments is vital for optimizing filtration processes and ensuring the protection of marine and freshwater ecosystems. In this work, these effects are highlighted using measurements performed across a range of droplet size, surfactant concentration, viscosity ratios, and saline presence. Dynamic IFT measurements are conducted using the pendant drop method for water in light mineral oil, with and without salt in the water phase. The effect of salt addition is also highlighted by using microfluidic coalescence experiments, in which it was found that the addition of salt increases the dimensionless drainage time below the critical micelle concentration. The second focus of this work is to study the effect of bulk phase viscosity on the stability. Dynamic IFT measurements are performed at both millimeter and micrometer scales using pendant drop experiments and microfluidic tensiometry, respectively, involving light and heavy mineral oils with varying SPAN80 surfactant concentrations. The surfactant diffusivity and interfacial adsorption and desorption rates are then extracted by fitting a surfactant diffusion and equation of state equations to the dynamic IFT measurements. The results of the IFT decay, surfactant diffusivity, and adsorption rates are compared at two different viscosity ratios. This study also compares the times required for IFT relaxation with the film drainage times in water-in-oil systems. The comparison aids in comprehending the impact of competing timescales during film drainage. The findings presented in this paper offer valuable insights into the design and optimization of liquid-liquid filtration systems, especially when operating under challenging environmental conditions, such as in saline environments. The principles explored here can be applied to improving industrial water treatment and in the design of advanced filtration technologies for chemical and petrochemical industries, particularly those involving flow, contributing to more sustainable and efficient practices in handling emulsified waste streams.

Bonding and Infants' Development and Quality of Life: A Study Among Mothers with Severe Mental Illnesses in Remission.

Background: Maternal mental health has specific implications for bonding and infants' mental health. However, most of the evidence comes from mothers who are either symptomatic or did not have adequate mental health support. In this context, our objective was to explore if symptom status in mothers and bonding share any significant association with the infants' development and quality of life (QOL), in case of mothers with severe mental illnesses in remission. Methods: The study included 41 mother-infant dyads from the outpatient perinatal psychiatry services and the mother-baby unit of the current study center. Symptom status, self-reported bonding, mother-infant interactions, and infants' development and QOL were assessed with Clinical Global Impressions, Postpartum Bonding Questionnaire, Pediatric Infant-Parent Exam, Developmental Assessment Scales for Indian Infants, and Pediatric Quality of Life Scale, respectively. Results: Most mothers had a complete recovery or minimal symptoms. Nine (22%) infants had a significant developmental delay. Atypical play-based interactions were observed in nine (22%) mothers. Self-reported bonding and bonding as evinced over play-based interactions did not significantly correlate with the QOL or development of the infants. Mothers who have recovered and are functioning well reported good bonding with their infants, though objective assessment revealed specific difficulties. Symptom severity correlated with poor physical QOL in infants. Conclusion: The association between mothers' bonding and infants' mental health is domain-specific and differential than linear and robust. Infants of mothers with severe mental illnesses postpartum should be routinely monitored for mother-infant bonding, development, and quality of life.

Just Transition for Healthy People on a Healthy Planet.

The definition of Just Transition in recent years has been shaped by the political and ideological leanings of multiple stakeholders. Labor movements look at a Just Transition that secures workers' rights and jobs; environmental justice groups include whole communities impacted by fossil fuel in their description; multilateral institutions, investors, and transnational corporations see it through lenses of economics, financial support, and investment. However, a perspective on health is missing in all these approaches. The COVID-19 pandemic has established the importance of health-based planning, making evident the co-dependence of ecological health and human well-being. The debilitating post-pandemic economic crisis has reiterated the interlinkage between economics, public health, and the environment. This document posits that health is the overlapping but missing link between the different movements' dream for Just Transition into an equitable world, and to heal people and the planet damaged by fossil fuels. We need Just Transition that has holistic health systems and accessible healthcare services at its core.

Altered cerebellar lobular volumes correlate with clinical deficits in siblings and children with ASD: evidence from toddlers.

BACKGROUND: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by impaired social and communication skills, narrow interests, and repetitive behavior. It is known that the cerebellum plays a vital role in controlling movement and gait posture. However, recently, researchers have reported that the cerebellum may also be responsible for other functions, such as social cognition, reward, anxiety, language, and executive functions. METHODS: In this study, we ascertained volumetric differences from cerebellar lobular analysis from children with ASD, ASD siblings, and typically developing healthy controls. In this cross-sectional study, a total of 30 children were recruited, including children with ASD (N = 15; mean age = 27.67 ± 5.1 months), ASD siblings (N = 6; mean age = 17.5 ± 3.79 months), and typically developing children (N = 9; mean age = 17.67 ± 3.21 months). All the MRI data was acquired under natural sleep without using any sedative medication. We performed a correlation analysis with volumetric data and developmental and behavioral measures obtained from these children. Two-way ANOVA and Pearson correlation was performed for statistical data analysis. RESULTS: We observed intriguing findings from this study, including significantly increased gray matter lobular volumes in multiple cerebellar regions including; vermis, left and right lobule I-V, right CrusII, and right VIIb and VIIIb, respectively, in children with ASD, compared to typically developing healthy controls and ASD siblings. Multiple cerebellar lobular volumes were also significantly correlated with social quotient, cognition, language, and motor scores with children with ASD, ASD siblings, and healthy controls, respectively. CONCLUSIONS: This research finding helps us understand the neurobiology of ASD and ASD-siblings, and critically advances current knowledge about the cerebellar role in ASD. However, results need to be replicated for a larger cohort from longitudinal research study in future.

