'Pancake' electron distributions in the outer radiation belts

Electron pitch angle distributions sharply peaked at 90 degrees pitch angle were first recorded in the energy range 50 eV < E < 500 eV by the GEOS1 and GEOS2 spacecraft in 1977/1978, from the plasmapause out to geostationary orbit. At the time they were explained as the remnants of pitch angle diffusion driven solely by electron cyclotron harmonic (ECH) waves. Here we report new observations by the Low Energy Plasma Analyser on board the Combined Release and Radiation Effects Satellite, which measured the complete pitch angle distribution over the energy range 100 eV < E < 30 keV. The pancake distributions are seen to develop from injected distributions that are nearly isotropic in velocity space, on a timescale that is greater than 2 hours. The freshly injected distributions are associated with strong ECH and whistler mode waves suggesting that the pancake distributions are likely to be caused by a combination of both wave types. Outside L = 6.0 the fitting analysis at energies in the range 100 eV < E < 1 keV shows that in the marginally stable state the phase space density contours lie approximately along the characteristic curves for diffusion by whistler mode waves determined independently from the plasma wave data. However, inside L = 6.0, significant departures are observed. Our results suggest that whistler mode waves play a dominant role in the formation of pancake distributions outside L = 6.0, whereas inside L = 6.0 and, in particular, in the vicinity of the plasmapause, the ECH waves also play a significant role. Consequently, both types of waves should be considered in any attempt to explain the diffuse aurora and the variation with L taken into account

Screening a diverse collection of Artemisia annua germplasm accessions for the antimalarial compound, artemisinin

The anti-malarial drug artemisinin is commercially extracted from the medicinal plant Artemisia annua (L.). Here we report the screening of seventy A. annua individuals sourced from around the world, identifying individuals containing > 2% artemisinin, concentrations approximately twice as high as have been previously reported. These extremely high yielding individuals have been maintained as propagational clones, and represent promising parental lines for future A. annua breeding programmes

A randomized controlled trial to investigate the effects of intra-dialytic cycling on left ventricular mass

Cardiovascular disease is the leading cause of death for patients receiving hemodialysis. Since exercise mitigates many risk factors which drive cardiovascular disease for these patients, we assessed effects of a program of intra-dialytic cycling on left ventricular mass and other prognostically relevant measures of cardiovascular disease as evaluated by cardiac MRI (the CYCLE-HD trial). This was a prospective, open-label, single-blinded cluster-randomized controlled trial powered to detect a 15g difference in left ventricular mass measured between patients undergoing a six-month program of intra-dialytic cycling (exercise group) and patients continuing usual care (control group). Pre-specified secondary outcomes included measures of myocardial fibrosis, aortic stiffness, physical functioning, quality of life and ventricular arrhythmias. Outcomes were analyzed as intention-to-treat according to a pre-specified statistical analysis plan. Initially, 130 individuals were recruited and completed baseline assessments (65 each group). Ultimately, 101 patients completed the trial protocol (50 control group and 51 exercise group). The six-month program of intra-dialytic cycling resulted in a significant reduction in left ventricular mass between groups (-11.1g; 95% confidence interval -15.79, -6.43), which remained significant on sensitivity analysis (missing data imputed) (-9.92g; 14.68, -5.16). There were significant reductions in both native T1 mapping and aortic pulse wave velocity between groups favoring the intervention. There was no increase in either ventricular ectopic beats or complex ventricular arrhythmias as a result of exercise with no significant effect on physical function or quality of life. Thus, a six-month program of intradialytic cycling reduces left ventricular mass and is safe, deliverable and well tolerated

A randomized controlled trial to investigate the effects of intra-dialytic cycling on left ventricular mass

Cardiovascular disease is the leading cause of death for patients receiving hemodialysis. Since exercise mitigates many risk factors which drive cardiovascular disease for these patients, we assessed effects of a program of intra-dialytic cycling on left ventricular mass and other prognostically relevant measures of cardiovascular disease as evaluated by cardiac MRI (the CYCLE-HD trial). This was a prospective, open-label, single-blinded cluster-randomized controlled trial powered to detect a 15g difference in left ventricular mass measured between patients undergoing a six-month program of intra-dialytic cycling (exercise group) and patients continuing usual care (control group). Pre-specified secondary outcomes included measures of myocardial fibrosis, aortic stiffness, physical functioning, quality of life and ventricular arrhythmias. Outcomes were analyzed as intention-to-treat according to a pre-specified statistical analysis plan. Initially, 130 individuals were recruited and completed baseline assessments (65 each group). Ultimately, 101 patients completed the trial protocol (50 control group and 51 exercise group). The six-month program of intra-dialytic cycling resulted in a significant reduction in left ventricular mass between groups (-11.1g; 95% confidence interval -15.79, -6.43), which remained significant on sensitivity analysis (missing data imputed) (-9.92g; 14.68, -5.16). There were significant reductions in both native T1 mapping and aortic pulse wave velocity between groups favoring the intervention. There was no increase in either ventricular ectopic beats or complex ventricular arrhythmias as a result of exercise with no significant effect on physical function or quality of life. Thus, a six-month program of intradialytic cycling reduces left ventricular mass and is safe, deliverable and well tolerated

Enhancement of artemisinin concentration and yield in response to optimization of nitrogen and potassium supply to Artemisia annua

Background and Aims: The resurgence of malaria, particularly in the developing world, is considerable and exacerbated by the development of single-gene multi-drug resistances to chemicals such as chloroquinone. Drug therapies, as recommended by the World Health Organization, now include the use of antimalarial compounds derived from Artemisia annua – in particular, the use of artemisinin-based ingredients. Despite our limited knowledge of its mode of action or biosynthesis there is a need to secure a supply and enhance yields of artemisinin. The present study aims to determine how plant biomass can be enhanced while maximizing artemisinin concentration by understanding the plant’s nutritional requirements for nitrogen and potassium. Methods: Experiments were carried out, the first with differing concentrations of nitrogen, at 6, 31, 56, 106, 206 or 306 mg L21 being applied, while the other differing in potassium concentration (51, 153 or 301 mg L21). Nutrients were supplied in irrigation water to plants in pots and after a growth period biomass production and leaf artemisinin concentration were measured. These data were used to determine optimal nutrient requirements for artemisinin yield. Key Results: Nitrogen nutrition enhanced plant nitrogen concentration and biomass production successively up to 106 mg N L21 for biomass and 206 mg N L21 for leaf nitrogen; further increases in nitrogen had no influence. Artemisinin concentration in dried leaf material, measured by HPLC mass spectroscopy, was maximal at a nitrogen application of 106 mg L21, but declined at higher concentrations. Increasing potassium application from 51 to 153 mg L21 increased total plant biomass, but not at higher applications. Potassium application enhanced leaf potassium concentration, but there was no effect on leaf artemisinin concentration or leaf artemisinin yield. Conclusions: Artemisinin concentration declined beyond an optimal point with increasing plant nitrogen concentration. Maximization of artemisinin yield (amount per plant) requires optimization of plant biomass via control of nitrogen nutrition