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

Whole genome sequence analysis indicates recent diversification of mammal-associated Campylobacter fetus and implicates a genetic factor associated with H2S production

cknowledgements We like to thank Emma Yee (U.S. Department of Agriculture) for the generation of sequence data, we thank James Bono (U.S. Department of Agriculture) for the generation of PacBio RS reads and thank Dr. Brian Brooks and Dr. John Devenish (Canadian Food Inspection Agency) for providing C. fetus strains and for critical review of this manuscript. Funding Publication charges for this article have been funded by Utrecht University, the Netherlands.Peer reviewedPublisher PD

Campylobacter fetus Subspecies Contain Conserved Type IV Secretion Systems on Multiple Genomic Islands and Plasmids

Acknowledgments We like to thank Dr. John Devenish and Dr. Brian Brooks (Canadian Food Inspection Agency) for providing strains. We thank Nathaniel Simon and Mary Chapman for the generation of Illumina MiSeq reads and we thank James Bono for the generation of PacBio RS reads. Funding: The authors have no support or funding to report.Peer reviewedPublisher PD

Nitrogen deposition shows no consistent negative nor positive effect on the response of forest productivity to drought across European FLUXNET forest sites

Atmospheric reactive nitrogen (N) deposition is an important driver of carbon (C) sequestration in forest ecosystems. Previous studies have focused on N-C interactions in various ecosystems; however, relatively little is known about the impact of N deposition on ecosystem C cycling during climate extremes such as droughts. With the occurrence and severity of droughts likely to be exacerbated by climate change, N deposition—drought interactions remain one of the key uncertainties in process-based models to date. This study aims to contribute to the understanding of N deposition-drought dynamics on gross primary production (GPP) in European forest ecosystems. To do so, different soil water availability indicators (Standardized Precipitation Evapotranspiration Index (SPEI), soil volumetric water) and GPP measurements from European FLUXNET forest sites were used to quantify the response of forest GPP to drought. The computed drought responses of the forest GPP to drought were linked to modelled N deposition estimates for varying edaphic, physiological, and climatic conditions. Our result showed a differential response of forest ecosystems to the drought indicators. Although all FLUXNET forest sites showed a coherent dependence of GPP on N deposition, no consistent or significant N deposition effect on the response of forest GPP to drought could be isolated. The mean response of forest GPP to drought could be predicted for forests with Pinus trees as dominant species (R2 = 0.85, RMSE = 8.1). After extracting the influence of the most prominent parameters (mean annual temperature and precipitation, forest age), however, the variability remained too large to significantly substantiate hypothesized N deposition effects. These results suggest that, while N deposition clearly affects forest productivity, N deposition is not a major nor consistent driver of forest productivity responses to drought in European forest ecosystems

Comparative Genomics of Campylobacter fetus from Reptiles and Mammals Reveals Divergent Evolution in Host-Associated Lineages

Acknowledgments The authors like to thank Brian Brooks and John Devenish (Canadian Food Inspection Agency) for providing strains and valuable suggestions.Peer reviewedPublisher PD

Mental health care use in medically unexplained and explained physical symptoms: findings from a general population study

Objective: The aim of this study was to explore mental health care utilization patterns in primary and specialized mental health care of people with unexplained or explained physicalnsymptoms. Methods: Data were derived from the first wave of the Netherlands Mental Health Surveyband Incidence Study-2, a nationally representative face-to-face cohort study among the general population aged 18–64 years. We selected subjects with medically unexplained symptoms (MUS) only (MUSonly; n=177), explained physical symptoms only (PHYonly, n=1,952), combined MUS and explained physical symptoms (MUS + PHY, n=209), and controls without physical symptoms (NONE, n=4,168). We studied entry into mental health care and the number of treatment contacts for mental problems, in both primary care and specialized mental health care. Analyses were adjusted for sociodemographic characteristics and presence of any 12-month mental disorder assessed with the Composite International Diagnostic Interview 3.0. Results: At the primary care level, all three groups of subjects with physical symptoms showed entry into care for mental health problems significantly more often than controls. The adjusted odds ratios were 2.29 (1.33, 3.95) for MUSonly, 1.55 (1.13, 2.12) for PHYonly, and 2.25 (1.41, 3.57) for MUS + PHY. At the specialized mental health care level, this was the case only for MUSonly subjects (adjusted odds ratio 1.65 [1.04, 2.61]). In both the primary and specialized mental health care, there were no significant differences between the four groups in the number of treatment contacts once they entered into treatment. Conclusion: All sorts of physical symptoms, unexplained as well as explained, were associated with significant higher entry into primary care for mental problems. In specialized mental health care, this was true only for MUSonly. No differences were found in the number of treatment contacts. This warrants further research aimed at the content of the treatment contacts