405 research outputs found

    OPTIma:a tracking solution for proton computed tomography in high proton flux environments

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    Currently there is a large discrepancy between the currents that are used for treatments in proton beam therapy facilities and the ultra low beam currents required for many proton CT imaging systems. Here we provide details of the OPTIma silicon strip based tracking system, which has been designed for performing proton CT imaging in conditions closer to the high proton flux environments of modern spot scanning treatment facilities. Details on the physical design, sensor testing, modelling, and track reconstruction are provided along with Monte-Carlo simulation studies of the expected performance for proton beam currents of up to 50 pA at the nozzle when using a σ = ∌10 mm spot scanning cyclotron system. Using a detailed simulation of the proposed OPTIma system, a discrepancy of less than 1% on the Relative Stopping Power is found for various tissues when embedded within a 150 mm diameter Perspex sphere. It is found that by accepting up to 7 protons per bunch it is possible to operate at cyclotron beam currents up to 5 times higher than would be possible with a single proton based readout, significantly reducing the total beam time required to produce an image, while also reducing the discrepancy between the beam currents required for treatment and those used for proton CT

    A new silicon tracker for proton imaging and dosimetry

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    For many years, silicon micro-strip detectors have been successfully used as tracking detectors for particle and nuclear physics experiments. A new application of this technology is to the field of particle therapy where radiotherapy is carried out by use of charged particles such as protons or carbon ions. Such a treatment has been shown to have advantages over standard x-ray radiotherapy and as a result of this, many new centres offering particle therapy are currently under construction around the world today. The Proton Radiotherapy, Verification and Dosimetry Applications (PRaVDA) consortium are developing instrumentation for particle therapy based upon technology from high-energy physics. The characteristics of a new silicon micro-strip tracker for particle therapy will be presented. The array uses specifically designed, large area sensors with technology choices that follow closely those taken for the ATLAS experiment at the HL-LHC. These detectors will be arranged into four units each with three layers in an x–u–v configuration to be suitable for fast proton tracking with minimal ambiguities. The sensors will form a tracker capable of tracing the path of ~200 MeV protons entering and exiting a patient allowing a new mode of imaging known as proton computed tomography (pCT). This will aid the accurate delivery of treatment doses and in addition, the tracker will also be used to monitor the beam profile and total dose delivered during the high fluences used for treatment. We present here details of the design, construction and assembly of one of the four units that will make up the complete tracker along with its characterisation using radiation tests carried out using a 90 Sr source in the laboratory and a 60 MeV proton beam at the Clatterbridge Cancer Centre

    Anthropology in conversation with an Islamic tradition : Emmanuel Levinas and the practice of critique

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    Funded by the Carnegie Trust for the Universities of Scotland This research was funded by the Carnegie Trust for the Universities of Scotland. I would like to thank Arnar Arnason, Alison Brown, Tim Ingold, Jo Vergunst, and the anonymous JRAI readers for their critical feedback, which greatly improved the quality and coherence of this article.Peer reviewedPostprin

    Discovery of Mycobacterium Tuberculosis Protein Tyrosine Phosphatase A (MptpA) Inhibitors Based on Natural Products and a Fragment-Based Approach

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    Naturally inspired or fragment based. Mcyobacterium tuberculosis has two functional phosphatases, protein tyrosine phosphates A and B (MptpA and B), which are thought to mediate mycobacterial survival in the host. Here we describe the first inhibitors of MptpA (see scheme). Initial hits were identified in screening collections that were inspired by natural products and composed by fragment-based approach

    Natural Products Chemistry and Taxonomy of the Marine Cyanobacterium Blennothrix cantharidosmum

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    A Papua New Guinea field collection of the marine cyanobacterium Blennothrix cantharidosmum was investigated for its cytotoxic constituents. Bioassay-guided isolation defined the cytotoxic components as the known compounds lyngbyastatins 1 and 3. However, six new acyl proline derivatives, tumonoic acids D−I, plus the known tumonoic acid A were also isolated. Their planar structures were defined from NMR and MS data, while their stereostructures followed from a series of chiral chromatographies, degradation sequences, and synthetic approaches. The new compounds were tested in an array of assays, but showed only modest antimalarial and inhibition of quorum sensing activities. Nevertheless, these are the first natural products to be reported from this genus, and this inspired a detailed morphologic and 16S rDNA-based phylogenetic analysis of the producing organism

    HFE variants and the expression of iron-related proteins in breast cancer-associated lymphocytes and macrophages

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    DisponĂ­vel em: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5264664/The association of HFE (High Iron FE) major variants with breast cancer risk and behavior has been a matter of discussion for a long time. However, their impact on the expression of iron-related proteins in the breast cancer tissue has never been addressed. In the present study, hepcidin, ferroportin 1, transferrin receptor 1 (TfR1), and ferritin expressions, as well as tissue iron deposition were evaluated in a collection of samples from breast cancers patients and analyzed according to the patients’ HFE genotype. Within the group of patients with invasive carcinoma, those carrying the p.Cys282Tyr variant in heterozygosity presented a higher expression of hepcidin in lymphocytes and macrophages than wild-type or p.His63Asp carriers. An increased expression of TfR1 was also observed in all the cell types analyzed but only in p.Cys282Tyr/p.His63Asp compound heterozygous patients. A differential impact of the two HFE variants was further noticed with the observation of a significantly higher percentage of p.Cys282Tyr heterozygous patients presenting tissue iron deposition in comparison to p.His63Asp heterozygous. In the present cohort, no significant associations were found between HFE variants and classical clinicopathological markers of breast cancer behavior and prognosis. Although limited by a low sampling size, our results provide a new possible explanation for the previously reported impact of HFE major variants on breast cancer progression, i.e., not by influencing systemic iron homeostasis but rather by differentially modulating the local cellular expression of iron-related proteins and tissue iron deposition.OM is a recipient of the PhD grant SFRH/BD/2011/78184 from Fundação para a CiĂȘncia e Tecnologia (FCT). The authors also acknowledge financial support from ICBAS/AI&NSUMIB and by national funds through FCT and MinistĂ©rio da Educação e CiĂȘncia (MEC) and when applicable co-funded by FEDER funds within the partnership agreement PT2020 related with the research unit number 4293.info:eu-repo/semantics/publishedVersio

