Trains, tails and loops of partially adsorbed semi-flexible filaments

Polymer adsorption is a fundamental problem in statistical mechanics that has direct relevance to diverse disciplines ranging from biological lubrication to stability of colloidal suspensions. We combine experiments with computer simulations to investigate depletion induced adsorption of semi-flexible polymers onto a hard-wall. Three dimensional filament configurations of partially adsorbed F-actin polymers are visualized with total internal reflection fluorescence microscopy. This information is used to determine the location of the adsorption/desorption transition and extract the statistics of trains, tails and loops of partially adsorbed filament configurations. In contrast to long flexible filaments which primarily desorb by the formation of loops, the desorption of stiff, finite-sized filaments is largely driven by fluctuating filament tails. Simulations quantitatively reproduce our experimental data and allow us to extract universal laws that explain scaling of the adsorption-desorption transition with relevant microscopic parameters. Our results demonstrate how the adhesion strength, filament stiffness, length, as well as the configurational space accessible to the desorbed filament can be used to design the characteristics of filament adsorption and thus engineer properties of composite biopolymeric materials

Crystal-to-crystal transition of ultrasoft colloids under shear

Ultrasoft colloids typically do not spontaneously crystallize, but rather vitrify, at high concentrations. Combining in-situ rheo-SANS experiments and numerical simulations we show that shear facilitates crystallization of colloidal star polymers in the vicinity of their glass transition. With increasing shear rate well beyond rheological yielding, a transition is found from an initial bcc-dominated structure to an fcc-dominated one. This crystal-to-crystal transition is not accompanied by intermediate melting but occurs via a sudden reorganization of the crystal structure. Our results provide a new avenue to tailor colloidal crystallization and crystal-to-crystal transition at molecular level by coupling softness and shear

Verblijfsregeling voor slachtoffers van mensenhandel en oneigenlijk gebruik: Een verkennende studie in het Verenigd Koninkrijk, Italië en België

__Abstract__ Verschillende Europese landen hebben regelingen getroffen waardoor (vermoede-lijke) slachtoffers van mensenhandel in aanmerking kunnen komen voor verblijf, begeleiding en opvang. In Nederland staat deze regeling bekend als de B9-rege- ling. Hier is het recht op tijdelijk verblijf en bescherming in principe afhankelijk van de medewerking van slachtoffers aan de opsporing en vervolging van de mensenhandelaar. Ook het recht op voortgezet verblijf is onder andere gekoppeld aan de vervolging van de dader(s) voor mensenhandel of een daaraan gerelateerd delict. Sinds enkele jaren zijn er in Nederland onder een aantal betrokkenen zorgen over mogelijk oneigenlijk gebruik van de B9-regeling. Hoewel er geen data beschikbaar zijn over de omvang van de problematiek, geven een aantal betrokkenen bij vooral de politie en het OM signalen af dat er vreemdelingen zijn die een mensenhandel-verhaal fingeren om gebr

Kinetic pathways of the Nematic-Isotropic phase transition as studied by confocal microscopy on rod-like viruses

We investigate the kinetics of phase separation for a mixture of rodlike viruses (fd) and polymer (dextran), which effectively constitutes a system of attractive rods. This dispersion is quenched from a flow-induced fully nematic state into the region where the nematic and the isotropic phase coexist. We show experimental evidence that the kinetic pathway depends on the overall concentration. When the quench is made at high concentrations, the system is meta-stable and we observe typical nucleation-and-growth. For quenches at low concentration the system is unstable and the system undergoes a spinodal decomposition. At intermediate concentrations we see the transition between both demixing processes, where we locate the spinodal point.Comment: 11 pages, 6 figures, accepted in J. Phys.: Condens. Matter as symposium paper for the 6th Liquid Matter Conference in Utrech

The benefits of theory for clinical practice:Cognitive treatment for chronic low back pain patients as an illustrative example

Purpose. To demonstrate, with the help of an example of cognitive treatment for patients with chronic low back pain, how a systematic description of the content and theoretical underpinnings of treatment can help to improve clinical practice. Methods. A conceptual analysis, two types of theories, and a programme-theory framework were instrumental in systematically specifying the content of the treatment and the underlying assumptions. Results. A detailed description of the cognitive treatment, including: (i) The intended outcomes; (ii) the related treatment components; (iii) the therapeutic process that is expected to mediate between outcomes and components, (iv) the conditions for optimal application; and (v) the guiding principles. Conclusions. The systematic description of the treatment revealed important issues for clinical practice, such as the patient and therapist characteristics that are needed for optimal provision of cognitive treatment. The discussions on the role of theory in rehabilitation practice are taken one step further in this clinical commentary: instead of simply describing the problems, we also demonstrated a means to tackle them

Annual Report of the Municipal Officers of the Town of Columbia Falls For The Municipal Year 1935-1936

status: publishe

Political debates on Islamic headscarves and civic integration abroad in France and in the Netherlands: What can models explain?

Cities, Migration and Global Interdependenc