Viscoelastic gels of guar and xanthan gum mixtures provide long-term stabilization of iron micro- and nanoparticles

Iron micro- and nanoparticles used for groundwater remediation and medical applications are prone to fast aggregation and sedimentation. Diluted single biopolymer water solutions of guar gum (GG) or xanthan gum (XG) can stabilize these particles for few hours providing steric repulsion and by increasing the viscosity of the suspension. The goal of the study is to demonstrate that amending GG solutions with small amounts of XG (XG/GG weight ratio 1:19; 3 g/L of total biopolymer concentration) can significantly improve the capability of the biopolymer to stabilize highly concentrated iron micro- and nanoparticle suspensions. The synergistic effect between GG and XG generates a viscoelastic gel that can maintain 20 g/L iron particles suspended for over 24 h. This is attributed to (i) an increase in the static viscosity, (ii) a combined polymer structure the yield stress of which contrasts the downward stress exerted by the iron particles, and (iii) the adsorption of the polymers to the iron surface having an anchoring effect on the particles. The XG/GG viscoelastic gel is characterized by a marked shear thinning behavior. This property, coupled with the low biopolymer concentration, determines small viscosity values at high shear rates, facilitating the injection in porous media. Furthermore, the thermosensitivity of the soft elastic polymeric network promotes higher stability and longer storage times at low temperatures and rapid decrease of viscosity at higher temperatures. This feature can be exploited in order to improve the flowability and the delivery of the suspensions to the target as well as to effectively tune and control the release of the iron particle

Rationale, design and study protocol of the ‘Strong Families Start at Home’ feasibility trial to improve the diet quality of low-income, ethnically diverse children by helping parents improve their feeding and food preparation practices

There is an urgent need to create effective interventions that help parents establish a healthy diet among their children early in life, especially among low-income and ethnically and racially diverse families. U.S. children eat too few fruits, vegetables and whole grains, and too many energy dense foods, dietary behaviors associated with increased morbidity from chronic diseases. Parents play a key role in shaping children\u27s diets. Best practices suggest that parents should involve children in food preparation, and offer, encourage and model eating a variety of healthy foods. In addition, while parents help to shape food preferences, not all children respond in the same way. Certain child appetitive traits, such as satiety responsiveness (sensitivity to internal satiety signals), food responsiveness (sensitivity to external food cues), and food fussiness may help explain some of these differences. Prior interventions to improve the diet of preschool children have not used a holistic approach that targets the home food environment, by focusing on food quality, food preparation, and positive feeding practices while also acknowledging a child\u27s appetitive traits. This manuscript describes the rationale and design for a 6-month pilot randomized controlled trial, Strong Families Start at Home, that randomizes parents and their 2-to 5-year old children to either a home-based environmental dietary intervention or an attention-control group. The primary aim of the study is to explore the feasibility and acceptability of the intervention and evaluation and to determine the intervention\u27s preliminary efficacy on child diet quality, feeding practices, and availability of healthy foods in the home

Micronutrient Adequacy in Preschool Children Attending Family Child Care Homes

Limited data is available on the micronutrient intake and adequacy in preschool children enrolled in family child care homes (FCCH). The goal of this paper is to describe the micronutrient adequacy relative to age-specific recommendations of preschool-aged children (aged 2–5 years) attending FCCH in Rhode Island (RI). Dietary data among younger preschoolers (aged 2–3 years), n = 245) and older preschoolers (aged 4–5 years), n = 121) in 118 RI FCCH (N = 366 children) were analyzed. Nutrient adequacy was assessed as the amount of nutrient per 1000 kcal of the diet that would meet the Institute of Medicine nutrient requirements (critical nutrient density), and it was compared to the observed nutrient densities of the children. The sodium:potassium ratio was also calculated. For most micronutrients, the observed density met or exceeded the recommendation, meaning the children’s intake was adequate. However, a high proportion of children had nutrient densities under the recommendation for vitamins D, E, K, and potassium (86.1%, 89.1%, 70.8%, and 99.2% of children, respectively). The mean vitamin B12, potassium, and zinc densities were statistically higher in younger vs. older preschoolers (p \u3c 0.05 for all). Low densities in calcium and vitamins K and B5 were more frequent in older children vs. younger children (p \u3c 0.05). In addition, older preschoolers had a higher sodium:potassium ratio than younger children (p \u3c 0.05). The micronutrient intake density was adequate for most nutrients. However, intake of some nutrients was of concern. Further attention to training and compliance in FCCH may improve the diet quality of those cared for in these settings