94 research outputs found

    Diphosphinerhodium(I) and (ether-diphosphine)rhodium(I) complexes in homogeneous and biphasic hydroformylation of 1-hexene and in homogeneous hydrogenation of carbon dioxide

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    Im Vordergrund dieer Arbeit standen ökologische und umwelttechnische Motive, die zu Untersuchungen neuer Prozesse der homogenen und Zweiphasen-Hydroformylierung von 1-Hexen führten. Des weiteren wurde die Hydrierung von Kohlendioxid zu Ameisensäure als ein vielversprechender Weg zur Nutzung von Kohlendioxid als Rohstoffquelle untersucht. Diese Arbeit stellt die Synthese mehrerer Diphosphanliganden durch Hydrophosphinierung dar, sowie deren Komplexierung zu kationischen Rhodium(I)-Komplexen. Für die katalytische Anwendung in Wasser (Zweiphasen-Hydroformylierung) wurde die Wasserlöslichkeit von einigen dieser Liganden durch ein alternatives Konzept eingeführt, in dem Hydroxyalkoxyalkyl-Ketten an das Phosphoratom der Liganden gebunden wurde. Der zweite Teil beschäftigt sich mit der Hydrierung von Kohlendioxid zu Ameisensäure unter der Verwendung von (Ether-Diphosphan)rhodium(I)- und ihre analogen Diphosphanrhodium(I)-Komplexe, in denen der Sauerstoff der Ethereinheit durch eine Methylengruppe ersetzt wurde. Der letzte Teil behandelt die Rh-NMR-Spektroskopie als Mittel zur strukturellen Aufklärung.The necessity for better technologies due to environmental and ecological aspects are the motives of this work to investigate of 1-hexene and the hydrogenation of carbon dioxide to formic acid as a promising approach to use carbon dioxide as a raw material. This thesis presents the synthesis of a variety of diphosphine ligands by hydrophosphination provided with a C4 backbone and long or steric demanding alkyl substituents and their complexation to give cationic rhodium(I) complexes. For the catalytic application in water (biphasic hydroformylation), the water-solubility of a part of these complexes was achieved by an alternative concept in which hydroxyalkoxyalkyl chains were attached at the phosphorus atoms of the ligands. The second part of this work was dedicated to the hydrogenation of carbon dioxide to formic acid by employing (ether-diphosphine)rhodium(I) and their analogous diphosphinerhodium(I) complexes in which the oxygen atom of the ether-moiety was replaced by a methylene group. The last chapter is focused on the non-routine NMR spectroscopy of rhodium nuclei for structural elucidation

    LoopBoxes -- Evaluation of a Collaborative Accessible Digital Musical Instrument

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    LoopBoxes is an accessible digital musical instrument designed to create an intuitive access to loop based music making for children with special educational needs (SEN). This paper describes the evaluation of the instrument in the form of a pilot study during a music festival in Berlin, Germany, as well as a case study with children and music teachers in a SEN school setting. We created a modular system composed of three modules that afford single user as well as collaborative music making. The pilot study was evaluated using informal observation and questionnaires (n = 39), and indicated that the instrument affords music making for people with and without prior musical knowledge across all age groups and fosters collaborative musical processes. The case study was based on observation and a qualitative interview. It confirmed that the instrument meets the needs of the school settings and indicated how future versions could expand access to all students, especially those experiencing complex disabilities. In addition, out-of-the-box functionality seems to be crucial for the long-term implementation of the instrument in a school setting.Comment: 10 pages, 9 figures, to be published in the Proceedings of the International Conference on New Interfaces for Musical Expression (NIME'23

    Discontinuation of Palliative Brain Radiotherapy in Patients with Brain Metastases: A Case-Control Study.

