54 research outputs found

    Micelle fragmentation and wetting in confined flow

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    We use coarse-grained molecular-dynamics (MD) simulations to investigate the structural and dynamical properties of micelles under non-equilibrium Poiseuille flow in a nano-confined geometry. The effects of flow, confinement, and the wetting properties of die-channel walls on spherical sodium dodecyl sulfate (SDS) micelles are explored when the micelle is forced through a die-channel slightly smaller than its equilibrium size. Inside the channel, the micelle may fragment into smaller micelles. In addition to the flow rate, the wettability of the channel surfaces dictates whether the micelle fragments and determines the size of the daughter micelles: The overall behavior is determined by the subtle balance between hydrodynamic forces, micelle-wall interactions and self-assembly forces

    A Molecular Simulation Study on Micelle Fragmentation and Wetting in Nano-Confined Channels

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    We performed coarse-grained molecular-dynamics (MD) simulations to study the structural and dynamical properties of surfactant micelles in equilibrium and under Poiseuille-like flow in a nano-confined geometry. We used the MARTINI force-field to model the interactions between water molecules, counter-ions, and sodium dodecyl sulfate (SDS) surfactants. SDS surfactant was chosen as the standard model because of its potential application in drug delivery systems. First, we focused on the self-assembly of SDS in equilibrium. To form stable spherical mi- celles, we ran simulations in the isothermal-isobaric ensemble (NPT) on a system of free SDS surfactants, counter-ions and water molecules. We studied the aggregation number, shape and radius of the SDS micelles in equilibrium. These results agree well with all-atom simulations of SDS. Second, we studied the spreading of a spherical micelle on a solid surface over various interaction strengths in a system consisting of a spherical SDS micelle, and counter-ions in the vicinity of a surface and water molecules. The interaction energies between walls and surfac- tants were parameterized at three distinct levels corresponding to non-, low-, and high-wetting walls surfaces. The wetting properties of the surfaces were determined by calculating the con- tact angles of the micelle on the surface in equilibrium. We calculated the contact angle from Young’s equation through measuring the surfaces tension of wall-water, wall-SDS, and water- SDS. As the micelle interacts with the surface, it either forms a cap, a bulb-shape structure, or detaches itself and floats away on high-, low-, and non-wetting surfaces respectively. Third, we explored the effect of flow, confinement, and wetting on SDS micelles when the micelle is forced through a channel slightly smaller than its equilibrium size. We performed simulations on micellar solutions confined in a die geometry in the isothermal ensemble (NVT). We show that the flowing micelle adopts different shapes to pass through the channel. Inside the channel, the micelle may fragment into smaller micelles. We demonstrate that in addition to the flow rate, the wettability of the channel surface dictates whether the micelle fragments and determines the size of daughter micelles

    The Use of Videoconferencing for Lactation Consultation: A Cross-Sectional Survey of Acceptance among Independent Samples of Mothers and Infant Fathers/Maternal Partners in the United States

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    Background: Breastfeeding is a health behavior encouraged by Healthy People 2020. However, an important barrier to breastfeeding is limited access to specialized support if needed. The use of videoconferencing technology to increase access to the relatively small number of professionals trained to manage breastfeeding issues may ultimately assist with increasing breastfeeding duration and exclusivity rates. Understanding the perceived acceptability of videoconferencing technology among potential users is a critical first step in developing effective interventions. Objectives: The objectives of this study were 1) to assess the relationship between acceptance of remote lactation consultation using videoconferencing and a) acceptance subscales, b) maternal learning style preferences and c) maternal demographic factors and, 2) to explore the relationship between infant fathers’/maternal partners’ demographic factors and their perception of their wives’/partners’ acceptance remote lactation consultation using videoconferencing. Methods: This was a cross-sectional study design using online survey methodology. Participants included 101 mothers and 80 unrelated infant fathers/maternal partners. Samples were recruited between July 2014 and March 2015, from specific and discrete randomized states. Mothers were English-speaking, ≥ 18 years of age, with an infant of ≤ 4 months of age who had been breast-fed at least once. Results: Mothers’ survey - Factors related to maternal acceptance included ‘perceived ease of use’ (r=0.680, p\u3c0.001), ‘perceived usefulness/extrinsic motivation’ (r=0.774, p\u3c0.001), and ‘intrinsic motivation’ (r=0.689, p\u3c0.001). Learning style preferences and demographics were not significantly related to maternal acceptance. Only ‘perceived usefulness/extrinsic motivation’ and maternal age predicted acceptance in the regression model (R2 [square]=0.616, p\u3c0.001). Infant fathers’/maternal partners’ survey - Factors related to infant fathers’/maternal partners’ perception of their wives’/partners’ acceptance included ‘perceived ease of use’ (r=0.653, p\u3c0.001), ‘perceived usefulness/extrinsic motivation’ (r=0.797, p\u3c0.001), and ‘intrinsic motivation’ (r=0.756, p\u3c0.001). None of the infant fathers’/maternal partners’ demographic factors were significantly different based on their perception of the acceptance of their wives/partners. Only ‘perceived usefulness/extrinsic motivation’ remained predictive in the regression (R2=0.635, p\u3c0.001). Conclusions: In these samples, mothers’ acceptance was slightly positive and infant fathers/maternal partners perceived their wives’/partners’ acceptance to be neutral. In both samples, those perceiving videoconferencing to be useful for lactation consultation showed greater acceptance of its use

