A design path for the hierarchical self-assembly of patchy colloidal particles.

Patchy colloidal particles are promising candidates for building blocks in directed self-assembly. To be successful the surface patterns need to be simple enough to be synthesized, while feature-rich enough to cause the colloidal particles to self-assemble into desired structures. Achieving this is a challenge for traditional synthesis methods. Recently it has been suggested that surface patterns themselves can be made to self-assemble. In this paper we present a design path for the hierarchical targeted self-assembly of patchy colloidal particles based on self-assembling surface patterns. At the level of the surface structure, we use a predictive method utilizing the universality of stripes and spots, coupled with stoichiometric constraints, to cause highly specific and functional patterns to self-assemble on spherical surfaces. We use a minimalistic model of an alkanethiol on gold as a demonstration, showing that even with limited control over the interaction between surface constituents we can obtain patterns that cause the colloidal particles themselves to self-assemble into various complex geometric structures, such as strings, membranes, cubic aggregates and colloidosomes, as well as various crystalline patterns.

Using the uncertainty principle to design simple interactions for targeted self-assembly.

We present a method that systematically simplifies isotropic interactions designed for targeted self-assembly. The uncertainty principle is used to show that an optimal simplification is achieved by a combination of heat kernel smoothing and Gaussian screening of the interaction potential in real and reciprocal space. We use this method to analytically design isotropic interactions for self-assembly of complex lattices and of materials with functional properties. The derived interactions are simple enough to narrow the gap between theory and experimental implementation of theory based designed self-assembling materials.

Chiral surfaces self-assembling in one-component systems with isotropic interactions.

We show that chiral symmetry can be broken spontaneously in one-component systems with isotropic interactions, i.e., many-particle systems having maximal a priori symmetry. This is achieved by designing isotropic potentials that lead to self-assembly of chiral surfaces. We demonstrate the principle on a simple chiral lattice and on a more complex lattice with chiral supercells. In addition, we show that the complex lattice has interesting melting behavior with multiple morphologically distinct phases that we argue can be qualitatively predicted from the design of the interaction.

Novel self-assembled morphologies from isotropic interactions.

We present results from particle simulations with isotropic medium range interactions in two dimensions. At low temperature novel types of aggregated structures appear. We show that these structures can be explained by spontaneous symmetry breaking in analytic solutions to an adaptation of the spherical spin model. We predict the critical particle number where the symmetry breaking occurs and show that the resulting phase diagram agrees well with results from particle simulations.

Designing isotropic interactions for self-assembly of complex lattices.

We present a direct method for solving the inverse problem of designing isotropic potentials that cause self-assembly into target lattices. Each potential is constructed by matching its energy spectrum to the reciprocal representation of the lattice to guarantee that the desired structure is a ground state. We use the method to self-assemble complex lattices not previously achieved with isotropic potentials, such as a snub square tiling and the kagome lattice. The latter is especially interesting because it provides the crucial geometric frustration in several proposed spin liquids.

Dissociated incretin hormone response to protein versus fat ingestion in obese subjects.

Protein elicits a stronger early (30 min) glucose-dependent insulinotropic polypeptide (GIP) response than fat ingestion in lean individuals, with no difference in glucagon-like peptide-1 (GLP-1). We assessed the incretin hormone response to protein versus fat ingestion in obesity. Equicaloric (8 kcal/kg) fat (olive oil) or protein (whey protein) was ingested by non-diabetic obese male volunteers [body mass index (BMI) >30 kg/m(2) ; n = 12] and plasma GIP and GLP-1 were determined. We found no difference in the early GIP or GLP-1 responses to fat versus protein. However, the total 300-min GIP response was greater after fat than after protein ingestion (20.3 ± 3.9 vs. 10.0 ± 2.8 nmol/l × min; p = 0.026), whereas the 300-min GLP-1 responses were the same. Thus, in obesity, protein and fat ingestion elicit similar early (30 min) incretin hormone responses, whereas 300-min GIP secretion is more pronounced after fat than protein ingestion.

[Quality assurance of drug prescription in primary health care. A new database software makes the drug therapy surveillance easier]. / Kvalitetsarbete kring läkemedelsförskrivning i primärvården. Nytt databasprogram underlättar uppföljning av läkemedelsbehandling.

Quality assurance of drug prescription is a pre-requisite for rational drug use. From 22 health-care centres in the south-western area of the Stockholm County Council region, drug-prescription data were obtained from the patients' computerised medical recordings. This could be done with the aid of a specially designed database program. The drug-prescription data from the 22 health-care centres were collected and compiled in a central unit. Thereafter the results were brought back to the health-care centres, in which the quality assurance of drug prescription could be started.