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    Background: Discontinuation of radiotherapy is rarely discussed in the scientific literature. The goal of this study was, therefore, to estimate the frequency of and reasons for treatment discontinuations in patients receiving radiotherapy for brain metastases from solid tumors and to identify factors predicting said discontinuations. Methods: All patients treated for brain metastases from solid tumors between 2010 and 2020 at our institution were retrospectively reviewed. In addition to collecting relevant patient characteristics, the Recursive Partitioning Analysis (RPA) and disease-specific Graded Prognostic Assessment (GPA) groups for each patient were calculated to assess the performance of these scores in predicting treatment discontinuations. Results: Out of 468 patients who underwent cranial radiotherapy, 35 treatments (7.5%) were discontinued. The most frequent reason was clinical deterioration, which was documented in 26 (74.3%) of discontinued treatments. Patients whose radiotherapy was discontinued had, on average, more leptomeningeal disease (20.0% vs. 12.6%), worse ECOG performance status (mean ECOG performance status 1.86 vs. 1.39), and more uncontrolled extracranial metastases (85.3% vs. 70.8%). The frequencies of treatment discontinuation increased with worse prognosis and differed significantly across RPA groups (p = 0.037) but not across GPA groups (p = 0.612). Conclusions: Treatment discontinuation occurred in 7.5% of cases, mostly due to clinical deterioration. Poor performance status, as well as more advanced disease and, in turn, poor prognosis, were associated with higher discontinuation rates

    Impact of climate change on waterborne infections and intoxications

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    Progressive climate change holds the potential for increasing human health risks from waterborne infections and intoxications, e. g. through an increase in pathogen concentrations in water bodies, through the establishment of new pathogens or through possible changes in pathogen properties. This paper presents some examples of potential impacts of climate change in Germany. Non-cholera Vibrio occur naturally in seawater, but can proliferate significantly in shallow water at elevated temperatures. In the case of Legionella, climate change could lead to temporary or longer-term increased incidences of legionellosis due to the combination of warm and wet weather. Higher temperatures in piped cold water or lower temperatures in piped hot water may also create conditions conducive to higher Legionella concentrations. In nutrient-rich water bodies, increased concentrations of toxigenic cyanobacteria may occur as temperatures rise. Heavy rainfall following storms or prolonged periods of heat and drought can lead to increased levels of human pathogenic viruses being washed into water bodies. Rising temperatures also pose a potential threat to human health through pathogens causing mycoses and facultatively pathogenic micro-organisms: increased infection rates with non-tuberculous mycobacteria or fungi have been documented after extreme weather events

    Beschleunigte Alterung von Glasfasern in alkalischen Lösungen: Einflüsse auf die mechanischen Eigenschaften

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    In alkalischen Lösungen führt die Reaktion von Hydroxylionen mit den Si-O-Si-Bindungen des Glasnetzwerks zur Bildung hydratisierter Oberflächen und gelöstem Silikat. Der Grad der Korrosion bzw. der Alterung der Glasfaser ist abhängig von der chemischen Zusammensetzung des Glases und Korrosionslösung sowie von Zeit und Temperatur. Die Untersuchung von Glasfasern verschiedener chemischer Zusammensetzung in NaOH- sowie Zementlösungen zeigte, dass die inhibierende Wirkung von Ca-Ionen zu einem veränderten Korrosionsmechanismus führt. Dies konnte anhand der mechanischen Eigenschaften der Glasfasern sowie rasterelektronenmikroskopischen Untersuchungen gezeigt werden. Während die Korrosion in NaOH-Lösung zu einer ausgeprägten Umwandlung der gesamten äußeren Glasfaserschicht in Reaktionsprodukte führte, zeigten Glasfasern in Zementlösung bei gleichem pH-Wert einen stark lokal begrenzten, punktförmigen Angriff. Daraus resultieren unterschiedliche mechanische Eigenschaften der Glasfasern in Abhängigkeit von der gewählten Korrosionslösung

    Re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after initial definitive radiotherapy - A systematic review and meta-analysis of recent trials.

