High level of 3^3He polarization of 81\% Maintained in an on-beam 3^3He spin filter using SEOP

Maintaining high levels of 3He polarization over long periods of time is important to many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments and the data quality is a function of the 3He polarization. This is the case for neutron scattering where the 3He can be used to analyze the spin of a scattered neutron beam and relatively small fluxes of polarized neutrons leads to experiment times longer than several days. Consequently the J\"ulich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3He gas in place on a typical neutron instrument. Using a polarizer device we constructed a high level of 3He polarization of 81 % \pm2% was maintained with good time stability. Such levels of polarization maintained over time will be able to reduce the measurement times for such experiments and eliminate time dependent data corrections.Comment: 4 pages 2 figure

Spin Relaxation Resonances Due to the Spin-Axis Interaction in Dense Rubidium and Cesium Vapor

Resonances in the magnetic decoupling curves for the spin relaxation of dense alkali-metal vapors prove that much of the relaxation is due to the spin-axis interaction in triplet dimers. Initial estimates of the spin-axis coupling coefficients for the dimers are 290 MHz for Rb; 2500 MHz for Cs.Comment: submitted to Physical Review Letters, text + 3 figure

Oxygen Levels Do Not Determine Radiation Survival of Breast Cancer Stem Cells

For more than a century oxygen has been known to be one of the most powerful radiosensitizers. However, despite decades of preclinical and clinical research aimed at overcoming tumor hypoxia, little clinical progress has been made so far. Ionizing radiation damages DNA through generation of free radicals. In the presence of oxygen these lesions are chemically modified, and thus harder to repair while hypoxia protects cells from radiation (Oxygen enhancement ratio (OER)). Breast cancer stem cells (BSCSs) are protected from radiation by high levels of free radical scavengers even in the presence of oxygen. This led us to hypothesize that BCSCs exhibit an OER of 1. Using four established breast cancer cell lines (MCF-7, T47D, MDA-MB-231, SUM159PT) and primary breast cancer samples, we determined the number of BCSCs using cancer stem cell markers (ALDH1, low proteasome activity), compared radiation clonogenic survival and mammosphere formation under normoxic and hypoxic conditions, and correlated these results to the expression levels of key members of the free radical scavenging systems. The number of BCSCs increased with increased aggressiveness of the cancer. This correlated with increased radioresistance (SF8Gy), and decreasing OERs. When cultured as mammospheres, breast cancer cell lines and primary samples were highly radioresistant and not further protected by hypoxia (OER∼1)

Strange bedfellows: bridging the worlds of academia, public health and the sex industry to improve sexual health outcomes

The public health response to sexually transmitted infections, particularly HIV, has been and continues to be overwhelmingly focused on risk, disease and negative outcomes of sex, while avoiding discussion of positive motivations for sex (e.g. pleasure, desire, love). Recent advocacy efforts have challenged this approach and organisations have promoted the eroticisation of safer sex, especially in the context of HIV prevention

Host plant status and damage threshold of Pea (Pisum sativum) and Celeriac (Apium graveolens var. rapaceum) for the temperate root-knot nematode Meloidogyne chitwoodi

Outdoor vegetable cultivation is an important economic activity, both for fresh consumption and for the frozen vegetable industry within Flanders, Belgium. In recent years, due to the intensive nature of vegetable cultivation in the open air, nematode problems increased. The quarantine root-knot nematode Meloidogyne chitwoodi causes economic damage to the most important arable crops and vegetables grown in Flanders. However, for some vegetable crops knowledge on host plant status and damage potential is scarce or lacking. The host sensitivity for M. chitwoodi and damage thresholds of the most commonly field-grown cultivars of pea and celeriac were determined, both in glasshouse and field conditions. The damage threshold values (T) for the relative fresh pod weight of pea were 10, 1, 0.2 and 0 J2 (100 cm(3) soil)(-1) for pea 'Cher', 'Electra', 'Geneva' and 'Pixia' respectively with up to 70% yield loss. For celeriac 'Prinz', the damage threshold was 11.0 J2 (100 cm(3) soil)(-1) with maximum 22% yield loss. Based on our pot trials, all pea cultivars were considered to be a good host with their high maximum population density (M) and maximum multiplication rate (a) values in the pot trials and reproductive factor (Rf) from the field trials. Celeriac proved to be an excellent host in the pot test but on the field the M. chitwoodi population declined. However, on plots with lowest yield a substantial number of M. chitwoodi was found in the roots. This is the first report of celeriac as host for M. chitwoodi