Predicting sizes of hexagonal and gyroid metal nanostructures from liquid crystal templating

We describe a method to predict and control the lattice parameters of hexagonal and gyroid mesoporous materials formed by liquid crystal templating. In the first part, we describe a geometric model with which the lattice parameters of different liquid crystal mesophases can be predicted as a function of their water/surfactant/oil volume fractions, based on certain geometric parameters relating to the constituent surfactant molecules. We demonstrate the application of this model to the lamellar (LR), hexagonal (H1), and gyroid bicontinuous cubic (V1) mesophases formed by the binary Brij-56 (C16EO10)/water system and the ternary Brij-56/hexadecane/water system. In this way, we demonstrate predictable and independent control over the size of the cylinders (with hexadecane) and their spacing (with water). In the second part, we produce mesoporous platinum using as templates hexagonal and gyroid phases with different compositions and show that in each case the symmetry and lattice parameter of the metal nanostructure faithfully replicate those of the liquid crystal template, which is itself in agreement with the model. This demonstrates a rational control over the geometry, size, and spacing of pores in a mesoporous metal

Ultrathin uniform platinum nanowires via a facile route using an inverse hexagonal surfactant phase template

We present an attractive method for the fabrication of long, straight, highly crystalline, ultrathin platinum nanowires. The fabrication is simply achieved using an inverse hexagonal (HII) lyotropic liquid crystal phase of the commercial surfactant phytantriol as a template. A platinum precursor dissolved within the cylindrical aqueous channels of the liquid crystal phase is chemically reduced by galvanic displacement using stainless steel. We demonstrate the production of nanowires using the HII phase in the phytantriol/water system which we obtain either by heating to 55 °C or at room temperature by the addition of a hydrophobic liquid, 9-cis-tricosene, to relieve packing frustration. The two sets of conditions produced high aspect nanowires with diameters of 2.5 and 1.7 nm, respectively, at least hundreds of nanometers in length, matching the size of the aqueous channels in which they grow. This versatile approach can be extended to produce highly uniform nanowires from a range of metals

Molecular recognition between functionalized gold nanoparticles and healable, supramolecular polymer blends – a route to property enhancement

A new, healable, supramolecular nanocomposite material has been developed and evaluated. The material comprises a blend of three components: a pyrene-functionalized polyamide, a polydiimide and pyrene- functionalized gold nanoparticles (P-AuNPs). The polymeric components interact by forming well-defined p–p stacked complexes between p-electron rich pyrenyl residues and p-electron deficient polydiimide residues. Solution studies in the mixed solvent chloroform–hexafluoroisopropanol (6 : 1, v/v) show that mixing the three components (each of which is soluble in isolation), results in the precipitation of a supramolecular, polymer nanocomposite network. The precipitate thus formed can be re-dissolved on heating, with the thermoreversible dissolution/precipitation procedure repeatable over at least 5 cycles. Robust, self-supporting composite films containing up to 15 wt% P-AuNPs could be cast from 2,2,2- trichloroethanol. Addition of as little as 1.25 wt% P-AuNPs resulted in significantly enhanced mechanical properties compared to the supramolecular blend without nanoparticles. The nanocomposites showed a linear increase in both tensile moduli and ultimate tensile strength with increasing P-AuNP content. All compositions up to 10 wt% P-AuNPs exhibited essentially quantitative healing efficiencies. Control experiments on an analogous nanocomposite material containing dodecylamine-functionalized AuNPs (5 wt%) exhibited a tensile modulus approximately half that of the corresponding nanocomposite that incorporated 5 wt% pyrene functionalized-AuNPs, clearly demonstrating the importance of the designed interactions between the gold filler and the supramolecular polymer matrix

Encouraging independent thought and learning in first year practical classes

The transition from A-level to degree-level practical classes then to a research project, hence from dependent learner to independent researcher, is a hurdle that all students face when studying for a chemistry degree. This can be daunting so any innovations that aid this transition are of great value. At the University of Reading, the first year practical course has been redesigned to facilitate this transition by embedding independent thought and experimentation across all chemistry disciplines (introductory, organic, inorganic and physical). Examples of experiments that provide opportunities for independent student investigation, along with student perceptions of the experiments of the course, are given. Using this model for practical-class delivery, student engagement, confidence, independence and ultimately preparedness for year 2 were improved

Single-cell RNA-seq reveals transcriptomic heterogeneity mediated by host-pathogen dynamics in lymphoblastoid cell lines

Lymphoblastoid cell lines (LCLs) are generated by transforming primary B cells with Epstein-Barr virus (EBV) and are used extensively as model systems in viral oncology, immunology, and human genetics research. In this study, we characterized single-cell transcriptomic profiles of five LCLs and present a simple discrete-time simulation to explore the influence of stochasticity on LCL clonal evolution. Single-cell RNA sequencing (scRNA-seq) revealed substantial phenotypic heterogeneity within and across LCLs with respect to immunoglobulin isotype; virus-modulated host pathways involved in survival, activation, and differentiation; viral replication state; and oxidative stress. This heterogeneity is likely attributable to intrinsic variance in primary B cells and host-pathogen dynamics. Stochastic simulations demonstrate that initial primary cell heterogeneity, random sampling, time in culture, and even mild differences in phenotype-specific fitness can contribute substantially to dynamic diversity in populations of nominally clonal cells

Variation of serum hyaluronan with activity in individuals with knee osteoarthritis

PURPOSE: Serum hyaluronan (HA) was evaluated for diurnal variation in participants with osteoarthritis (OA) of the knee. METHODS: Twenty participants with radiographic OA of at least one knee were admitted overnight to the General Clinical Research Center for serial serum sampling. Serum was obtained between 6:00 p.m. and 8:00 p.m. on Day 1 (T3) after a day of normal activity. During the night of bed rest, participants remained supine for a minimum of 5 h between the hours of 3:00 a.m. and 8:00 a.m. Blood was drawn prior to arising from bed (T0), and 1h (T1) and 4 h (T2) after arising and performing usual morning activities, including eating breakfast. During the morning, participants were encouraged to remain physically active and were not permitted to sit for more than 30 min at a time. Serum HA was measured by enzyme-linked immunosorbent assay. Results were analyzed using non-parametric Freidman's test with Dunn's post-hoc Multiple Comparison test. RESULTS: Serum levels of HA increased significantly from T0 to T1 (P < 0.01). There were no other significant changes in serum HA levels observed between any of the other time points. CONCLUSIONS: Although a rise in serum HA with activity and eating has been demonstrated previously in individuals with rheumatoid arthritis, this is the first study to demonstrate a similar rise in individuals with OA. These results suggest that serum sampling for HA in OA clinical trials should be performed more than 1h after arising in the morning and at least 1h after breaking an overnight fast