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    BACKGROUND There is increasing data on re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after definitive radiotherapy for prostate cancer, with increasing evidence on prostate re-irradiation using a C-arm LINAC or an MR LINAC in recent years. We therefore conducted this systematic review and meta-analysis on prostate re-irradiation including studies published from 2020 to 2023, to serve as an update on existing meta-analysis. METHODS We searched the PubMed and Embase databases in October 2023 with queries including combinations of "repeat", "radiotherapy", "prostate", "re-irradiation", "reirradiation", "re treatment", "SBRT", "retreatment". Publication date was set to be from 2020 to 2023. There was no limitation regarding language. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. After data extraction, heterogeneity testing was done by calculating the I2. A random effects model with a restricted maximum likelihood estimator was used to estimate the combined effect. Funnel plot asymmetry was assessed visually and using Egger's test to estimate the presence of publication and/or small study bias. RESULTS 14 publications were included in the systematic review. The rates of acute ≥ grade 2 (G2) genitourinary (GU) and gastrointestinal (GI) toxicities reported in the included studies ranged from 0.0-30.0 % and 0.0-25.0 % respectively. For late ≥ G2 GU and GI toxicity, the ranges are 4.0-51.8 % and 0.0-25.0 %. The pooled rate of acute GU and GI toxicity ≥ G2 were 13 % (95 % CI: 7-18 %) and 2 % (95 % CI: 0-4 %). For late GU and GI toxicity ≥ G2 the pooled rates were 25 % (95 % CI: 14-35 %) and 5 % (95 % CI: 1-9 %). The pooled 2-year biochemical recurrence-free survival was 72 % (95 % CI: 64-92 %). CONCLUSIONS SBRT in the re-irradiation of radiorecurrent prostate cancer is safe and effective. Further prospective data are warranted

    Five Fractions versus Seven Fractions SBRT for Intermediate- and High-Risk Prostate Cancer: A Propensity Score Matched Pair Analysis.

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    PURPOSE To compare two stereotactic body radiotherapy (SBRT) regimens in patients with intermediate- or high-risk prostate cancer with regards toxicity and efficacy. METHODS/MATERIAL We retrospectively collected data from 198 patients treated with SBRT for prostate cancer at two different institutions. Patients received either 35-36.25 Gy in five fractions (group A) using Cyberknife robotic platform or 42.7 Gy in seven fractions (group B) using a C-arm LINAC (image-guided). Propensity score matching was done (2:1 nearest neighbor matching without replacement), resulting in 120 patients (80 patients for group A, 40 patients for group B). Toxicity, PSA nadir, biochemical failure and disease-free survival (DFS) were analyzed. RESULTS Median follow up of all patients was 13 months (range 1-91 months). Overall, 23.3% of patients had ≥G2 acute GU toxicity (21.1% group A versus 30% group B (p = 0.222)) and 6.6% of patients ≥G2 GI toxicity (2.5% versus 15% (p = 0.010)). There was one acute G3 GU toxicity in arm A and one acute G4 rectal bleeding in group B (anticoagulated patient). Regarding late toxicity, 14.1% of patients had ≥G2 late GU toxicity (17.4% versus 6.6% (p = 0.159)) and 5.0% of patients had ≥G2 late GI toxicity (1.4% versus 13.3% (p = 0.013)). There was one G3 late GU toxicity in arm B and two G3 late GI toxicities, one in each arm. Relative median PSA reduction was 92.4% (-53.9-99.9%) from baseline PSA (93.7% (-53.9-99.9%) in group A versus 87.7% (39.8-99.9%) in group B (p = 0.043). In total, 4.2% of patients had biochemical relapse, 5.0% in group A and 2.5% in group B (p = 0.518). One-year DFS in the overall cohort was 97.3%, 98.8% in group A and 94.3% in group B (p = 0.318). CONCLUSION Both SBRT regimens have acceptable acute and late toxicity and good efficacy. There are significantly more GI toxicities in the seven-fraction regimen. Longer follow-up is warranted for better comparison of long-term efficacy

    Stereotactic Body Radiation Therapy (SBRT) as Salvage Therapy for Oligorecurrent Pleural Mesothelioma After Multi-Modality Therapy

