10,080 research outputs found

    From splashing to bouncing: the influence of viscosity on the impact of suspension droplets on a solid surface

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    We experimentally investigated the splashing of dense suspension droplets impacting a solid surface, extending prior work to the regime where the viscosity of the suspending liquid becomes a significant parameter. The overall behavior can be described by a combination of two trends. The first one is that the splashing becomes favored when the kinetic energy of individual particles at the surface of a droplet overcomes the confinement produced by surface tension. This is expressed by a particle-based Weber number WepWe_p. The second is that splashing is suppressed by increasing the viscosity of the solvent. This is expressed by the Stokes number StSt, which influences the effective coefficient of restitution of colliding particles. We developed a phase diagram where the splashing onset is delineated as a function of both WepWe_p and StSt. A surprising result occurs at very small Stokes number, where not only splashing is suppressed but also plastic deformation of the droplet. This leads to a situation where droplets can bounce back after impact, an observation we are able to reproduce using discrete particle numerical simulations that take into account viscous interaction between particles and elastic energy

    The Philadelphia School of Occupational Therapy: A Centennial Lesson

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    The Philadelphia School of Occupational Therapy (P.S.O.T.) was one of five founding occupational therapy academic programs in the United States. The program was led by two powerful occupational therapists, Helen S. Willard and Clare S. Spackman, for nearly a half century. After 60 years, P.S.O.T. was closed. This article provides a historical overview of the progression of occupational therapy education in the United States over the last century, using the story of P.S.O.T as a case study. The historical legacy and lesson from P.S.O.T. is that excellence in today’s academy may not mean security. Historically relevant today, the interaction between education and societal demands is explored, starting from the founders of the National Society for the Promotion of Occupational Therapy in 1917, through the World Wars, and casting forward. Curricular expansion, the addition of accreditation requirements, financial concerns, and faculty research requirements are presented as influential to the history of occupational therapy education. Lessons for current occupational therapy educational programs are discussed

    A Role for PPARβ/δ in Tumor Stroma and Tumorigenesis

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    Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) is a transcription factor that is activated by endogenous fatty acid ligands and by synthetic agonists. Its role in the regulation of skeletal muscle fatty acid catabolism, glucose homeostasis, and cellular differentiation has been established in multiple studies. On the contrary, a role for PPARβ/δ in tumorigenesis is less clear because there are contradictory reports in the literature. However, the majority of these studies have not examined the role of PPARβ/δ in the tumor stroma. Recent evidence suggests that stromal PPARβ/δ regulates tumor endothelial cell proliferation and promotes differentiation leading to the properly orchestrated events required for tumor blood vessel formation. This review briefly summarizes the significance of these studies that may provide clues to help explain the reported discrepancies in the literature regarding the role of PPARβ/δ in tumorigenesis

    A Functional Genomics Approach to Tanshinone Biosynthesis Provides Stereochemical Insights

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    Tanshinones are abietane-type norditerpenoid quinone natural products that are the bioactive components of the Chinese medicinal herb Salvia miltiorrhiza Bunge. The initial results from a functional genomics-based investigation of tanshinone biosynthesis, specifically the functional identification of the relevant diterpene synthases from S. miltiorrhiza, are reported. The cyclohexa-1,4-diene arrangement of the distal ring poises the resulting miltiradiene for the ensuing aromatization and hydroxylation to ferruginol suggested for tanshinone biosynthesis

    Considerations Perceived by Coaches as Specific to Coaching Elite Women’s Soccer Teams

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    This study investigated challenges perceived by coaches when working with elite women’s soccer teams. Six men and four women coaches with experience in the first Norwegian League or Norwegian national team participated. Semi-structured interviews were carried out, and the data was analyzed using thematic interpretational analysis. Participants identified professionalism, early-career termination, mental characteristics, intrateam communication, romantic relationships, access to the locker rooms (men only), and team selection (women only) as the specific challenges they face when coaching these teams. The findings are discussed in relation to ensuring that good performance and development are achieved when coaching elite women’s soccer teams and helping future coaches optimize their coaching techniques when working with elite women players
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