Wrinkling in the deflation of elastic bubbles

The protein hydrophobin HFBII self-assembles into very elastic films at the surface of water; these films wrinkle readily upon compression. We demonstrate and study this wrinkling instability in the context of non-planar interfaces by forming HFBII layers at the surface of bubbles; the interfaces are then compressed by deflating the bubble. By varying the initial concentration of the hydrophobin solutions, we are able to show that buckling occurs at a critical packing fraction of protein molecules on the surface. Independent experiments show that at this packing fraction the interface has a finite positive surface tension, and not zero surface tension as is usually assumed at buckling. We attribute this non-zero wrinkling tension to the finite elasticity of these interfaces. We develop a simple geometrical model for the evolution of the wrinkle length with further deflation, and show that wrinkles start close to the needle used for deflation and grow rapidly towards the mid-plane of the bubble. This geometrical model yields predictions for the length of wrinkles in good agreement with experiments, independently of the rheological properties of the adsorbed layer

Clinical investigations concerning the use of Ethrane for Cesarean section

Peer Reviewe

Elastometry of deflated capsules elastic moduli from shape and wrinkle analysis

Elastic capsules, prepared from droplets or bubbles attached to a capillary (as in a pendant drop tensiometer), can be deflated by suction through the capillary. We study this deflation and show that a combined analysis of the shape and wrinkling characteristics enables us to determine the elastic properties in situ. Shape contours are analyzed and fitted using shape equations derived from nonlinear membrane-shell theory to give the elastic modulus, Poisson ratio and stress distribution of the membrane. We include wrinkles, which generically form upon deflation, within the shape analysis. Measuring the wavelength of wrinkles and using the calculated stress distribution gives the bending stiffness of the membrane. We illustrate this method on two very different capsule materials: polymerized octadecyltrichlorosilane (OTS) capsules and hydrophobin (HFBII) coated bubbles. Our results are in agreement with the available rheological data. For hydrophobin coated bubbles the method reveals an interesting nonlinear behavior consistent with the hydrophobin molecules having\ud a rigid core surrounded by a softer shell

Characterization of a Fatty Acid Synthetase from \u3ci\u3eCorynebacterium diphtheriae\u3c/i\u3e

A fatty acid synthetase from Corynebacterium diphtheriae has been purified to a specific activity of 450 nmoles of malonyl coenzyme A incorporated per min per mg. The enzyme is optimally active in 0.5 M phosphate buffer. C. diphtheriae appears to be the most primitive organism having a multienzyme complex for fatty acid synthesis

Stabilizing Developmental Language Trajectories in Infants/Toddlers: A Preliminary Study

Parents’ interactions with their children can have influential effects on children’s language outcomes. Special supports may be needed however, when young children live in poverty and show developmental delays early in life. This study analyzed data for a subset of children enrolled in Early Head Start programs and participating in a randomized trial of the Getting Ready intervention (Sheridan, Marvin, Knoche, & Edwards, 2008). These 41 children had standard scores below 85 on the Bayley Scales of Infant Development-II when the EHS and intervention services began. Statistically significant benefits were observed for the 28 children in the treatment group compared to the 13 children in a comparison group on children’s scores on the Preschool Language Scale-4. These preliminary findings suggest that the Getting Ready intervention may provide added value to Early Head Start programs and stabilize children’s developmental trajectory for language skills for children experiencing the dual challenges of poverty and developmental delays early in life

“More time. More showing. More helping. That’s how it sticks”: The Perspectives of Early Childhood Coachees

Coaching is a form of consultation used in early childhood settings to support positive outcomes for young children and families. While some research shows the effectiveness of coaching on practice and outcomes, little information is available on the experiences and perspectives of “coachees” as recipients of coaching support. The purpose of this study was to understand, from the coachees’ point of view, the benefits and challenges of participating in an early childhood coaching relationship. Twenty-one parents, preschool teachers and childcare providers who had engaged in coaching relationships participated in interviews and completed surveys regarding their experiences and perspectives. Data were thematically analyzed. Five overall themes, and sixteen subthemes, emerged as salient to the experiences of these coachees: (1) qualities of the coach; (2) resources provided by the coach; (3) qualities of the coach-coachee relationship; (4) coachee transformation; and (5) challenges to the coaching process. This in-depth, qualitative examination of coachees’ experiences revealed a powerful story of the transformative nature of their partnerships with their coaches. The study has implications for hiring early childhood coaches, planning professional development activities for EC coaches, and implementing models of early childhood coaching

An exploratory study of early childhood coaches’ practices and professional learning needs

Coaching is increasingly being used as a mechanism to improve the quality of early childhood education. Yet, for coaching outside of researcher-controlled interventions, limited information details coaches’ reports of their practices’ professional learning needs. We addressed this gap via an exploratory study utilizing online questionnaires of 91 coaches working with educators in a Midwestern US state across 12 coaching initiatives. Most participants had less than 5 years of experience working as an early childhood coach. Almost a third coached for multiple initiatives. Coaching occurred via multiple formats and often addressed behavior management and social emotional development regardless of the coaching initiative. Coaches identified challenges regarding scheduling and working with difficult learners and reported that peer support and being coached themselves were the most beneficial learning experiences. Findings suggest that the perspective of the coach is important in informing training and professional learning for both coaches and educators

What Is the Landscape of Early Childhood Coaching in Nebraska?

