362 research outputs found
Macroporous materials: microfluidic fabrication, functionalization and applications
This article provides an up-to-date highly comprehensive overview (594 references) on the state of the art of the synthesis and design of macroporous materials using microfluidics and their applications in different fields
Parity Breaking in Nematic Tactoids
We theoretically investigate under what conditions the director field in a
spindle-shaped nematic droplet or tactoid obtains a twisted, parity-broken
structure. By minimizing the sum of the bulk elastic and surface energies, we
show that a twisted director field is stable if the twist and bend elastic
constants are small enough compared to the splay elastic constant, but only if
the droplet volume is larger than some minimum value. We furthermore show that
the transition from an untwisted to a twisted director-field structure is a
sharp function of the various control parameters. We predict that suspensions
of rigid, rod-like particles cannot support droplets with a parity broken
structure, whereas they could possibly occur in those of semi-flexible,
worm-like particles.Comment: 20 pages, 9 figures, submitted to Journal of Physics: Condensed
Matte
Mesoscale simulations of surfactant dissolution and mesophase formation
The evolution of the contact zone between pure surfactant and solvent has
been studied by mesoscale simulation. It is found that mesophase formation
becomes diffusion controlled and follows the equilibrium phase diagram
adiabatically almost as soon as individual mesophases can be identified,
corresponding to times in real systems of order 10 microseconds.Comment: 4 pages, 2 figures, ReVTeX
Vapour-liquid coexistence in many-body dissipative particle dynamics
Many-body dissipative particle dynamics is constructed to exhibit
vapour-liquid coexistence, with a sharp interface, and a vapour phase of
vanishingly small density. In this form, the model is an unusual example of a
soft-sphere liquid with a potential energy built out of local-density dependent
one-particle self energies. The application to fluid mechanics problems
involving free surfaces is illustrated by simulation of a pendant drop.Comment: 8 pages, 6 figures, revtex
Polymers pushing Polymers: Polymer Mixtures in Thermodynamic Equilibrium with a Pore
We investigate polymer partitioning from polymer mixtures into nanometer size
cavities by formulating an equation of state for a binary polymer mixture
assuming that only one (smaller) of the two polymer components can penetrate
the cavity. Deriving the partitioning equilibrium equations and solving them
numerically allows us to introduce the concept of "polymers-pushing-polymers"
for the action of non-penetrating polymers on the partitioning of the
penetrating polymers. Polymer partitioning into a pore even within a very
simple model of a binary polymer mixture is shown to depend in a complicated
way on the composition of the polymer mixture and/or the pore-penetration
penalty. This can lead to enhanced as well as diminished partitioning, due to
two separate energy scales that we analyse in detail.Comment: 10 pages, 6 figure
SPEKTRALANALYTISCHE AUSWERTUNG SPANNUNGSOPTISCHER BILDER
Two hypotheses have been proposed about the etiology of neurodevelopmental learning disorders, such as dyslexia and dyscalculia: representation impairments and disrupted access to representations. We implemented a multi-method brain imaging approach to directly investigate these representation and access hypotheses in dyscalculia, a highly prevalent but understudied neurodevelopmental disorder in learning to calculate. We combined several magnetic resonance imaging methods and analyses, including univariate and multivariate analyses, functional and structural connectivity. Our sample comprised 24 adults with dyscalculia and 24 carefully matched controls. Results showed a clear deficit in the non-symbolic magnitude representations in parietal, temporal and frontal regions, as well as hyper-connectivity in visual brain regions in adults with dyscalculia. Dyscalculia in adults was thereby related to both impaired number representations and altered connectivity in the brain. We conclude that dyscalculia is related to impaired number representations as well as altered access to these representations.ISSN:1053-8119ISSN:1095-957
How simple can a model of an empty viral capsid be? Charge distributions in viral capsids
We investigate and quantify salient features of the charge distributions on
viral capsids. Our analysis combines the experimentally determined capsid
geometry with simple models for ionization of amino acids, thus yielding the
detailed description of spatial distribution for positive and negative charge
across the capsid wall. The obtained data is processed in order to extract the
mean radii of distributions, surface charge densities and dipole moment
densities. The results are evaluated and examined in light of previously
proposed models of capsid charge distributions, which are shown to have to some
extent limited value when applied to real viruses.Comment: 10 pages, 10 figures; accepted for publication in Journal of
Biological Physic
Meat safety in Tanzania’s value chain : experiences, explanations and expectations in butcheries and eateries
This research was funded by the Biotechnology and Biological Sciences Research Council, the Department for International Development, the Economic and Social Research Council, the Medical Research Council, the Natural Environment Research Council, and the Defence Science and Technology Laboratory, under the UK Zoonoses and Emerging Livestock Systems Initiative (Grant Numbers BB/L017679/1 and BB/L018926/1).Urbanisation is associated with changes in consumption patterns and food production processes. These patterns and processes can increase or decrease the risks of outbreaks of foodborne diseases and are generally accompanied by changes in food safety policies and regulations about food handling. This affects consumers, as well as people economically engaged in the food value chain. This study looks at Tanzania’s red meat value chain—which in its totality involves about one third of the population—and focuses on the knowledge, attitudes and reported practices of operators of butcheries and eateries with regards to meat safety in an urban and in a rural environment. We interviewed 64 operators about their experiences with foodborne diseases and their explanations and expectations around meat safety, with a particular emphasis on how they understood their own actions regarding food safety risks vis-à -vis regulations. We found operators of eateries emphasising their own agency in keeping meat safe, whereas operators of butcheries—whose products are more closely inspected—relied more on official inspections. Looking towards meat safety in the future, interviewees in rural areas were, relative to their urban counterparts, more optimistic, which we attribute to rural operators’ shorter and relatively unmediated value chains.Publisher PDFPeer reviewe
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