Cucurbit[8]uril-Regulated Nanopatterning of Binary Polymer Brushes via Colloidal Templating.

Sub-micrometer/nanoscale patterned polymer brushes are prepared by employing cucurbit[8]uril (CB[8]) as a supramolecular recognition motif to assemble functional silica colloids onto Au surfaces as a sacrificial nanopatterning template. By employing CB[8]-mediated host-guest interactions at the interface, it is possible to readily generate nanopatterned materials in aqueous media under ambient conditions.This work was supported by the Engineering Physical Science Research Council, grant EP/K028510/1; C.H. thanks BP for financial support and Y.L. is grateful for a CSC Cambridge Scholarship.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/adma.20150384

Scientific Visualization Using the Flow Analysis Software Toolkit (FAST)

Over the past few years the Flow Analysis Software Toolkit (FAST) has matured into a useful tool for visualizing and analyzing scientific data on high-performance graphics workstations. Originally designed for visualizing the results of fluid dynamics research, FAST has demonstrated its flexibility by being used in several other areas of scientific research. These research areas include earth and space sciences, acid rain and ozone modelling, and automotive design, just to name a few. This paper describes the current status of FAST, including the basic concepts, architecture, existing functionality and features, and some of the known applications for which FAST is being used. A few of the applications, by both NASA and non-NASA agencies, are outlined in more detail. Described in the Outlines are the goals of each visualization project, the techniques or 'tricks' used lo produce the desired results, and custom modifications to FAST, if any, done to further enhance the analysis. Some of the future directions for FAST are also described

Using Magnetic Activity and Galactic Dynamics to Constrain the Ages of M Dwarfs

We present a study of the dynamics and magnetic activity of M dwarfs using the largest spectroscopic sample of low-mass stars ever assembled. The age at which strong surface magnetic activity (as traced by H-alpha) ceases in M dwarfs has been inferred to have a strong dependence on mass (spectral type, surface temperature) and explains previous results showing a large increase in the fraction of active stars at later spectral types. Using spectral observations of more than 40000 M dwarfs from the Sloan Digital Sky Survey, we show that the fraction of active stars decreases as a function of vertical distance from the Galactic plane (a statistical proxy for age), and that the magnitude of this decrease changes significantly for different M spectral types. Adopting a simple dynamical model for thin disk vertical heating, we assign an age for the activity decline at each spectral type, and thus determine the activity lifetimes for M dwarfs. In addition, we derive a statistical age-activity relation for each spectral type using the dynamical model, the vertical distance from the Plane and the H-alpha emission line luminosity of each star (the latter of which also decreases with vertical height above the Galactic plane).Comment: 8 pages, 5 figures, to appear in the proceedings of IAU 258: The Ages of Star

Mechanical behaviour and environmental stability of continuous fibre-reinforced glass-ceramic matrix composites

The mechanical behaviour of three continuous Silicon carbide fibre-reinforced glass-ceramic matrix composites has been investigated at room and high temperatures. Commercially available composites with magnesium aluminosilicate, calcium aluminosilicate and barium magnesium aluminosilicate glass-ceramic matrices were considered. The materials were tested in the as-received and aged (heat-treated in a n oxidizing environment) condition. Four-point bend static tests and fiexural creep, fatigue and creep-fatigue tests were carried out a s well as a small quantity of tensile tests of aged composites. The experimental results have highlighted the importance of the carbon-rich layer at the fibre/matrix interface for obtaining "graceful" failures. At temperatures of 700 to 800 °C oxidative degradation of the interface results in significant strength reduction and a transition to brittle fracture mode. By rapid heat treatment of the materials at 1100°C for 1 h it is possible to seal the fibre ends by forming a silica "plug" which prevents oxygen ingress, retaining the carbon-rich interphase and composite behaviour. The results of the creep and creep-fatigue tests indicate low-cycle loading has a strong influence on the life of components at high temperatures