Background on Early Childhood Coaching in Nebraska Coaches have become an integral component of supporting teachers and adults working with young children and families nationally (Schachter, 2015). In the state of Nebraska, early childhood (EC) coaching has increasingly become important for this type of work (Jayaraman, Knoche, Marvin, & Bainter, 2014). Indeed, multiple initiatives within the state utilize coaches as a mechanism for supporting change in adult learners that leads to positive outcomes for young children and families. In general, coaching is a unique form of professional development that is relationship-based, whereby coaches work one-on-one or in small groups with adult learners to improve knowledge, skills, and dispositions (Aikens & Akers, 2011). Coaching can take place in adults’ immediate context and tends to be ongoing rather than a single, one-time training (Joyce & Showers, 1980; Rush & Shelden, 2005). As such, coaching has the potential to provide high-quality learning experiences for adults to support high-quality experiences in EC. Based on this growing use of coaching across the state, key stakeholders have collaborated to develop mechanisms that support coach training and development. Since this collaborative work began in 2009–10, a semiannual coach training was developed to provide foundational coaching skills and competencies relevant for all coaching initiatives, such as developing relationships and facilitating coaching conversations. The collaborative group also came to understand that coaches needed ongoing support and initiated the offering of regular “booster” sessions to support coaches’ professional development once they are in the field and actively serving coachees. In efforts to better understand who was coaching and perceptions of the training coaches received, stakeholders conducted an initial survey in 2014 (Jayaraman et al. 2014). Results of this survey (n = 35) revealed that coaches liked the work of coaching and, in particular, coaches commented that they enjoyed building relationships with coachees and observing positive changes. Although these coaches were generally positive about the training they received, myriad challenges were also reported, particularly with regards to the coaching process and their own training and professional development needs. Present Study Since the 2014 study, coaching in various EC initiatives has grown across the state. In 2018, the Nebraska Early Childhood Coach Collaboration team was interested in reassessing the process of coaching in Nebraska. This included understanding who is doing the work of coaching, what constitutes the coaching process, how coaches perceive their work, and how coaches were prepared to do their work. Thus, a new survey was created to understand more about coaching in the state of Nebraska. It contained a variety of questions consisting of both fixed-choice and open-response comments. Data collection was led by Dr. Schachter from the University of Nebraska–Lincoln and was reviewed by the Institutional Review Board. Participants were invited by email to complete an online survey that took approximately 20 minutes to complete. The survey was emailed to key stakeholders in the Spring of 2018 with requests that the survey be forwarded to anyone doing the work of EC coaching in Nebraska. In total, 101 individuals completed the survey. Importantly, all participants self-identified as a “coach.” Participants were able to enter into a raffle to win one of five iPad minis. Survey responses were analyzed descriptively. Next, we present our findings regarding who are the coaches, what is the content of coaching, how coaches perceive their work, how coaches know that coaching is working, and how coaches were prepared. We conclude with recommendations for advancing the work of coaching in the state of Nebraska

Stationary shapes of deformable particles moving at low Reynolds numbers

Lecture Notes of the Summer School ``Microswimmers -- From Single Particle Motion to Collective Behaviour'', organised by the DFG Priority Programme SPP 1726 (Forschungszentrum J{\"{u}}lich, 2015).Comment: Pages C7.1-16 of G. Gompper et al. (ed.), Microswimmers - From Single Particle Motion to Collective Behaviour, Lecture Notes of the DFG SPP 1726 Summer School 2015, Forschungszentrum J\"ulich GmbH, Schriften des Forschungszentrums J\"ulich, Reihe Key Technologies, Vol 110, ISBN 978-3-95806-083-

OXIDATION RATES OF MAJOR FATTY ACIDS IN FASTING NEONATAL PIGS

Thirty-two pigs were used to compare the oxidation rates of uniformly labeled (U-14C) palmitic (16:0), stearic (18:0), oleic (18:1) and linoleic (18:2) acids in fasting neonatal pigs. The pigs were allowed to nurse the sow for 24 to 48 h following birth. Subsequently, they were removed, an indwelling catheter was surgically placed in the external iliac vein and the pigs were fasted for 12 h to attain a postabsorptive state. The 14C fatty acids were administered as a single infusion (10 / μCi) via the catheter, and recovery of the label as expired 14CO2 was determined at 45-min intervals for a 6-h period. Blood samples were taken following the infusion (15, 60, 120, 240, 360 min) to monitor activity maintained within the free fatty acid (FFA) fraction of the plasma pool. The oxidation rate of each fatty acid was corrected for the difference in dose dilution using a uniform factor based on plasma concentration of 18:1. The cumulative 6-h 14CO2 recovery rates (percentage of dose) were 19.1, 6.6, 30.1 and 13.1% for 16:0, 18:0, 18:1 and 18:2, respectively. Oleic acid was oxidized at a more (P\u3c.05) rapid rate than the other fatty acids. Palmitic acid and 18:2 were oxidized more rapidly than 18:0, although the difference between 18:0 and 18:2 was not significant. Plasma FFA pools differed with respect to the proportion of infused activity remaining at various times after administration. At 60 and 120 min postinfusion, the greatest (P\u3c.05) proportion of activity was maintained in the 18:1 pool (11.9 and 6.6%, respectively, vs 7.7 and 4.3% for 16:0, 6.9 and 3.9% for 18:2 and 3.6 and 2.2% for 18:0). Palmitic acid and 18:2 had a greater (P\u3c.05) level of activity in the plasma FFA pool at 60 min than did 18:0. This same pattern was observed through 2 h, but by 240 min postinfusion, the proportion of activity remaining in each of the plasma pools was similar. Rate of oxidation appeared to correspond with plasma concentration and proportion of activity remaining in the plasma FFA pool