118 research outputs found

    Über den Einfluss der Glukokortikosteroide Dexamethason, Prednisolon und Fluticason auf die BDNF – Sekretion mononukleärer Zellen des Menschen: Eine klinisch-experimentelle Studie

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    Brain derived neurotrophic factor (BDNF), der durch mononukleäre Zellen des Blutes (PBMC) sezerniert wird, wird in Zusammenhang mit neuronaler Dysfunktion beim Asthma bronchiale und anderen entzündlichen Erkrankungen gebracht. Erstmals konnte in vitro an humanen PBMC gezeigt werden, dass Glukokortikosteroide die BDNF-Sekretion, auch nach Stimulation mit TNF alpha, signifikant supprimieren. Verglichen wurde die Sekretionsleistung bei Patienten mit entzündlichen Erkrankungen und Kontrollprobanden. Beide Gruppen zeigten stimuliert und unstimuliert eine vergleichbare BDNF-Sekretion

    Synchrone Reluktanzantriebe (SynRM) – Smarte Antriebssysteme für höchste Effizienz

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    Im Industriesektor gibt es viele Anwendungen bei denen elektrische Maschinen rund um die Uhr in rauhen Umgebungen betrieben werden. Bei VEM wurden hierfür neue Antriebe entwickelt, die hohe Wirkungsgrade auf IE5 Niveau mit Robustheit, Wartungsarmut und niedrigen Anschaffungskosten kombinieren. In diesem Vortrag werden der Entwurfsprozess sowie die auf diese Weise erzielten Ergebnisse, gemessen anhand mehrerer Prototypen, präsentiert. Darüber hinaus wird der Einfluss der Fähigkeiten des Umrichters auf das Betriebsverhalten der Maschine betrachtet.In industrial applications electrical machines are often operated around the clock in rough environments. VEM developed new drives for these applications, combining robustness, low maintenance effort and low cost with highest efficiency levels (IE5). In this presentation the development process as well as the results, measured at multiple prototypes, are shown. Additionally the significance of a smart inverter is pointed out

    Synchrone Reluktanzantriebe (SynRM) – Smarte Antriebssysteme für höchste Effizienz

    Get PDF
    Im Industriesektor gibt es viele Anwendungen bei denen elektrische Maschinen rund um die Uhr in rauhen Umgebungen betrieben werden. Bei VEM wurden hierfür neue Antriebe entwickelt, die hohe Wirkungsgrade auf IE5 Niveau mit Robustheit, Wartungsarmut und niedrigen Anschaffungskosten kombinieren. In diesem Vortrag werden der Entwurfsprozess sowie die auf diese Weise erzielten Ergebnisse, gemessen anhand mehrerer Prototypen, präsentiert. Darüber hinaus wird der Einfluss der Fähigkeiten des Umrichters auf das Betriebsverhalten der Maschine betrachtet.In industrial applications electrical machines are often operated around the clock in rough environments. VEM developed new drives for these applications, combining robustness, low maintenance effort and low cost with highest efficiency levels (IE5). In this presentation the development process as well as the results, measured at multiple prototypes, are shown. Additionally the significance of a smart inverter is pointed out

    Estimation of field production profiles in case of asphaltene deposition

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    In this work, we aimed to predict possible field production scenarios in case of asphaltene deposition based on field data as well as recommend remediation and stimulation measures to mitigate the risks of asphaltene deposition in the reservoir. We considered the influence of asphaltene formation in the near-wellbore of producers on the production data without reservoir pressure maintenance system in one of the oil fields. The asphaltene envelope in the reservoir oil was obtained, and the operating conditions of the field were evaluated under the possibility of asphaltene deposition. According to the results of dynamic modeling, the pressure map was plotted and the low-pressure areas in the near-wellbore were shown, which contributes to the aggravation of the problem associated with the asphaltene envelope. Based on the geometrical features of the low-pressure area, the dependence of the permeability reduction in the near-wellbore of the production well on the operating time was obtained using the asphaltene deposition model proposed by Wang and Civan. Based on the Buckley-Leverett theory, the field production profiles were calculated with and without asphaltene deposition. A decrease in the oil rate and consequently, the decrease in cumulative oil production in the field is expected due to the damage formation by solids. Maintenance of the production level will be facilitated by treating the nearwellbore with aromatic solvents and maintaining the reservoir pressure above the asphaltene onset pressure

    Particle-particle particle-mesh method for dipolar interactions:on error estimates and efficiency of schemes with analytical differentiation and mesh interlacing