    Development of a Healthful Weight Management Nutrition Education Curriculum for Low-Income Adults

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    Food Talk: Better U (FTBU) is a healthful weight management curriculum developed by the University of Georgia\u27s Supplemental Nutrition Assistance Program Education (SNAP-Ed) team. FTBU addresses the high burden of obesity among low-income Georgians by focusing on healthful weight management practices. Topics include practicing portion control, tracking dietary intake, setting goals, limiting added sugar, making small healthful behavior shifts, and implementing problem-solving strategies. Lesson structure includes sharing sessions, didactic lessons, cooking demonstrations, and physical activity. FTBU is based on needs assessment results and rigorous evaluation and thereby aligns with requirements outlined in current SNAP-Ed guidance materials. Other Extension SNAP-Ed providers may benefit from understanding the FTBU development and evaluation processes

    Robust Prescribed Trajectory Tracking Control of a Robot Manipulator Using Adaptive Finite-Time Sliding Mode and Extreme Learning Machine Method

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    peer reviewedThis study aims to provide a robust trajectory tracking controller which guarantees the prescribed performance of a robot manipulator, both in transient and steady-state modes, experiencing parametric uncertainties. The main core of the controller is designed based on the adaptive finite-time sliding mode control (SMC) and extreme learning machine (ELM) methods to collectively estimate the parametric model uncertainties and enhance the quality of tracking performance. Accordingly, the global estimation with a fast convergence rate is achieved while the tracking error and the impact of chattering on the control input are mitigated significantly. Following the control design, the stability of the overall control system along with the finite-time convergence rate is proved, and the effectiveness of the proposed method is investigated via extensive simulation studies. The results of simulations confirm that the prescribed transient and steady-state performances are obtained with enough accuracy, fast convergence rate, robustness, and smooth control input which are all required for practical implementation and applications

    Investigation of Antibacterial Effect of Cuminum cyminum and Carum carvi against Streptococcus mutans and Streptococcus pyogenes

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    Background: Streptococcus mutans is major cause of tooth decay. In addition, there is some report about effects of Streptococcus pyogenes on odontogenic infections. Herbal drugs is now administrating for treatment of some disease. The aim of this study was to evaluate the antibacterial effect of Cuminum cyminum and Carum carvi against Streptococcus mutans and Streptococcus pyogenes.Materials and Methods: In this study, standard strains of Streptococcus mutans and Streptococcus pyogenes were used, and ethanolic extract was prepared in the microbiological laboratory of Shahid Beheshti University of Medical Sciences. The experiment was repeated 6 times and chlorohexine 2% was used as a control.Results: The best effect of Carum carvi was on Streptococcus mutans, whereas on Streptococcus pyogenes both extracts of Cuminum cyminum and Carum carvi showed the same effect.Conclusion: This study showed, due to the fact that the Cuminum cyminum and Carum carvi extracts exhibited excellent antibacterial properties, they could be a suitable candidate in compounds such as mouthwash, toothpastes and Gums. Therefore, could be used in the prevention and treatment of future oral and dental diseases

    Lessons Learned Adapting and Implementing Another Organization’s Program to Promote Healthy Aging

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    Programming which promotes healthy aging may be lacking in states where nutrition and health interventions are directed earlier in life. Due to Maryland’s increasing aging population, a team of 10 University of Maryland Extension Family and Consumer Sciences educators received permission to adapt and implement the Iowa Department of Public Health’s, in partnership with the Iowa Department of Human Services and Department on Aging, Fresh Conversations program to fit the needs of Maryland’s older adults. The purpose of this manuscript is not to discuss research findings but rather to share our challenges, successes, and recommendations for adapting and implementing another state’s multi-session program to meet the needs of individual states’ communities. Specifically, we discovered communicating with partnering sites, offering food tastings, accommodating various food cultures/traditions, following the original program design, and efficiently collecting data or programmatic form responses needed careful consideration. Despite the challenges we encountered, we expanded our national and state partnerships; reached 2,836 educational contacts across the state; and developed a detailed planning, implementation, and evaluation protocol and training, which is being used as a template for other statewide program efforts

    Profil Anak Jalanan di Daerah Bekas Lokalisasi Balong Cangkring Mojokerto

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    The most dominant factor causing street children is due to family economic problems that are not able to meet the necessities of life. Apart from economic factors, the family can also be relied on by cultural, social, and parental education factors that are still low so that they cannot motivate children to live better lives. The income that street children earn varies depending on the time on the road and the type of work they choose. The average income of street children is around Rp. 50,000, - up to Rp. 100.000, - with a choice of professions as buskers, hawkers, and car glass cleaners. The spots for street children are mostly found, which are blocked by red lights or other places such as the center of the situation. The behavior of active and passive assisted members is no different, but when compared to passive members, it is very easy for active members and is directed to a better pattern of behavior. The purpose of this research is to look at the background of street children in Balong Cangkring which is focused on the reasons for being street children; income; a gathering place; and the behavior of active and passive assisted members. This research uses qualitative research with a case study approach, descriptive analysis techniques, semi-structured interviews and semi-participant observation. Participants were taken by using purposive sampling technique as many as 8 respondents
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