    Identification of a human neonatal immune-metabolic network associated with bacterial infection

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    Understanding how human neonates respond to infection remains incomplete. Here, a system-level investigation of neonatal systemic responses to infection shows a surprisingly strong but unbalanced homeostatic immune response; developing an elevated set-point of myeloid regulatory signalling and sugar-lipid metabolism with concomitant inhibition of lymphoid responses. Innate immune-negative feedback opposes innate immune activation while suppression of T-cell co-stimulation is coincident with selective upregulation of CD85 co-inhibitory pathways. By deriving modules of co-expressed RNAs, we identify a limited set of networks associated with bacterial infection that exhibit high levels of inter-patient variability. Whereas, by integrating immune and metabolic pathways, we infer a patient-invariant 52-gene-classifier that predicts bacterial infection with high accuracy using a new independent patient population. This is further shown to have predictive value in identifying infection in suspected cases with blood culture-negative tests. Our results lay the foundation for future translation of host pathways in advancing diagnostic, prognostic and therapeutic strategies for neonatal sepsis

    Is home-based monitoring of ovulution to time frozen embryo transfer a cost-effective alternative for hospital-based monitoring of ovulation? Study protocol of the multicentre, non-inferiority Antarctica-2 randomised controlled trial

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    STUDY QUESTION: The objective of this trial is to compare the effectiveness and costs of true natural cycle (true NC-) frozen embryo transfer (FET) using urinary LH tests to modified NC-FET using repeated ultrasound monitoring and ovulation trigger to time FET in the NC. Secondary outcomes are the cancellation rates of FET (ovulation before hCG or no dominant follicle, no ovulation by LH urine test, poor embryo survival), pregnancy outcomes (miscarriage rate, clinical pregnancy rates, multiple ongoing pregnancy rates, live birth rates, costs) and neonatal outcomes (including gestational age, birthweight and sex, congenital abnormalities or diseases of babies born). WHAT IS KNOWN ALREADY: FET is at the heart of modern IVF. To allow implantation of the thawed embryo, the endometrium must be prepared either by exogenous oestrogen and progesterone supplementation (artificial cycle (AC)-FET) or by using the NC to produce endogenous oestradiol before and progesterone after ovulation to time the transfer of the thawed embryo (NC-FET). During an NC-FET, women visit the hospital repeatedly and receive an ovulation trigger to time FET (i.e. modified (m)NC-FET or hospital-based monitoring). From the woman’s point of view, a more natural approach using home-based monitoring of the ovulation with LH urine tests to allow a natural ovulation to time FET may be desired (true NC-FET or home-based monitoring). STUDY DESIGN, SIZE, DURATION: This is a multicentre, non-inferiority prospective randomised controlled trial design. Consenting women will undergo one FET cycle using either true NC-FET or mNC-FET based on randomisation. PARTICIPANTS/MATERIALS, SETTING, METHODS: Based on our sample size calculation, the study group will consist of 1464 women between 18 and 45 years old who are scheduled for FET. Women with anovulatory cycles, women who need ovulation induction and women with a contra indication for pregnancy will be excluded. The primary outcome is ongoing pregnancy. Secondary outcomes are cancellation rates of FET, pregnancy outcomes (including miscarriage rate, clinical pregnancy, multiple pregnancy rate and live birth rate). Costs will be estimated by counting resource use and calculating unit prices. STUDY FUNDING/COMPETING INTEREST(S): The study received a grant from the Dutch Organisation for Health Research and Development (ZonMw 843002807; www.zonmw.nl). ZonMw has no role in the design of the study, collection, analysis, and interpretation of data or writing of the manuscript. F.B. reports personal fees from member of the external advisory board for Merck Serono, grants from Research support grant Merck Serono, outside the submitted work. A.E.P.C. reports and Unrestricted grant of Ferring B.V. to the Center for Reproductive medicine, no personal fee. Author up-to-date on Hyperthecosis. Congress meetings 2019 with Ferring B.V. and Theramex B.V. M.G. reports Department research and educational grants from Guerbet, Merck and Ferring (location VUMC) outside the submitted work. E.R.G. reports personal fees from Titus Health Care, outside the submitted work. C.B.L. reports grants from Ferring, grants from Merck, from Guerbet, outside the submitted work. The other authors have none to declare. TRIAL REGISTRATION NUMBER: Dutch Trial Register (Trial NL6414 (NTR6590), https://www.trialregister.nl/). TRIAL REGISTRATION DATE: 23 July 2017 DATE OF FIRST PATIENT’S ENROLMENT: 10 April 201
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