197 research outputs found

    LEIR electron cooler status

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    The electron cooler for LEIR is the first of a new generation of coolers being commissioned for fast phase space cooling of ion beams in storage rings. It is a stateof- the-art cooler incorporating all the recent developments in electron cooling technology (adiabatic expansion, electrostatic bend, variable density electron beam) and is designed to deliver up to 600 mA of electron current for the cooling and stacking of Pb54+ ions in the frame of the ions for LHC project. In this paper we present our experience with the commissioning of the new device as well as the first results of ion beam cooling with a high-intensity variable-density electron beam

    From Composite Indicators to Partial Orders: Evaluating Socio-Economic Phenomena Through Ordinal Data

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    In this paper we present a new methodology for the statistical evaluation of ordinal socio-economic phenomena, with the aim of overcoming the issues of the classical aggregative approach based on composite indicators. The proposed methodology employs a benchmark approach to evaluation and relies on partially ordered set (poset) theory, a branch of discrete mathematics providing tools for dealing with multidimensional systems of ordinal data. Using poset theory and the related Hasse diagram technique, evaluation scores can be computed without performing any variable aggregation into composite indicators. This way, ordinal scores need not be turned into numerical values, as often done in evaluation studies, inconsistently with the real nature of the phenomena at hand. We also face the problem of \u201cweighting\u201d evaluation dimensions, to account for their different relevance, and show how this can be handled in pure ordinal terms. A specific focus is devoted to the binary variable case, where the methodology can be specialized in a very effective way. Although the paper is mainly methodological, all of the basic concepts are illustrated through real examples pertaining to material deprivation

    Phosphorylation of the androgen receptor is associated with reduced survival in hormonerefractory prostate cancer patients

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    Cell line studies demonstrate that the PI3K/Akt pathway is upregulated in hormone-refractory prostate cancer (HRPC) and can result in phosphorylation of the androgen receptor (AR). The current study therefore aims to establish if this has relevance to the development of clinical HRPC. Immunohistochemistry was employed to investigate the expression and phosphorylation status of Akt and AR in matched hormone-sensitive and -refractory prostate cancer tumours from 68 patients. In the hormone-refractory tissue, only phosphorylated AR (pAR) was associated with shorter time to death from relapse (<i>P</i>=0.003). However, when an increase in expression in the transition from hormone-sensitive to -refractory prostate cancer was investigated, an increase in expression of PI3K was associated with decreased time to biochemical relapse (<i>P</i>=0.014), and an increase in expression of pAkt<sup>473</sup> and pAR<sup>210</sup> were associated with decreased disease-specific survival (<i>P</i>=0.0019 and 0.0015, respectively). Protein expression of pAkt<sup>473</sup> and pAR<sup>210</sup> also strongly correlated (<i>P</i><0.001, c.c.=0.711) in the hormone-refractory prostate tumours. These results provide evidence using clinical specimens, that upregulation of the PI3K/Akt pathway is associated with phosphorylation of the AR during development of HRPC, suggesting that this pathway could be a potential therapeutic target

    Combinatorial Markov chains on linear extensions

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    We consider generalizations of Schuetzenberger's promotion operator on the set L of linear extensions of a finite poset of size n. This gives rise to a strongly connected graph on L. By assigning weights to the edges of the graph in two different ways, we study two Markov chains, both of which are irreducible. The stationary state of one gives rise to the uniform distribution, whereas the weights of the stationary state of the other has a nice product formula. This generalizes results by Hendricks on the Tsetlin library, which corresponds to the case when the poset is the anti-chain and hence L=S_n is the full symmetric group. We also provide explicit eigenvalues of the transition matrix in general when the poset is a rooted forest. This is shown by proving that the associated monoid is R-trivial and then using Steinberg's extension of Brown's theory for Markov chains on left regular bands to R-trivial monoids.Comment: 35 pages, more examples of promotion, rephrased the main theorems in terms of discrete time Markov chain

    Change in Markers of Bone Metabolism with Chemotherapy for Advanced Prostate Cancer: Interleukin-6 Response Is a Potential Early Indicator of Response to Therapy

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    Men with androgen-independent prostate cancer (AIPC) frequently have bone metastasis. The effects of chemotherapy on markers of bone metabolism have not been well characterized. We conducted a prospective study of patients with AIPC randomized in the first cycle to receive either docetaxel/estramustine or zoledronic acid, a bisphosphonate, to inhibit osteoclastic activity. Here we report the effects of therapy on markers of bone metabolism in these patients following the first cycle of therapy. Serum levels of several indices of bone remodeling were evaluated using commercial enzyme-linked immunosorbent assays. Changes in markers of bone metabolism were compared in patients receiving initial chemotherapy versus bisphosphonate. There was no significant difference in median change in any of the measured bone markers in patients given zoledronic acid when compared to chemotherapy. When comparing responders to nonresponders, overall interleukin-6 (IL-6) decreased by 35% in prostate-specific antigen responders; whereas, IL-6 levels increased by 76% in nonresponders (p = 0.03). Elevated IL-6 levels and reductions in IL-6 levels early in treatment may reflect ultimate clinical response to docetaxel-based regimens.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78145/1/jir.2008.0024.pd