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    Introduction: Therapy options for patients with oligoprogressive malignant pleural mesothelioma (MPM) are limited. Stereotactic Body Radiotherapy (SBRT) may be a promising therapeutic option, as it delivers a localized ablative dose of radiation and therefore balances efficacy and treatment related toxicities. The intent of this retrospective analysis was to evaluate the feasibility of SBRT for limited pleural recurrences. Methods and Materials: This retrospective single-institution study is based on the 21 consecutive patients treated with hypofractionated radiotherapy for oligoprogressive MPM. Clinical and radiological data was collected at regular follow-up visits including toxicity, local control and survival. Results: At primary diagnosis, 57% of the patients presented with stage III disease. Initial treatment of MPM consisted of induction chemotherapy (n = 12) prior to a macroscopic complete resection (n = 18). Three patients received additional intracavitary chemotherapy and another three patients were treated with chemotherapy alone without another treatment at the time of first diagnosis. A total of 50 lesions in recurrent MPM were treated with SBRT. The median number of radiotherapy fractions was 5 (range 3-20) with a median dose per fraction of 5 Gy (range 2.5-12.5 Gy). The median total treatment dose was 30 Gy (20-50 Gy) with a median prescription isodose line (IDL) of 65% (65-100%). Median follow-up of all patients from diagnosis was 28 months (range 7-152 months). Analyzing all lesions separately, the 12-months-local control from SBRT was 73.5%. The median progression free survival (PFS) after SBRT was 6 months (range 0-21 months) and the median OS from first first SBRT was 29 months (range 0-61 months). Only one patients experienced above Grade 3 toxicities. Conclusion: This analysis demonstrates the feasibility of a SBRT approach for oligorecurrent MPM. SBRT was well-tolerated even after multiple repetitions and local control was high with a promising median OS

    Transforming Knowledge Orders: Museums, Collections and Exhibitions

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    The history of museums is closely connected not only with the history of collecting and collections, but also with the history of science and humanities. Collections and exhibitions reflect scientific theory and scholarly practice, and in turn shape them. Hence, museums transmit and disseminate, yet also produce knowledge. On the one hand, they visualise and stabilise orders of knowledge through assembling, classifying and fixing objects in exhibitions; on the other hand, new academic paradigms and political changes lead to rearrangements of facts and artefacts in museum storerooms and displays. This volume brings together case studies from various historical and cultural contexts that illuminate such dynamics. Its point of departure is transcultural collections and exhibitions such as cabinets of curiosities and ethnographic collections, whose attempts to inventorise and display the world testify to the desire for, but also the difficulties in establishing and maintaining orders of knowledge. A particular focus is on transformative moments in the history of museums, in particular on the early 1900s, when science and technology museums were established, and on more recent times, which have seen the refurbishment of numerous art and ethnographic museums

    Dose-Volume Histogram Parameters and Quality of Life in Patients with Prostate Cancer Treated with Surgery and High-Dose Volumetric-Intensity-Modulated Arc Therapy to the Prostate Bed.

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    INTRODUCTION Prostate bed radiotherapy (RT) is a major affecter of patients' long-term quality of life (QoL). To ensure the best possible outcome of these patients, dose constraints are key for optimal RT planning and delivery. However, establishing refined dose constraints requires access to patient-level data. Therefore, we aimed to provide such data on the relationship between OAR and gastrointestinal (GI) as well as genitourinary (GU) QoL outcomes of a homogenous patient cohort who received dose-intensified post-operative RT to the prostate bed. Furthermore, we aimed to conduct an exploratory analysis of the resulting data. METHODS Patients who were treated with prostate bed RT between 2010 and 2020 were inquired about their QoL based on the Expanded Prostate Cancer Index Composite (EPIC). Those (n = 99) who received volumetric arc therapy (VMAT) of at least 70 Gy to the prostate bed were included. Dose-volume histogram (DVH) parameters were gathered and correlated with the EPIC scores. RESULTS The median age at the time of prostate bed RT was 68.9 years, and patients were inquired about their QoL in the median 2.3 years after RT. The median pre-RT prostate-specific antigen (PSA) serum level was 0.35 ng/mL. The median duration between surgery and RT was 1.5 years. The median prescribed dose to the prostate bed was 72 Gy. A total of 61.6% received prostate bed RT only. For the bladder, the highest level of statistical correlation (p < 0.01) was seen for V10-20Gy, Dmean and Dmedian with urinary QoL. For bladder wall, the highest level of statistically significant correlation (p < 0.01) was seen for V5-25Gy, Dmean and Dmedian with urinary QoL. Penile bulb V70Gy was statistically significantly correlated with sexual QoL (p < 0.05). A larger rectal volume was significantly correlated with improved bowel QoL (p < 0.05). Sigmoid and urethral DVH parameters as well as the surgical approach were not statistically significantly correlated with QoL. CONCLUSION Specific dose constraints for bladder volumes receiving low doses seem desirable for the further optimization of prostate bed RT. This may be particularly relevant in the context of the aspiration of establishing focal RT of prostate cancer and its local recurrences. Our comprehensive dataset may aid future researchers in achieving these goals
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