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    The interlaced and non-interlaced versions of the dipolar particle-particle particle-mesh (P3M) method implemented using the analytic differentiation scheme (AD-P3M) are presented together with their respective error estimates for the calculation of the forces, torques, and energies. Expressions for the optimized lattice Green functions, and for the Madelung self-forces, self-torques and self-energies are given. The applicability of the theoretical error estimates are thoroughly tested and confirmed in several numerical examples. Our results show that the accuracy of the calculations can be improved substantially when the approximate (mesh computed) Madelung self-interactions are subtracted. Furthermore, we show that the interlaced dipolar AD-P3M method delivers a significantly higher accuracy (which corresponds approximately to using a twice finer mesh) than the conventional method, allowing thereby to reduce the mesh size with respect to the non-interlaced version for a given accuracy. In addition, we present similar expressions for the dipolar ik-differentiation interlaced scheme, and we perform a comparison with the AD interlaced scheme. Rough tests for the relative speed of the dipolar P3M method using ik-differentiation and the interlaced/non-interlaced AD schemes show that when FFT computing time is the bottleneck, usually when working at high precisions, the interlaced AD-scheme can be several times faster than the other two schemes. For calculations with a low accuracy requirement, the interlaced version can perform worse than the ik and the non-interlaced AD schemes.All authors are grateful to the DAAD organization for providing financial support. C.H. thanks the DFG for support through the SimTech center of excellence, the ScaFaCoS collaboration, and the SFB 716, and acknowledges helpful discussions with A. Arnold and M. Pippig.Peer reviewe

    Dose-escalation using intensity-modulated radiotherapy for prostate cancer - evaluation of quality of life with and without 18F-choline PET-CT detected simultaneous integrated boost

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    <p>Abstract</p> <p>Background</p> <p>In comparison to the conventional whole-prostate dose escalation, an integrated boost to the macroscopic malignant lesion might potentially improve tumor control rates without increasing toxicity. Quality of life after radiotherapy (RT) with vs. without <sup>18</sup>F-choline PET-CT detected simultaneous integrated boost (SIB) was prospectively evaluated in this study.</p> <p>Methods</p> <p>Whole body image acquisition in supine patient position followed 1 h after injection of 178-355MBq <sup>18</sup>F-choline. SIB was defined by a tumor-to-background uptake value ratio > 2 (GTV<sub>PET</sub>). A dose of 76Gy was prescribed to the prostate (PTV<sub>prostate</sub>) in 2Gy fractions, with or without SIB up to 80Gy. Patients treated with (n = 46) vs. without (n = 21) SIB were surveyed prospectively before (A), at the last day of RT (B) and a median time of two (C) and 19 month (D) after RT to compare QoL changes applying a validated questionnaire (EPIC - expanded prostate cancer index composite).</p> <p>Results</p> <p>With a median cut-off standard uptake value (SUV) of 3, a median GTV<sub>PET </sub>of 4.0 cm<sup>3 </sup>and PTV<sub>boost </sub>(GTV<sub>PET </sub>with margins) of 17.3 cm<sup>3 </sup>was defined. No significant differences were found for patients treated with vs. without SIB regarding urinary and bowel QoL changes at times B, C and D (mean differences ≤3 points for all comparisons). Significantly decreasing acute urinary and bowel score changes (mean changes > 5 points in comparison to baseline level at time A) were found for patients with and without SIB. However, long-term urinary and bowel QoL (time D) did not differ relative to baseline levels - with mean urinary and bowel function score changes < 3 points in both groups (median changes = 0 points). Only sexual function scores decreased significantly (> 5 points) at time D.</p> <p>Conclusions</p> <p>Treatment planning with <sup>18</sup>F-choline PET-CT allows a dose escalation to a macroscopic intraprostatic lesion without significantly increasing toxicity.</p

    Impact of age and comorbidities on health-related quality of life for patients with prostate cancer: evaluation before a curative treatment

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    <p>Abstract</p> <p>Background</p> <p>Interpretation of comparative health-related quality of life (HRQOL) studies following different prostate cancer treatments is often difficult due to differing patient ages. Furthermore, age-related changes can hardly be discriminated from therapy-related changes. The evaluation of age-and comorbidity-related changes was in focus of this study.</p> <p>Methods</p> <p>HRQOL of 528 prostate cancer patients was analysed using a validated questionnaire (Expanded Prostate Cancer Index Composite) before a curative treatment. Patients were divided into age groups ≤65, 6670, 7175 and >75 years. The impact of specific comorbidities and the Charlson Comorbidity Index (CCI) were evaluated. The questionnaire comprises 50 items concerning the urinary, bowel, sexual and hormonal domains for function and bother. For assessment of sexual and hormonal domains, only patients without prior hormonal treatment were included (n = 336).</p> <p>Results</p> <p>Urinary incontinence was observed increasingly with higher age (mean function scores of 92/88/85/87 for patients ≤65, 6670, 7175 and >75 years) complete urinary control in 78%/72%/64%/58% (p < 0.01). Sexual function scores decreased particularly (48/43/35/30), with erections sufficient for intercourse in 68%/50%/36%/32% (p < 0.01) a decrease of more than a third comparing patients ≤65 vs. 6670 (36%) and 6670 vs. 7175 years (39%). The percentage of patients with comorbidities was lowest in the youngest group (48% vs. 66%/68%/63% for ages 6670/7175/>75 years; p < 0.05). A multivariate analysis revealed an independent influence of both age and comorbidities on urinary incontinence, specifically diabetes on urinary bother, and both age and diabetes on sexual function/bother. Rectal domain scores were not significantly influenced by age or comorbidities. A CCI>5 particularly predisposed for lower urinary and sexual HRQOL scores.</p> <p>Conclusion</p> <p>Urinary continence and sexual function are the crucial HRQOL domains with age-related and independently comorbidity-related decreasing scores. The results need to be considered for the interpretation of comparative studies or longitudinal changes after a curative treatment.</p
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