We report a new method for the production of ordered 3D metal-nanowire network fi lms. The method utilizes a coating of lipid inverse cubic phase as the template for electrodeposition. We have produced platinum fi lms which show a previously unreported "single diamond" nanoarchitecture with Fd3m symmetry and a lattice parameter of approximately 132 Å. Their electrochemically accessible surface area is estimated to be > 40 m 2 g − 1 . The new methodology represents a facile route to 3D cubic nanostructures and thus provides a synthetically attractive route to the preparation of 3D nanostructured devices with diverse potential applications.Nanostructured metals and semiconductors have many important technological uses. They are commonly produced by templating soft materials such as diblock copolymers [ 1 ] or lyotropic liquid-crystal phases that form by amphiphile selfassembly. [ 2 ] These soft templates exhibit a range of different nanostructures that include hexagonal phases, based on simple 2D arrays of cylinders, and the more complex 3D bicontinuous cubic structures, based on mathematical surfaces known as the triply periodic minimal surfaces. Three different symmetries of bicontinuous cubic structure have been reported, based on the gyroid (G), double diamond (D), and primitive (P) minimal surfaces, which correspond to the space groups Ia3d (Q 230 ), Pn3m (Q 224 ), and Im3m (Q 229 ), respectively. In the inverse (Type II) cubic phases whose use as an electrochemical template is described here, the minimal surface lies at the centre of a continuous amphiphile bilayer which separates two continuous, but non-intersecting, water channel networks.Direct electrodeposition of nanostructured materials from normal topology (Type I) lyotropic liquid-crystal phases was fi rst reported by Attard and co-workers in 1997. [ 3 ] The method represents a reliable route to a range of nanostructured materials [ 4 ] under conditions that are suffi ciently mild to preserve the lyotropic mesophase structure during the electrodeposition process. Reported uses of direct electrochemical lyotropic templating using the normal (Type I) hexagonal phase are numerous, but in contrast there is only one reported case involving electrochemical templating from normal topology cubic phases. [ 5 ] There are two main reasons for this: fi rst, the cubic phase typically occupies only a small region of the composition-temperature phase diagram, and second, perhaps more importantly, the bicontinuous cubic phases are much more viscous than their hexagonal counterparts; [ 6 ] the combined result being that electrochemical templating from a cubic phase via the true liquid-crystal templating route is very difficult to achieve in practice.Nonetheless, the production of nanostructured materials with a bicontinuous cubic morphology is highly desirable, and even though the lyotropic liquid-crystal templating route has not been used extensively in this way, some alternative (albeit multi-step) approaches have been reported in the literature. The resulting bicon...

Lipid cubic phases are complex nanostructures that form naturally in a variety of biological systems, with applications including drug delivery and nanotemplating. Most X-ray scattering studies on lipid cubic phases have used unoriented polydomain samples as either bulk gels or suspensions of micrometer-sized cubosomes. We present a method of investigating cubic phases in a new form, as supported thin films that can be analyzed using grazing incidence small-angle X-ray scattering (GISAXS). We present GISAXS data on three lipid systems: phytantriol and two grades of monoolein (research and industrial). The use of thin films brings a number of advantages. First, the samples exhibit a high degree of uniaxial orientation about the substrate normal. Second, the new morphology allows precise control of the substrate mesophase geometry and lattice parameter using a controlled temperature and humidity environment, and we demonstrate the controllable formation of oriented diamond and gyroid inverse bicontinuous cubic along with lamellar phases. Finally, the thin film morphology allows the induction of reversible phase transitions between these mesophase structures by changes in humidity on subminute time scales, and we present time-resolved GISAXS data monitoring these transformations.

Inverse bicontinuous cubic (Q II) phases are nanostructured materials formed by lipid self-assembly. We have successfully imaged thin films of hydrated Q(II) phases from two different systems using AFM. The images show periodic arrays of water channels with spacing and symmetry consistent with published SAXS data on the bulk materials.

Persistence length is the foremost measure of DNA flexibility. Its origins lie in polymer theory which was adapted for DNA following the determination of B-DNA structure in 1953. There is no single definition of persistence length used, and the links between published definitions are based on assumptions which may, or may not be, clearly stated. DNA flexibility is affected by local ionic strength, solvent environment, bound ligands and intrinsic sequence-dependent flexibility. This article is a review of persistence length providing a mathematical treatment of the relationships between four definitions of persistence length, including: correlation, Kuhn length, bending, and curvature. Persistence length has been measured using various microscopy, force extension and solution methods such as linear dichroism and transient electric birefringence. For each experimental method a model of DNA is required to interpret the data. The importance of understanding the underlying models, along with the assumptions required by each definition to determine a value of persistence length, is highlighted for linear dichroism data, where it transpires that no model is currently available for long DNA or medium to high shear rate experiments.

On January 20 and 21, 2020, ASAPbio, in collaboration with EMBL-EBI and Ithaka S+R, convened over 30 representatives from academia, preprint servers, publishers, funders, and standards, indexing and metadata infrastructure organisations at EMBL-EBI (Hinxton, UK) to develop a series of recommendations for best practices for posting and linking of preprints in the life sciences and ideally the broader research community. We hope that these recommendations offer guidance for new preprint platforms and projects looking to enact best practices and ultimately serve to improve the experience of using preprints for all.