Shear-induced transitions and instabilities in surfactant wormlike micelles

In this review, we report recent developments on the shear-induced transitions and instabilities found in surfactant wormlike micelles. The survey focuses on the non-linear shear rheology and covers a broad range of surfactant concentrations, from the dilute to the liquid-crystalline states and including the semi-dilute and concentrated regimes. Based on a systematic analysis of many surfactant systems, the present approach aims to identify the essential features of the transitions. It is suggested that these features define classes of behaviors. The review describes three types of transitions and/or instabilities : the shear-thickening found in the dilute regime, the shear-banding which is linked in some systems to the isotropic-to-nematic transition, and the flow-aligning and tumbling instabilities characteristic of nematic structures. In these three classes of behaviors, the shear-induced transitions are the result of a coupling between the internal structure of the fluid and the flow, resulting in a new mesoscopic organization under shear. This survey finally highlights the potential use of wormlike micelles as model systems for complex fluids and for applications.Comment: 64 pages, 31 figures, 2 table

An Evaluation of “Special Educational Needs” Programmes in England

The need for education to help every child rather than focus on average attainment has become a more central part of the policy agenda in the US and the UK. Remedial programmes are often difficult to evaluate because participation is usually based on pupil characteristics that are largely unobservable to the analyst. In this paper we evaluate programmes for children with moderate levels of 'special educational needs' in England. We show that the decentralized design of the policy generates significant variations in access to remediation resources across children with similar prior levels of difficulty. However, this differential is not reflected in subsequent educational attainment - suggesting that the programme is ineffective for 'treated' children. In the second part of our analysis, we use demographic variation within schools to consider the effect of the programme on whole year groups. Our analysis is consistent with no overall effect on account of the combined direct and indirect (spillover) effects. Thus, the analysis suggests that a key way that English education purports to help children with learning difficulties is not working.education, special needs, evaluation,

Every Child Matters? An Evaluation of "Special Educational Needs" Programmes in England

The need for education to help every child rather than focus on average attainment has become a more central part of the policy agenda in the US and the UK. Remedial programmes are often difficult to evaluate because participation is usually based on pupil characteristics that are largely unobservable to the analyst. In this paper we evaluate programmes for children with moderate levels of 'special educational needs' in England. We show that the decentralized design of the policy generates significant variations in access to remediation resources across children with similar prior levels of difficulty. However, this differential is not reflected in subsequent educational attainment – suggesting that the programme is ineffective for 'treated' children. In the second part of our analysis, we use demographic variation within schools to consider the effect of the programme on whole year groups. Our analysis is consistent with no overall effect on account of the combined direct and indirect (spillover) effects. Thus, the analysis suggests that a key way that English education purports to help children with learning difficulties is not working.education, special needs, evaluation

Deuterium Fractionation: the Ariadne's Thread from the Pre-collapse Phase to Meteorites and Comets today

The Solar System formed about 4.6 billion years ago from a condensation of matter inside a molecular cloud. Trying to reconstruct what happened is the goal of this chapter. For that, we put together our understanding of Galactic objects that will eventually form new suns and planetary systems, with our knowledge on comets, meteorites and small bodies of the Solar System today. Our specific tool is the molecular deuteration, namely the amount of deuterium with respect to hydrogen in molecules. This is the Ariadne's thread that helps us to find the way out from a labyrinth of possible histories of our Solar System. The chapter reviews the observations and theories of the deuterium fractionation in pre-stellar cores, protostars, protoplanetary disks, comets, interplanetary dust particles and meteorites and links them together trying to build up a coherent picture of the history of the Solar System formation. We emphasise the interdisciplinary nature of the chapter, which gathers together researchers from different communities with the common goal of understanding the Solar System history.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

Local Clustering of Transferrin Receptors Promotes Clathrin-Coated Pit Initiation

Clathrin-mediated endocytosis (CME) is the major pathway for concentrative uptake of receptors and receptor–ligand complexes (cargo). Although constitutively internalized cargos are known to accumulate into maturing clathrin-coated pits (CCPs), whether and how cargo recruitment affects the initiation and maturation of CCPs is not fully understood. Previous studies have addressed these issues by analyzing the global effects of receptor overexpression on CME or CCP dynamics. Here, we exploit a refined approach using expression of a biotinylated transferrin receptor (bTfnR) and controlling its local clustering using mono- or multivalent streptavidin. We show that local clustering of bTfnR increased CCP initiation. By tracking cargo loading in individual CCPs, we found that bTfnR clustering preceded clathrin assembly and confirmed that bTfnR-containing CCPs mature more efficiently than bTfnR-free CCPs. Although neither the clustering nor the related changes in cargo loading altered the rate of CCP maturation, bTfnR-containing CCPs exhibited significantly longer lifetimes than other CCPs within the same cell. Together these results demonstrate that cargo composition is a key source of the differential dynamics of CCPs

Challenge of Xenotransplantation in Pediatric Heart Transplantation

Although surgical techniques have progressively improved in the field of congenital heart disease (CHD), even such as hypoplastic left heart syndrome, pediatric heart transplantation is the most effective surgical option for complex CHD and cardiomyopathy with severe heart failure. However, even now, donor heart availability has been poor in children. Although technologies for ventricular assist device (VAD) have been progressing even in children, VAD cannot grow as the pediatric recipient grows. Therefore, pediatric cardiac xenotransplantation has a great possibility to save and grow children with end-stage heart failure. In this chapter, I would like to introduce the first pediatric baboon-to-human heart transplantation and its basic animal experiments done by Bailey’s group and the following attempts for pediatric cardiac orthotopic xenotransplantation (rhesus monkey-to-baboon and pig-to-primate combination)

Cupric Oxide Nanoleaves for the Oxidative Degradation of Methyl Orange without Heating or Light

Low-cost 2D cupric oxide nanoleaves (CuO NLs) arestraightforwardly synthesized at room temperature by precipitationvarying the addition method of the alkali. No further treatments arenecessary to obtain high purity NLs. The effect of the different additionmethods of alkali on the morphological, structural, vibrational, andoptical properties is studied by field emission scanning electronmicroscopy (FESEM), X-ray diffraction (XRD), and Fourier transforminfrared (FT-IR) and ultraviolet−visible (UV−vis) spectroscopies. NLsgrown by alkali addition in a dropwise manner are on average 281, 178,and 17 nm long, wide, and thick, respectively, and composed ofcrystallites of 14 nm corresponding to the crystallographic planes (1̅11)/(002) and (111)/(200). NLs obtained by this method agglomerateforming flower-like nanostructures, exhibiting indirect band gap energy of 1.21 eV. NLs grown by alkali addition in a one-stepmanner are on average significantly bigger, being 602, 219, and 26 nm long, wide, and thick, respectively, composed of crystallites of19 and 16 nm corresponding to the crystallographic planes (1̅11)/(002) and (111)/(200), respectively. These NLs agglomeraterandomly with no predominant form observed, exhibiting indirect band gap energy of 1.39 eV. The addition method of alkali doesnot influence the average crystallite size of NLs, whereas the microstrain distribution is sensitive to the initial concentration of OH−ions. Our results suggest that an indirect electronic transition between the valence and conduction bands might be more feasiblethan a direct one. NLs grown by the one-step method present the highest efficiency as catalyst toward catalytic oxidative degradationof the methyl orange dye with no heating and without the influence of light. Finally, this catalyst is easily recycled several timespreserving its high catalytic activity.Fil: Londoño Calderon, Cesar Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Menchaca Nal, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Francois, Nora J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Pampillo, Laura Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Froimowicz, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentin