Proton radiography to improve proton radiotherapy: Simulation study at different proton beam energies

To improve the quality of cancer treatment with protons, a translation of X-ray Computed Tomography (CT) images into a map of the proton stopping powers needs to be more accurate. Proton stopping powers determined from CT images have systematic uncertainties in the calculated proton range in a patient of typically 3-4\% and even up to 10\% in region containing bone~\cite{USchneider1995,USchneider1996,WSchneider2000,GCirrone2007,HPaganetti2012,TPlautz2014,GLandry2013,JSchuemann2014}. As a consequence, part of a tumor may receive no dose, or a very high dose can be delivered in healthy ti\-ssues and organs at risks~(e.g. brain stem)~\cite{ACKnopf2013}. A transmission radiograph of high-energy protons measuring proton stopping powers directly will allow to reduce these uncertainties, and thus improve the quality of treatment. The best way to obtain a sufficiently accurate radiograph is by tracking individual protons traversing the phantom (patient)~\cite{GCirrone2007,TPlautz2014,VSipala2013}. In our simulations we have used an ideal position sensitive detectors measuring a single proton before and after a phantom, while the residual energy of a proton was detected by a BaF$_{2}$ crystal. To obtain transmission radiographs, diffe\-rent phantom materials have been irradiated with a 3x3~cm$^{2}$ scattered proton beam, with various beam energies. The simulations were done using the Geant4 simulation package~\cite{SAgostinelli2003}. In this study we focus on the simulations of the energy loss radiographs for various proton beam energies that are clinically available in proton radiotherapy.Comment: 6 pages, 6 figures, Presented at Jagiellonian Symposium on Fundamental and Applied Subatomic Physics, 7-12 June, 2015, Krak\'ow, Polan

Potential impacts of genetic use restriction technologies (GURTs) on agrobiodiversity and agricultural production systems

Development and application of GURT as an appropriation mechanism may potentially have considerable impact on agriculture, the environment and the food security of rural areas in developing countries. Positive impacts may include increased investments in breeding as a result of increased intellectual property protection. Increased investments may contribute to higher yields and more advanced varieties, and thus to increased food production, a more sustainable production, and better consumer products. Potential negative impacts have been identified as well. These may require further discussion and close attention by regulatory authorities

Pyridinium diaqua­bis­(methyl­enediphospho­nato-κ2 O,O′)chromate(III) tetra­hydrate

In the title complex, (C5H6N)[Cr(CH4O6P2)2(H2O)2]·4H2O, the CrIII atom, lying on an inversion centre, is coordinated by two bidentate methyl­ene diphospho­nate ligands and two water molecules in a distorted octa­hedral coordination geometry. The pyridinium cation is located on an inversion centre, with an N atom and a C atom sharing a position each at a half occupancy. A three-dimensional network is constructed by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds between the pyridin­ium cation, complex anion and uncoordinated water mol­ecules

Evaluation of nutrition care to adult patients on HAART attending primary healthcare facilities in Mpumalanga

Objectives: This study aimed to evaluate nutrition care and nursing professional knowledge received by adults on highly active antiretroviral therapy attending primary health care (PHC) facilities Design: Cross-sectional, descriptive study. Subjects and setting: The study was conducted on 263 adults and 75 nursing professionals, recruited from 19 facilities in the Mbombela sub-district, Mpumalanga. Outcome measures: Interviewer-administered questionnaires were completed for each patient. Nursing professionals completed a self-administered questionnaire. Assessment tools were completed for each facility. Results: Some 41% of patients were either overweight or obese, and most females (n = 87; 51.8%) had a BMI ≥ 25 kg/m2. Based on waist circumference, 52.7% (n = 88) of females and 8.4% (n = 8) of males showed increased risk of cardiovascular disease. Although nurses were aware of a nutrition supplementation programme, knowledge of national nutrition guidelines was inadequate. Clinical judgement, rather than eligibility criteria, was used to identify suitable patients, with 13.3% (n = 35) receiving supplementation whereas only 4.9% (n = 13) qualified. Facilities generally had sufficient equipment and fair storage conditions, but stock shortages of nutrition supplements were problematic. Conclusions: Whilst certain positive findings emerged, nutrition care could be improved, largely through adequate training and support to professional nurses. Training should focus on correct execution of assessment measurements and appropriate nutritional counselling, emphasising balanced eating, food security and prevention of over-nutrition. Nurses should be familiarised with national nutrition guidelines and have access to a constant nutrition supplementation supply. Improved monitoring and evaluation of nutrition care to adults on treatment at PHC facilities is needed

Cerebral Blood Flow in Relation to Contralateral Carotid Disease an MRA and TCD Study

AbstractObjective: to describe redistribution of cerebral blood flow in patients with severe internal carotid artery (ICA) stenoses in relation to contralateral ICA disease. Methods: sixty-six patients scheduled for carotid endarterectomy (CEA) were grouped according to severity of contralateral stenosis (<30% [group I]; 30–69% [group II]; 70–99% [group III]; occlusion [group IV]. Transcranial Doppler (TCD) and magnetic resonance angiography (MRA) investigations were performed preoperatively. Results: TCD demonstrated a reversed flow in the contralateral anterior cerebral artery (A1segment) and ophthalmic artery in three-quarters of group IV patients (p <0.0001). Group IV patients also exhibited decreased blood flow velocity in the contralateral middle cerebral artery (p =0.001). MRA showed increased ipsilateral ICA and basilar artery (BA) blood flow volumes (Q-flows) in group IV patients when compared to the other groups (p <0.001). No changes in total Q-flow (ICAs+BA) were found. Conclusions: in patients considered for CEA, the severity of the contralateral ICA disease is an important determinant of the pattern of blood flow redistribution through the anterior communicating pathway and ophthalmic artery. Significant flow redistribution through the posterior communicating pathway occurs especially in patients with contralateral ICA occlusion