The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk. II. The Field

We report on new measurements of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs derived from Sloan Digital Sky Survey Data Release 6 photometry. The analysis incorporates ~15 million low-mass stars (0.1 ), spread over 8400 deg2. Stellar distances are estimated using new photometric parallax relations, constructed from ugriz photometry of nearby low-mass stars with trigonometric parallaxes. We use a technique that simultaneously measures Galactic structure and the stellar LF from 7 \u3c Mr \u3c 16. We compare the LF to previous studies and convert to an MF using the mass-luminosity relations of Delfosse et al. The system MF, measured over –1.0\u3c log \u3c–0.1, is well described by a lognormal distribution with = 0.25 . We stress that our results should not be extrapolated to other mass regimes. Our work generally agrees with prior low-mass stellar MFs and places strong constraints on future theoretical star formation studies

Cucurbit[8]uril-Regulated Colloidal Dispersions Exhibiting Photocontrolled Rheological Behavior.

In situ photocontrol over shear-thickening of condensed colloidal dispersions is of paramount importance in a wide range of applications including process technology and photorheological fluids. Its development and practicability, however, are hampered by the lack of well-designed photoresponsive systems. Here, a colloidal suspension whose rheological behavior is readily switchable between shear-thinning and shear-thickening using an external light stimulus is reported. This smart colloidal solution contains hybrid raspberry-like colloids prepared by employing cucurbit[8]uril as a supramolecular linker to assemble functional Fe3 O4 nanoparticles onto a silica core. The formed raspberry colloids are photoresponsive and can be reversibly disassembled under UV irradiation

A randomized trial of fish oil omega-3 fatty acids on arterial health, inflammation, and metabolic syndrome in a young healthy population

BACKGROUND: Long chain omega-3 fatty acids from fish oils (O3) are known to have beneficial effects on a number of vascular risk factors in at-risk populations. The effects of a highly bioavailable emulsified preparation on an overweight young adult population are less well known. METHODS: Young adults, age 18–30, with body mass indices (BMIs) greater than 23 (average = 28.1) were administered 1.7 g of O3 per day (N = 30) or safflower oil placebo (N = 27) in an emulsified preparation (Coromega, Inc.) for 4 weeks in a double-blind randomized design. Blood was drawn and anthropometric measurements taken before and after dosing. Hemodynamic measures (central pulse wave velocity, augmentation index, and aortic systolic blood pressure), inflammatory cytokines (IL-6, IL-8, IL-10, and tumor necrosis factor-α), red blood cell and plasma phospholipid fatty acid profiles, fasting serum lipids, glucose, and C-reactive protein were measured. RESULTS: Red cell and plasma phospholipid eicosapentaenoic acid and docosahexaenoic acid concentrations increased over the four weeks of dosing in the O3 group. Dosing with O3 did not affect central pulse wave velocity, augmentation index, or aortic systolic blood pressure. None of the five American Heart Association metabolic syndrome components improved over the dosing period. None of the inflammatory cytokines, C-reactive protein, or lipids (total or LDL cholesterol) improved over the dosing period. CONCLUSIONS: No salutary effects of O3 were observed in hemodynamic, metabolic syndrome criteria or inflammatory markers as a result of this relatively short period of administration in this relatively overweight, but healthy young adult cohort

A Gyrochronology and Microvariability Survey of the Milky Way's Older Stars Using Kepler's Two-Wheels Program

Even with the diminished precision possible with only two reaction wheels, the Kepler spacecraft can obtain mmag level, time-resolved photometry of tens of thousands of sources. The presence of such a rich, large data set could be transformative for stellar astronomy. In this white paper, we discuss how rotation periods for a large ensemble of single and binary main- sequence dwarfs can yield a quantitative understanding of the evolution of stellar spin-down over time. This will allow us to calibrate rotation-based ages beyond ~1 Gyr, which is the oldest benchmark that exists today apart from the Sun. Measurement of rotation periods of M dwarfs past the fully-convective boundary will enable extension of gyrochronology to the end of the stellar main-sequence, yielding precise ages ({\sigma} ~10%) for the vast majority of nearby stars. It will also help set constraints on the angular momentum evolution and magnetic field generation in these stars. Our Kepler-based study would be supported by a suite of ongoing and future ground-based observations. Finally, we briefly discuss two ancillary science cases, detection of long-period low-mass eclipsing binaries and microvariability in white dwarfs and hot subdwarf B stars that the Kepler Two-Wheels Program would facilitate.Comment: Kepler white pape