Temporal heterogeneity in microregional erythrocyte flux in experimental solid tumours.

Using a multichannel laser Doppler system equipped with custom-developed microprobes, we have evaluated real-time fluctuations in microregional blood flow in two experimental murine tumour systems. The results show that in both the sarcoma F and the carcinoma NT over 50% of the microregions evaluated show a fluctuation in red blood cell flux by at least a factor of 2 over a 60 min time period. Approximately 20% of the regions monitored demonstrated a change in flow by a factor of 5 or more. Within the 1 h monitoring period, approximately 20% of the changes were reversed (SaF, 21%; CaNT, 19%). The duration of change for these regions ranged from 6 to 45 min. Similar temporal fluctuations in flow were seen in anaesthetised and unanaesthetised animals, indicating that artifacts due to probe movement were minimal. These findings clearly demonstrate that fluctuations in microregional erythrocyte flux are a common feature of the experimental tumours studied

NGC 6819: testing the asteroseismic mass scale, mass loss, and evidence for products of non-standard evolution

We present an extensive peakbagging effort on Kepler data of $\sim$50 red giant stars in the open star cluster NGC 6819. By employing sophisticated pre-processing of the time series and Markov Chain Monte Carlo techniques we extracted individual frequencies, heights and linewidths for hundreds of oscillation modes. We show that the "average" asteroseismic parameter $\delta\nu_{02}$, derived from these, can be used to distinguish the stellar evolutionary state between the red giant branch (RGB) stars and red clump (RC) stars. Masses and radii are estimated using asteroseismic scaling relations, both empirically corrected to obtain self-consistency as well as agreement with independent measures of distance, and using updated theoretical corrections. Remarkable agreement is found, allowing the evolutionary state of the giants to be determined exclusively from the empirical correction to the scaling relations. We find a mean mass of the RGB stars and RC stars in NGC 6819 to be $1.61\pm0.02\,\textrm{M}_\odot$ and $1.64{\pm}0.02\,\textrm{M}_\odot$, respectively. The difference $\Delta M=-0.03\pm0.01\,\textrm{M}_\odot$ is almost insensitive to systematics, suggesting very little RGB mass loss, if any. Stars that are outliers relative to the ensemble reveal overmassive members that likely evolved via mass-transfer in a blue straggler phase. We suggest that KIC 4937011, a low-mass Li-rich giant, is a cluster member in the RC phase that experienced very high mass-loss during its evolution. Such over- and undermassive stars need to be considered when studying field giants, since the true age of such stars cannot be known and there is currently no way to distinguish them from normal stars.Comment: 21 pages, 11 figure

Proportion of infiltrating IgG-binding immune cells predict for tumour hypoxia

Macrophages can account for up to 50% of tumour mass and secrete many angiogenic factors. Furthermore, tumour hypoxia is thought to play a major role in the activation of macrophages and the regulation of angiogenesis. In this paper, we demonstrate a strong correlation between hypoxia and the recruitment of immune cells binding to IgG in 8 experimental tumours. We provide evidence that IgG binding immune cells in 3 tumour lines are predominately composed of macrophages. Reduced oxygenation may act as a stimulus for recruitment of immune cells to the tumour mass, and the detection of either IgG-positive host cells or macrophages may offer an alternative method for monitoring tumour hypoxia. © 2001 Cancer Research Campaign http://www.bjcancer.co

Variation in the frequency separations with activity and impact on stellar parameter determination

Frequency separations used to infer global properties of stars through asteroseismology can change depending on the strength and at what epoch of the stellar cycle the p-mode frequencies are measured. In the Sun these variations have been seen, even though the Sun is a low-activity star. In this paper, we discuss these variations and their impact on the determination of the stellar parameters (radius, mass and age) for the Sun. Using the data from maximum and minimum activity, we fitted an age for the Sun that differs on average by 0.2 Gyr: slightly older during minimum activity. The fitted radius is also lower by about 0.5% for the solar effective temperature during minimum.Comment: to be published in JPCS to be published in JPC

About the p-mode frequency shifts in HD 49933

We study the frequency dependence of the frequency shifts of the low-degree p modes measured in the F5V star HD 49933, by analyzing the second run of observations collected by the CoRoT satellite. The 137-day light curve is divided into two subseries corresponding to periods of low and high stellar activity. The activity-frequency relationship is obtained independently from the analysis of the mode frequencies extracted by both a local and a global peak-fitting analyses, and from a cross-correlation technique in the frequency range between 1450 microHz and 2500 microHz. The three methods return consistent results. We show that the frequency shifts measured in HD 49933 present a frequency dependence with a clear increase with frequency, reaching a maximal shift of about 2 microHz around 2100 microHz. Similar variations are obtained between the l=0 and l=1 modes. At higher frequencies, the frequency shifts show indications of a downturn followed by an upturn, consistent between the l=0 and 1 modes. We show that the frequency variation of the p-mode frequency shifts of the solar-like oscillating star HD 49933 has a comparable shape to the one observed in the Sun, which is understood to arise from changes in the outer layers due to its magnetic activity.Comment: 5 pages, 3 figures, 1 table, Accepted for publication in A\&

The onset of solar cycle 24: What global acoustic modes are telling us

We study the response of the low-degree, solar p-mode frequencies to the unusually extended minimum of solar surface activity since 2007. A total of 4768 days of observations collected by the space-based, Sun-as-a-star helioseismic GOLF instrument are analyzed. A multi-step iterative maximum-likelihood fitting method is applied to subseries of 365 days and 91.25 days to extract the p-mode parameters. Temporal variations of the l=0, 1, and 2 p-mode frequencies are then obtained from April 1996 to May 2009. While the p-mode frequency shifts are closely correlated with solar surface activity proxies during the past solar cycles, the frequency shifts of the l=0 and l=2 modes show an increase from the second half of 2007, when no significant surface activity is observable. On the other hand, the l=1 modes follow the general decreasing trend of the solar surface activity. The different behaviours between the l=0 and l=2 modes and the l=1 modes can be interpreted as different geometrical responses to the spatial distribution of the solar magnetic field beneath the surface of the Sun. The analysis of the low-degree, solar p-mode frequency shifts indicates that the solar activity cycle 24 started late 2007, despite the absence of activity on the solar surface.Comment: To be accepted by A&A (with minor revisions), 4 pages, 3 figures, 1 tabl

Screening and diagnostic assessment of neurodevelopmental disorders in a male prison

Purpose The purpose of this paper is to identify neurodevelopmental disorders and difficulties (NDD) in a male prison. The study used standardised tools to carry out screening and diagnostic assessment of the attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD) and intellectual disability (ID). Design/methodology/approach The ADHD self-report scale, 20-item autism quotient and the Learning Disability Screening Questionnaire were used to screen 240 male prisoners. Prisoners who screened positive on one or more of these scales or self-reported a diagnosis of ADHD, ASD or ID were further assessed using the diagnostic interview for ADHD in adults, adapted Autism Diagnostic Observation Schedule and the Quick Test. Findings Of the 87 prisoners who screened positive for NDD and were further assessed, 70 met the study’s diagnostic criteria for ADHD, ASD or ID. Most of those with NDD (51 per cent) had previously gone unrecognised and a high proportion (51 per cent) were identified through staff- or self-referral to the study. Originality/value The study demonstrated that improving awareness and providing access to skilled, standardised assessment within a male prison can result in increased recognition and identification of NDD