A systematic review and meta-analysis of early childhood intervention programs for developmental difficulties in low-and-middle-income countries.

Early acknowledgment of developmental difficulties in young children strengthens both preventive and therapeutic approaches. Despite their feasibility, early intervention services are limited in Low-and-Middle-Income (LAMI) countries compared to high income countries. The aim of this study was to examine the evidence for early childhood intervention programs for developmental difficulties in children below five years in LAMI countries through a systematic review and meta-analysis. In this background, original studies published in peer-reviewed journals from 2010 to 2019 with a focus on developmental difficulties including delays and deviances; randomized research design with a clear description of the intervention and measurable outcomes, and conducted in LAMI countries were considered for the systematic review. Electronic databases, including ProQuest, PubMed, Ovid, EBSCOhost, and Google Scholar, were searched using a combination of specific keywords. PRISMA guidelines were followed to include the studies. Each of the selected study was assessed for quality before applying appropriate statistics to synthesize the data. Fourteen publications were identified from 2697 publications for the systematic review, out of which four were found compatible for a meta-analysis. The studies reviewed were conducted in Bangladesh, India, Pakistan, Uganda, Vietnam, and Zambia. A meta-analysis of four studies provided considerable evidence for the effects of early developmental intervention. This systematic review provides an evidence for early childhood intervention programs in LAMI countries. Implications of these findings for the early childhood programs are discussed in this article.

Dilatational rheology of water-in-diesel fuel interfaces: effect of surfactant concentration and bulk-to-interface exchange.

Micrometer-sized water droplets dispersed in diesel fuel are stabilized by the fuel's surface-active additives, such as mono-olein and poly(isobutylene)succinimide (PIBSI), making the droplets challenging for coalescing filters to separate. Dynamic material properties found from interfacial rheology are known to influence the behavior of microscale droplets in coalescing filters. In this work, we study the interfacial dilatational properties of water-in-fuel interfaces laden with mono-olein and PIBSI, with a fuel phase of clay-treated ultra-low sulphur diesel (CT ULSD). First, the dynamic interfacial tension (IFT) is measured using pendant drop tensiometry, and a curvature-dependent form of the Ward and Tordai diffusion equation is applied for extracting the diffusivity of the surfactants. Additionally, Langmuir kinetics are applied to the dynamic IFT results to obtain the maximum surface concentration (Γ∞) and ratio of adsorption to desorption rate constants (κ). We then use a capillary pressure microtensiometer to measure the interfacial dilatational modulus, and further extract the characteristic frequency of surfactant exchange (ω0) by fitting a model assuming diffusive exchange between the interface and bulk. In this measurement, 50-100 µm diameter water droplets are pinned at the tip of a glass capillary in contact with the surfactant-containing fuel phase, and small amplitude capillary pressure oscillations over a range of frequencies from 0.45-20 rad s-1 are applied to the interface, inducing changes in interfacial tension and area to yield the dilatational modulus, E*(ω). Over the range of concentrations studied, the dilatational modulus of CT ULSD with either mono-olein or PIBSI increases with a decrease in bulk concentration and plateaus at the lowest concentrations of mono-olein. Characteristic frequency (ω0) values extracted from the fit are compared with those calculated using equilibrium surfactant parameters (κ and Γ∞) derived from pendant drop tensiometry, and good agreement is found between these values. Importantly, the results imply that diffusive exchange models based on the equilibrium relationships between surfactant concentration and interfacial tension can be used to infer the dynamic dilatational behavior of complex surfactant systems, such as the water-in-diesel fuel interfaces in this study.

Phase-Dependent Surfactant Transport on the Microscale: Interfacial Tension and Droplet Coalescence.

Liquid-liquid emulsion systems are usually stabilized by additives, known as surfactants, which can be observed in various environments and applications such as oily bilgewater, water-entrained diesel fuel, oil production, food processing, cosmetics, and pharmaceuticals. One important factor that stabilizes emulsions is the lowered interfacial tension (IFT) between the fluid phases due to surfactants, inhibiting the coalescence. Many studies have investigated the surfactant transport behavior that leads to corresponding time-dependent lowering of the IFT. For example, the rate of IFT decay depends on the phase in which the surfactant is added (dispersed vs continuous) due in part to differences in the near-surface depletion depth. Other key factors, such as the viscosity ratio between the dispersed and continuous phases and Marangoni stress, will also have an impact on surfactant transport and therefore the coalescence and emulsion stability. In this feature article, the measurement techniques for dynamic IFT are first reviewed due to their importance in characterizing surfactant transport, with a specific focus on macroscale versus microscale techniques. Next, equilibrium isotherm models as well as dynamic diffusion and kinetic equations are discussed to characterize the surfactant and the time scale of the surfactant transport. Furthermore, recent studies are highlighted showing the different IFT decay rates and its long-time equilibrium value depending on the phase into which the surfactant is added, particularly on the microscale. Finally, recent experiments using a hydrodynamic Stokes trap to investigate the impact of interfacial surfactant transport, or "mobility", and the phase containing the surfactant on film drainage and droplet coalescence will be presented.

