A parallel-plate flow chamber to study initial cell adhesion on a nanofeatured surface

Cells in the human body come across many types of information, which they respond to. Both material chemistry and topography of the surface where they adhere have an effect on cell shape, proliferation, migration, and gene expression. It is possible to create surfaces with topography at the nanometric scale to allow observation of cell-topography interactions. Previous work has shown that 100-nm-diameter pits on a 300-nm pitch can have a marked effect in reducing the adhesion of rat fibroblasts in static cultures. In the present study, a flow of cell suspension was used to investigate cell adhesion onto nanopits in dynamic conditions, by means of a parallel-plate flow chamber. A flow chamber with inner nanotopography has been designed, which allows real-time observation of the flow over the nanopits. A nanopitted pattern was successfully embossed into polymethylmethacrylate to meet the required shape of the chamber. Dynamic cell adhesion after 1 h has been quantified and compared on flat and nanopitted polymethylmethacrylate substrates. The nanopits were seen to be significantly less adhesive than the flat substrates (p<0.001), which is coherent with previous observations of static cultures

Staggered Ladder Spectra

We exactly solve a Fokker-Planck equation by determining its eigenvalues and eigenfunctions: we construct nonlinear second-order differential operators which act as raising and lowering operators, generating ladder spectra for the odd and even parity states. These are staggered: the odd-even separation differs from even-odd. The Fokker-Planck equation describes, in the limit of weak damping, a generalised Ornstein-Uhlenbeck process where the random force depends upon position as well as time. Our exact solution exhibits anomalous diffusion at short times and a stationary non-Maxwellian momentum distribution.Comment: 4 pages, 2 figure

Ergodic and non-ergodic clustering of inertial particles

We compute the fractal dimension of clusters of inertial particles in mixing flows at finite values of Kubo (Ku) and Stokes (St) numbers, by a new series expansion in Ku. At small St, the theory includes clustering by Maxey's non-ergodic 'centrifuge' effect. In the limit of St to infinity and Ku to zero (so that Ku^2 St remains finite) it explains clustering in terms of ergodic 'multiplicative amplification'. In this limit, the theory is consistent with the asymptotic perturbation series in [Duncan et al., Phys. Rev. Lett. 95 (2005) 240602]. The new theory allows to analyse how the two clustering mechanisms compete at finite values of St and Ku. For particles suspended in two-dimensional random Gaussian incompressible flows, the theory yields excellent results for Ku < 0.2 for arbitrary values of St; the ergodic mechanism is found to contribute significantly unless St is very small. For higher values of Ku the new series is likely to require resummation. But numerical simulations show that for Ku ~ St ~ 1 too, ergodic 'multiplicative amplification' makes a substantial contribution to the observed clustering.Comment: 4 pages, 2 figure

Obesity and cardiovascular risk factors: results of a unique approach to NHS health checks

The aim of the study was to evaluate health check data from an inner London borough. Haringey have taken a unique approach to NHS health checks, pairing up with the Tottenham Hotspur Foundation (THF) to offer the health checks outside of traditional GP surgeries. Between March 2014 and July 2015, 3000 health checks were carried out by the THF community health check practitioner at 25 locations in the east of the Borough. The whole group data (n=2254) were analysed, comprising of 23.4% females (50.2±8.0 years) and 76.6% males (49.4±8.0 years). Alcohol consumption in males was significantly greater in the underweight compared to all other BMI groups. The underweight/normal BMI groups had significantly lower total cholesterol levels than the overweight/obese. Blood glucose levels were significantly lower in the underweight compared to overweight/obese. QRISK2 score was significantly lower in normal and underweight compared to overweight/obese males. Blood glucose levels and QRISK2 were significantly greater in the inactive/moderately inactive groups compared to the active groups. Interventions must be sought to address diet and activity in the borough, particularly in the 40–60-year-old age group. Females and the underweight should not be forgotten. Keywords: NHS health check, Cardiovascular disease, Lifestyle risk, Obesit

Physical behaviors and fundamental movement skills in British and Iranian children: an isotemporal substitution analysis