    Randomized Phase II trial assessing estramustine and vinblastine combination chemotherapy vs estramustine alone in patients with progressive hormone-escaped metastatic prostate cancer

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    Abstract Based on the results of combined data from three North American Phase II studies, a randomised Phase II study in the same patient population was performed, using combination chemotherapy with estramustine phosphate (EMP) and vinblastine (VBL) in hormone refractory prostate cancer patients. In all, 92 patients were randomised into a Phase II study of oral EMP (10 mg kg day continuously) or oral EMP in combination with intravenous VBL (4 mg m(2) week for 6 weeks, followed by 2 weeks rest). The end points were toxicity and PSA response in both groups, with the option to continue the trial as a Phase III study with time to progression and survival as end points, if sufficient responses were observed. Toxicity was unexpectedly high in both treatment arms and led to treatment withdrawal or refusal in 49% of all patients, predominantly already during the first treatment cycle. The mean treatment duration was 10 and 14 weeks, median time to PSA progression was 27.2 and 30.8 weeks, median survival time was 44 and 50.9 weeks, and PSA response rate was only 24.6 and 28.9% in the EMP/VBL and EMP arms, respectively. There was no correlation between PSA response and survival. While the PSA response in the patients tested was less than half that recorded in the North American studies, the toxicity of EMP monotherapy or in combination with VBL was much higher than expected. Further research on more effective and less toxic treatment strategies for hormone refractory prostate cancer is mandatory

    A phase II trial of docetaxel and erlotinib as first-line therapy for elderly patients with androgen-independent prostate cancer

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    Background: Docetaxel is the standard first-line agent for the treatment of androgen-independent prostate cancer (AIPC). The combination of docetaxel with molecularly targeted therapies may offer the potential to increase the efficacy and decrease the toxicity of cytotoxic chemotherapy for prostate cancer. Previous studies demonstrate activation of the human epidermal growth factor receptor (EGFR) in prostate cancer. Erlotinib is a specific inhibitor of the tyrosine-kinase activity of EGFR. The goal of this study is to determine the anti-cancer activity docetaxel combined with erlotinib for the treatment of elderly subjects with AIPC. Methods: This is a multi-institutional Phase II study in patients with histologically confirmed adenocarcinoma of the prostate and age [greater than or equal to] 65 years. Patients were requred to have progressive disease despite androgen-deprivation therapy as determined by: (1) measurable lesions on cross-sectional imaging; (2) metastatic disease by radionucleotide bone imaging; or (3) elevated prostate specific antigen (PSA). Treatment cycles consisted of docetaxel 60 mg/m2 IV on day 1 and erlotinib 150 mg PO days 1-21. Patients with responding or stable disease after 9 cycles were eligible to continue on erlotinib alone as maintenance therapy. Results: Characteristics of 22 patients enrolled included: median age 73.5 years (range, 65-80); median Karnofsky Performance Status 90 (range 70-100); median hemoglobin 12.1 g/dl (range, 10.0-14.3); median PSA 218.3 ng/ml (range, 9-5754). A median of 6 treatment cycles were delivered per patient (range 1-17). No objective responses were observed in 8 patients with measurable lesions (0%, 95% CI 0-31%). Bone scan improvement and PSA decline was seen in 1 patient (5%, 95% CI 0.1-25%). Five of 22 patients experienced [greater than or equal to] 50% decline in PSA (23%, 95% CI 8-45%). Hematologic toxicity included grade 3 neutropenia in 9 patients and neutropenic fever in 2 patients. Common non-hematologic toxicities ([greater than or equal to] grade 3) included fatigue, anorexia, and diarrhea. Conclusion: Docetaxel/erlotinib can be delivered safely in elderly patients with AIPC. Anti-cancer disease activity appears generally comparable to docetaxel when used as monotherapy. Hematologic and nonhematologic toxicity may be increased over docetaxel monotherapy. Prospective randomized studies would be required to determine if the toxicity of docetaxel and erlotinib justifies its use in this setting.This study was supported by NIH Prostate SPORE P50 CA92131 to DBA. Phase One Foundation to MEG and DBA
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