1,241 research outputs found
Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring
Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scannerbeam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options. based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadro
The Relationship between both Partial and Complete Denture Wearers and the Presence of Oral Malodour and the Effect of Denture Cleansers on the Oral Microbiota
Oral malodour may be considered a substantial concern for a sizeable percentage of the general population and as such it is important for
clinicians to identify the causes of oral malodour, to treat the problem effectively.
Aim: The aim of the present study was therefore to review the published literature on the presence and perception of oral malodour
(halitosis) in patients wearing both removable partial or complete dentures and the effect of denture cleansers on the oral microbiota.
Materials & Methods: A comprehensive electronic search of databases such as PUBMED, Cochrane, Google Scholar, EmBase and Web of
Science was performed up to February 2016.
Results: 55 potentially relevant reports were identified with six studies included in the review. Of the six included papers, only one study
was randomised, and five studies were either non-randomised controlled clinical trials or, quasi randomised trials. The results from these studies
would suggest that there was an indirect association between the presence and perception of oral malodour in both RPD and complete denture
wearing patients.
Conclusions: The strength of evidence was however insufficient to draw any definitive conclusions on a potential correlation of oral
malodour in patients with RPDs
Global processes of anthropogenesis characterise the early Anthropocene in the Japanese Islands
Although many scholars date the onset of the Anthropocene to the Industrial Revolution or the post-1945 ‘Great Acceleration’, there is growing interest in understanding earlier human impacts on the earth system. Research on the ‘Palaeoanthropocene’ has investigated the role of fire, agriculture, trade, urbanisation and other anthropogenic impacts. While there is increasing consensus that such impacts were more important than previously realised, geographical variation during the Palaeoanthropocene remains poorly understood. Here, we present a preliminary comparative analysis of claims that pre-industrial anthropogenic impacts in Japan were significantly reduced by four factors: the late arrival of agriculture, an emphasis on wet-rice farming limited to alluvial plains, a reliance on seafood rather than domesticated animals as a primary source of dietary protein, and cultural ideologies of environmental stewardship. We find that none of these claims of Japanese exceptionalism can be supported by the archaeological and historical records. We make some suggestions for further research but conclude that the Japanese sequence appears consistent with global trends towards increased anthropogenic impacts over the course of the Palaeoanthropocene.Introduction Claims for Japanese environmental exceptionalism - Claim 1: late arrival of agriculture. - Claim 2: the sustainability of rice. - Claim 3: domesticated animals versus marine foods. - Claim 4: cultural ideologies of stewardship. Conclusion
A Survey of Dentists in the Management of Dentine Hypersensitivity: A Questionnaire-based Study.
OBJECTIVE: Previous studies have indicated that dentists may be uncertain about the etiology, diagnosis, and effective management of dentine sensitivity/dentine hypersensitivity (DH).: The purpose of the present study was to evaluate the knowledge and understanding of Greece-based dental professionals in treating DH.: MATERIALS AND METHODS: A 26-item questionnaire was sent to a representative sample of Greek dentists. RESULTS: Two hundred thirty questionnaires were originally provided to the participants and of the 210 questionnaires that were returned, 191 questionnaires (90 M; 86 F; mean age 36.26 years [standard deviation: 11.34]) were included for analysis, a response rate of 83% was observed. 39.8% of dentists indicated that 1 in 10 of their patients experienced discomfort from DH with 76.4% of dentists indicating that their patients initiated the conversation on DH. In contrast, 44% of the dentists indicated that they initiated the relevant conversation. 34.9% of dentists indicated that the duration of discomfort lasted up to 3 weeks and 76.4% indicated that DH had an impact on their patients' quality of life. Incorrect tooth brushing was considered to be a major etiological factor (68.6%) with "air blast" (37.3%) and "probing" (15%) as the main methods for identification. 83.6% of dentists indicated that they were confident in recommending over-the-counter products for home use. CONCLUSION: The results of this study suggest that in terms of knowledge and understanding of DH, there is still confusion concerning some aspects of the diagnosis and management of the condition
The risk for breast cancer is not evidently increased in women with hyperprolactinemia
The question has been raised whether hyperprolactinemia in humans is associated with an excess risk for breast cancer. We aimed to assess the risk of breast cancer in a previously defined large cohort of patients treated for idiopathic hyperprolactinemia or prolactinomas. Based on the pattern of drug prescriptions we identified 11,314 subjects in the PHARMO network with at least one dispensing of dopamine agonists between 1996 and 2006. Of these, 1,607 subjects were considered to have dopamine agonist—treated hyperprolactinemia based on the prescribing pattern. For the present analysis, we included only women (n = 1,342). Patients with breast cancer were identified by hospital discharge codes. Data on breast cancer incidence in the Netherlands were derived from the Dutch cancer registry. Standardized mortality ratio (SMR) was the measure of outcome to assess the association between hyperprolactinemia and breast cancer. The 1,342 patients accounted for a total of 6,576 person years. Eight patients with breast cancer during follow-up were identified. Indirect standardization with incidence proportions from the general Dutch population revealed a 7.47 expected cases. The calculated SMR for breast cancer risk in patients treated hyperprolactinemia was 1.07 (95% confidence interval 0.50–2.03). In conclusion, there is no clear evidence for increased breast cancer risk in female patients treated for either idiopathic hyperprolactinemia or prolactinomas. The uncertainty about the exact risk that is due to the relatively low number of breast cancer cases, should be overcome by pooling results in a future meta-analysis
Formal Public Health Education and Career Outcomes of Medical School Graduates
Few data are available evaluating the associations of formal public health education with long-term career choice and professional outcomes among medical school graduates. The objective of this study was to determine if formal public health education via completion of a masters of public health (MPH) degree among US medical school graduates was associated with early and long-term career choice, professional satisfaction, or research productivity.We conducted a retrospective cohort study in 1108 physicians (17.1% completed a MPH degree) who had 10–20 years of follow-up post medical school graduation. Multivariable logistic regression analyses were conducted.Compared to their counterparts with no MPH, medical school graduates with a MPH were more likely to have completed a generalist primary care residency only [relative risk (RR) 1.79, 95% confidence interval (CI) 1.35–2.29], obtain employment in an academic institution (RR 1.81; 95% CI 1.33–2.37) or government agency (RR 3.26; 95% CI 1.89–5.38), and practice public health (RR 39.84; 95% CI 12.13–107.38) or primary care (RR 1.59; 95% CI 1.18–2.05). Furthermore, medical school graduates with a MPH were more likely to conduct public health research (RR 8.79; 95% CI: 5.20–13.82), receive NIH or other federal funding (RR 3.11, 95% CI 1.74–5.33), have four or more peer-reviewed publications (RR 2.07; 95% CI 1.56–2.60), and have five or more scientific presentations (RR 2.31, 95% CI 1.70–2.98).Formal public health education via a MPH was associated with career choice and professional outcomes among physicians
Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS
The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS
Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations
- …