44 research outputs found

    Hardy-Carleman Type Inequalities for Dirac Operators

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    General Hardy-Carleman type inequalities for Dirac operators are proved. New inequalities are derived involving particular traditionally used weight functions. In particular, a version of the Agmon inequality and Treve type inequalities are established. The case of a Dirac particle in a (potential) magnetic field is also considered. The methods used are direct and based on quadratic form techniques

    Getting the Grip on Nonspecific Treatment Effects: Emesis in Patients Randomized to Acupuncture or Sham Compared to Patients Receiving Standard Care

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    Background: It is not known whether or not delivering acupuncture triggers mechanisms cited as placebo and if acupuncture or sham reduces radiotherapy-induced emesis more than standard care. Methodology/Principal Findings: Cancer patients receiving radiotherapy over abdominal/pelvic regions were randomized to verum (penetrating) acupuncture (n = 109; 99 provided data) in the alleged antiemetic acupuncture point PC6 or sham acupuncture (n = 106; 101 provided data) performed with a telescopic non-penetrating needle at a sham point 2-3 times/week during the whole radiotherapy period. The acupuncture cohort was compared to a reference cohort receiving standard care (n = 62; 62 provided data). The occurrence of emesis in each group was compared after a mean dose of 27 Gray. Nausea and vomiting were experienced during the preceding week by 37 and 8% in the verum acupuncture group, 38 and 7% in the sham acupuncture group and 63 and 15% in the standard care group, respectively. The lower occurrence of nausea in the acupuncture cohort (verum and sham) compared to patients receiving standard care (37% versus 63%, relative risk (RR) 0.6, 95 % confidence interval (CI) 0.5-0.8) was also true after adjustment for potential confounding factors for nausea (RR 0.8, CI 0.6 to 0.9). Nausea intensity was lower in the acupuncture cohort (78% no nausea, 13% a little, 8% moderate, 1% much) compared to the standard care cohort (52% no nausea, 32% a little, 15% moderate, 2% much) (p = 0.002). The acupuncture cohort expected antiemetic effects from their treatment (95%). Patients who expected nausea had increased risk for nausea compared to patients who expected low risk for nausea (RR 1.6; Cl 1.2-2.4). Conclusions/Significance: Patients treated with verum or sham acupuncture experienced less nausea and vomiting compared to patients receiving standard care, possibly through a general care effect or due to the high level of patient expectancy.Original Publication:Anna Enblom, Mats Lekander, Mats Hammar, Anna Johnsson, Erik Onelov, Martin Ingvar, Gunnar Steineck and Sussanne Börjeson, Getting the Grip on Nonspecific Treatment Effects: Emesis in Patients Randomized to Acupuncture or Sham Compared to Patients Receiving Standard Care, 2011, PLOS ONE, (6), 3, .http://dx.doi.org/10.1371/journal.pone.0014766Licensee: Public Library of Science (PLoS)http://www.plos.org

    Application of Fastsim with variable coefficient of friction using twin disc experimental measurements

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    In the field of railway simulation, it is a general assumption to consider the coefficient of friction as a known and constant value. This hypothesis is clearly not correct as friction is a consequence of the operating conditions (an output, not an input) and many factors can cause friction coefficient to change. In this paper, numerical algorithms based on the simplified theory of Kalker (Fastsim) and capable of modelling variable friction are studied and improved to match experimental measurements. Experimental creep curves from twin disc measurements are used to extract the friction parameters required by the numerical algorithms. Different friction functions are tested to correlate the effect of the contaminants and the pressure on the coefficient of friction. Finally, two examples are shown to highlight the differences between modelling the wheel–rail contact with variable or constant coefficient of friction and their implications in the estimation of the interaction forces and wear.This research was supported by Universitat Politecnica de Valencia (Spain).Rovira Cardete, A.; Roda Buch, A.; Lewis, R.; Marshall, M. (2012). Application of Fastsim with variable coefficient of friction using twin disc experimental measurements. Wear. 274-275:109-126. doi:10.1016/j.wear.2011.08.019S109126274-27

    Mathematical Modelling as a Proof of Concept for MPNs as a Human Inflammation Model for Cancer Development

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    <p><b>Left:</b> Typical development in stem cells (top panel A) and mature cells (bottom panel B). Healthy hematopoietic cells (full blue curves) dominate in the early phase where the number of malignant cells (stipulated red curves) are few. The total number of cells is also shown (dotted green curves). When a stem cell mutates without repairing mechanisms, a slowly increasing exponential growth starts. At a certain stage, the malignant cells become dominant, and the healthy hematopoietic cells begin to show a visible decline. Finally, the composition between the cell types results in a takeover by the malignant cells, leading to an exponential decline in hematopoietic cells and ultimately their extinction. The development is driven by an approximately exponential increase in the MPN stem cells, and the development is closely followed by the mature MPN cells. <b>Right:</b> B)The corresponding allele burden (7%, 33% and 67% corresponding to ET, PV, and PMF, respectively) defined as the ratio of MPN mature cells to the total number of mature cells.</p

    Acupuncture compared with placebo acupuncture in radiotherapy-induced nausea-a randomized controlled study

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    It is not known if verum (real) acupuncture is effective for nausea and vomiting (emesis) during radiotherapy. We randomly treated 215 blinded cancer patients with verum: penetrating 'deqi' creating acupuncture (n = 109) or non-penetrating sham needles (n = 106) two to three times per week. The patients documented emesis daily during the radiotherapy period. Primary end point was the number of patients with at least one episode of nausea. In the verum and the sham acupuncture group, 70% and 62% experienced nausea at least once during the radiotherapy period (relative risk 1.1, 95% CI 0.9-1.4) for a mean number of 10.1 and 8.7 days. Twenty five percent and 28% vomited, and 42% and 37% used antiemetic drugs at least once, respectively. Ninety-five percent in the verum acupuncture group and 96% in the sham acupuncture group believed that the treatment had been effective against nausea. In both groups, 67% experienced positive effects on relaxation, mood, sleep or pain reduction and 89% wished to receive the treatment again. Acupuncture creating deqi is not more effective than sham in radiotherapy-induced nausea, but in this study, nearly all patients in both groups experienced that the treatment was effective for nausea
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