Insights into the Microscale Coalescence Behavior of Surfactant-Stabilized Droplets Using a Microfluidic Hydrodynamic Trap.

Coalescence of micrometer-scale droplets is impacted by several parameters, including droplet size, viscosities of the two phases, droplet velocity, angle of approach, as well as interfacial tension and surfactant coverage. The thinning dynamics of films between coalescing droplets can be particularly complex in the presence of surfactants, due to the generation of Marangoni stresses and reduced film mobility. Here, a microfluidic hydrodynamic "Stokes" trap is used to gently steer and trap surfactant-laden micrometer-sized droplets at the center of a cross-slot. Water droplets are formed upstream of the cross-slot using a microfluidic T-junction, in heavy and light mineral oils and stabilized using SPAN 80, an oil-soluble surfactant. Incoming droplets are made to coalesce with the trapped droplet, yielding measurements of the film drainage time. Film drainage times are measured as a function of continuous phase viscosity, incoming droplet speed, trapped droplet size, and surfactant concentrations above and below the critical micelle concentration (CMC). As expected, systems with higher surfactant concentrations and slower incoming droplet speed exhibit longer film drainage times. At low surfactant concentrations, the drainage time is longer for the more viscous heavy mineral oil in the continuous phase, whereas at high surfactant concentrations, the dependence on continuous phase viscosity vanishes. Perhaps more surprisingly, larger droplets and high confinement also result in longer film drainage times, potentially due to deformation of the droplet interfaces. The results are used here to determine critical conditions for coalescence, including both an upper and a lower critical capillary number. Moreover, it is shown that induced surfactant concentration gradient effects enable coalescence events after the droplets had originally flocculated, at surfactant concentrations above the CMC. The microfluidic hydrodynamic trap provides new insights into the role of surfactants in film drainage and opens avenues for controlled coalescence studies at micrometer length scales and millisecond time scales.

Increasing Isoprene Epoxydiol-to-Inorganic Sulfate Aerosol Ratio Results in Extensive Conversion of Inorganic Sulfate to Organosulfur Forms: Implications for Aerosol Physicochemical Properties.

Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), key isoprene oxidation products, with inorganic sulfate aerosol yields substantial amounts of secondary organic aerosol (SOA) through the formation of organosulfur compounds. The extent and implications of inorganic-to-organic sulfate conversion, however, are unknown. In this article, we demonstrate that extensive consumption of inorganic sulfate occurs, which increases with the IEPOX-to-inorganic sulfate concentration ratio (IEPOX/Sulfinorg), as determined by laboratory measurements. Characterization of the total sulfur aerosol observed at Look Rock, Tennessee, from 2007 to 2016 shows that organosulfur mass fractions will likely continue to increase with ongoing declines in anthropogenic Sulfinorg, consistent with our laboratory findings. We further demonstrate that organosulfur compounds greatly modify critical aerosol properties, such as acidity, morphology, viscosity, and phase state. These new mechanistic insights demonstrate that changes in SO2 emissions, especially in isoprene-dominated environments, will significantly alter biogenic SOA physicochemical properties. Consequently, IEPOX/Sulfinorg will play an important role in understanding the historical climate and determining future impacts of biogenic SOA on the global climate and air quality.

Body part representations in verbal semantics.

Embodied theories of language propose that word meaning is inextricably tied to-grounded in-mental representations of perceptual, motor, and affective experiences of the world. The four experiments described in this article demonstrate that accessing the meanings of action verbs like smile, punch, and kick requires language understanders to activate modality-specific cognitive representations responsible for performing and perceiving those same actions. The main task used is a word-image matching task, where participants see an action verb and an image depicting an action. Their task is to decide as quickly as possible whether the verb and the image depict the same action. Of critical interest is participants' behavior when the verb and image do not match, in which case the two actions can use the same effector or different effectors. In Experiment 1, we found that participants took significantly longer to reject a verb-image pair when the actions depicted by the image and denoted by the verb used the same effector than when they used different effectors. Experiment 2 yielded the same result when the order of presentation was reversed, replicating the effect in Cantonese. Experiment 3 replicated the effect in English with a verb-verb near-synonym task, and in Experiment 4, we once again replicated the effect with learners of English as a second language. This robust interference effect, whereby a shared effector slows discrimination, shows that language understanders activate effector-specific neurocognitive representations during both picture perception and action word understanding.