Although the relationship between fundamental movement skills (FMS) and physical behaviours has been established; differences between countries are scarcely explored. The impact of the whole physical behaviour composition, in relation to FMS, has yet to be investigated in 9‐11y children. The aims were, to investigate the associations of substitution of physical behaviours with FMS score, to compare traditional linear regression and compositional data analysis and compare between England and Iran. Measures included accelerometer‐derived activity (sleep (SL), sedentary behaviour (SB), light physical activity (LPA), and moderate‐to‐vigorous physical activity (MVPA) and FMS, using the TGMD‐2, in 119 children (64 boys) from Iran (mean (±SD) age: 9.8±0.3y; BMI of 18.2 ±3.3kg/m2) and 139 (61 boys) children from England (mean (±SD) age: 9.5±0.6y; BMI of 17.7 ±3.1kg/m2). Isometric log‐ratio multiple linear regression models were used to discern the association between FMS and the mean activity composition, and for new compositions where fixed durations of time were reallocated from one behaviour to another, while the remaining behaviours were unchanged. In physical behaviours as a composition, FMS was significantly associated in both ethnicities. English children responded significantly positively to adding 5 or more minutes LPA at the expense of SB (FMS unit change from 0.05 [0.01,0.09] at 5 min to 0.72 [0.01, 1.34] at 60min). Adding 10 minutes or more of SL, at the expense of SB, was associated with a significant, positive change in FMS in all children. Investigation is needed to understand the composition of SB and its potential influence on FMS development

Neutral winds derived from IRI parameters and from the HWM87 wind model for the sundial campaign of September, 1986

Meridional neutral winds derived from the height of the maximum ionization of the F2 layer are compared with values from results of the HWM87 empirical neutral wind model. The time period considered is the SUNDIAL-2 campaign, 21 Sept. through 5 Oct. 1986. Winds were derived from measurements by a global network of ionosondes, as well as from similar quantities generated by the International Reference Ionosphere. Global wind patterns from the three sources are similar. Differences tend to be the result of local or transient phenomena that are either too rapid to be described by the order of harmonics of the empirical models, or are the result of temporal changes not reproduced by models based on average conditions

Reference curves for a fitness battery developed for children ages 5-12 years in England

Purpose: Reference curves have already been created for a variety of different physical testing batteries across a number of countries. Due to results differing between countries for the same sex and age, it is important that reference curves are created specific for each country. Therefore, the aim of this study was to provide reference curves for five different fitness tests that assess the core components of health related fitness within children in England. Method: Following institutional ethics approval, parental informed consent and child assent was obtained for a total of 39,199 children aged between 5 and 12 years completed tests for explosive power, agility, hand eye coordination, lower body strength and upper body strength. To calculate reference values Generalised Additive Models for Location, Scale and Shape (GAMLSS) were used. Results: Reference curves and centiles show differences in performance levels of the fitness tests between sex and age groups. These reference curves and centiles provide age and sex comparisons to enable progress monitoring of children's physical fitness competence within England and comparisons to other countries. Conclusion: Girls are outperformed from a young age group and both upper and lower body strength decreases are seen at ages nine and ten. In physical activity and health related fitness interventions, both girls and boys in Key stage two should be targeted to maintain progression and lessen the gender divide

Dynamical Mass Estimates for the Halo of M31 from Keck Spectroscopy

The last few months have seen the measurements of the radial velocities of all of the dwarf spheroidal companions to the Andromeda galaxy (M31) using the spectrographs (HIRES and LRIS) on the Keck Telescope. This paper summarises the data on the radial velocities and distances for all the companion galaxies and presents new dynamical modelling to estimate the mass of extended halo of M31. The best fit values for the total mass of M31 are between 7 and 10 x 10^{11} solar masses, depending on the details of the modelling. The mass estimate is accompanied by considerable uncertainty caused by the smallness of the dataset; for example, the upper bound on the total mass is roughly 24 x 10^{11} solar masses, while the lower bound is about 3 x 10^{11} solar masses. These values are less than the most recent estimates of the most likely mass of the Milky Way halo. Bearing in mind all the uncertainties, a fair conclusion is that the M31 halo is roughly as massive as that of the Milky Way halo. There is no dynamical evidence for the widely held belief that M31 is more massive -- it may even be less massive.Comment: In press, The Astrophysical Journal (Letters

Structure of purine nucleoside phosphorylase (DeoD) from Bacillus anthracis

Protein structures from the causative agent of anthrax (Bacillus anthracis) are being determined as part of a structural genomics programme. Amongst initial candidates for crystallographic analysis are enzymes involved in nucleotide biosynthesis, since these are recognized as potential targets in antibacterial therapy. Purine nucleoside phosphorylase is a key enzyme in the purine-salvage pathway. The crystal structure of purine nucleoside phosphorylase (DeoD) from B. anthracis has been solved by molecular replacement at 2.24 Å resolution and refined to an R factor of 18.4%. This is the first report of a DeoD structure from a Gram-positive bacterium