Search

Die Autoren beleuchten hochschulische Bildungsmöglichkeiten mit Massive Open Online Cours (MOOC) von der Erstellung bis zur Durchführung derartiger Kurse. Dabei scheinen die beliebige Wiederholbarkeit von Vorlesungen und die dauernde Abrufbarkeit von Lektionen wesentlich zum Erfolg des Formats beizutragen. (DIPF/Orig.)

Against the background of rising electro mobility concepts for vehicles, corresponding demands on electric machines with regard to their efficiency and power density remarkably influence stator production of such machines in terms of required power output. Here, fundamental parameters that must be considered when designing stators are magnetic properties of the stator core and the electric properties of the winding. Furthermore, the performance of stators is influenced by geometrical properties such as copper filling of the stator grooves and the inner radius of the stator core. In order to increase copper fill factors within the stator body, several stator production technologies have recently been developed and investigated, e.g. hairpin, flyer winding and insertion technology. In addition to those technologies, the so called flatpack bending process constitutes a new process for stator production in which the pre-bent winding is first inserted into a flat, comb like shaped stator core. This assembly is subsequently rounded in a multi-stage rotary draw bending process, obtaining high copper filling ratios. However, the main challenge for this bending and subsequent springback procedure arises from the roundness deviations occurring along current process chains. For this reason, a simulation model has been created in the framework of a collaborative research project between SEG Automotive and the Institute for Metal Forming Technology, Stuttgart, aiming to better understand and to improve this stator flatpack bending process. For an extensive validation of this model, various parameters need to be examined and their influence to be evaluated. In this study, simulations were performed using this numerical model, in which levels of yield strength of the material to be formed were varied in order to calculate their influences on the outer radius. For validation objectives of simulation results, bending experiments were subsequently conducted, so samples obtained were evaluated using 3D scan technology. As a result, only a maximum difference of 0.3 mm of bent stator core was observed by comparing the numerically calculated results and the results measured during the experiments.

The automotive industry is currently experiencing an unprecedented amount of innovation and introducing new technologies in almost every field. Even with all of these exciting new developments, one of the most important points is to maintain or improve the reliability and lifetime of cars. In response to these demands, automotive manufacturers and suppliers have worked to strengthen their expertise in this area.

Purpose To determine the efficacy and feasibility of induction chemotherapy (ICT) with docetaxel, cisplatin and 5-fluorouracil followed by radiotherapy and cetuximab (C) in patients with locally advanced head and neck cancer. Patients and methods Forty-nine previously untreated patients with local advanced stage III and IV squamous cell carcinoma of the head and neck (SCCHN) received three courses of ICT consisting of docetaxel 75 mg/m2 day 1, cisplatin 75 mg/m2 day 1 and infusional 5-fluorouracil 750 mg/m2/day on days 1–5 followed by radiotherapy plus C at 250 mg/m2/week (after an initial loading dose of 400 mg/m2). Results After completion of ICT 44 of 49 patients received radiotherapy plus C. Three months after therapy completion tumour response was observed in 33 patients and after two years, 25 patients were in complete remission (CR). The most common grade 4 toxicity during the whole treatment period was dermatitis (30%), followed by mucositis (27%) and neutropenia (17%) without fever. One toxic related death was observed during ICT. Two-year progression-free survival (PFS) rate was 59% and two-year overall survival (OS) rate was 63%, respectively. Conclusion Concurrent radiotherapy plus C after three courses of ICT was feasible and was associated with promising CR, PFS and OS rates. Further optimisation of dose and sequence is warranted.

The e-book market is currently in a strong upswing. This research study deals with the question which practical uses the e-book format EPUB3 offers for (higher) education. By means of a didactic content analysis, a range of interactive exercise types were developed as a result of conversations with teachers. For this purpose, a didactic and technical concept has been developed. Different kinds of exercises were prototypically implemented in an e-book. Finally, a brief overview reflects the present state of the current e-book readers. A subsequent discussion illuminates the strengths and weaknesses of the format. In summary, it can be remarked that EPUB3 is suitable for a variety of different exercises and that it is able to serve as a basic format for forthcoming digital textbooks. Furthermore the openness of EPUB3 will assist Open Learning and Teaching in a meaningful way., Comment: Conference, 13 pages

The standard treatment for early breast cancer comprises wide local excision, sentinel lymph node biopsy or axillary lymph node dissection, adjuvant medical treatment and radiotherapy to the whole breast. Many studies suggest that local control plays a crucial role in overall survival. The local recurrence rate is estimated to be 1% per year and varies between 4 and 7% after 5 years and up to 10 to 20% in the long-term follow up. On the basis of low local recurrence rates the concept of whole breast irradiation comes up for discussion, and partial breast irradiation (PBI) is increasingly under consideration. Intraoperative radiotherapy (IORT) is referred to as the delivery of a single high dose of irradiation directly to the tumor bed (confined target) during surgery. PBI (limited field radiation therapy, accelerated partial breast irradiation APBI) is the irradiation exclusively confined to a breast volume, the tumor surrounding tissue (tumor bed) either during surgery or after surgery without whole breast irradiation. Various methods and techniques for IORT or PBI are under investigation. The advantage of a very short radiation time or the integration of the complete radiation treatment into the surgical procedure convinces at a first glance. The promising short-term results of those studies must not fail to mention that local recurrence rates could probably increase and furthermore give rise to distant metastases and a reduction in overall survival. The combination of IORT in boost modality and whole breast irradiation has the ability to reduce local recurrence rates. The EBCTCG overview approves that differences in local treatment that substantially affect local recurrence rates would avoid about one breast cancer death over the next 15 years for every four local recurrences avoided, and should reduce 15-year overall mortality.

Purpose Neointimal hyperplasia is one of the limiting factors in infrainguinal prosthetic vascular grafting. We conducted a pilot study to assess the possible role of radiotherapy for the prevention of this proliferating cellular process. Methods and materials Ten patients (7 men, 3 women; median age: 73 years) suffering from critical leg ischemia were treated by infrainguinal revascularization using 6-mm polytetrafluoroethylene. Postoperative radiation therapy of the anastomotic sites started within 24 h. A dose of 20.4 Gy was delivered in 12 fractions in 2.5 weeks by external beam radiation with electrons. The target volume was defined as the clip-marked anastomotic region plus a 1.5-cm safety margin in each direction. Results Radiation therapy was technically feasible in all cases without radiation-related side effects. In one patient, radiotherapy had to be terminated prematurely, because of a hematoma at the distal anastomotic site with consequent skin necrosis. One patient developed an occlusion of a suprainguinal graft without anastomotic stenosis after 9 months; 2 other grafts occluded at 12-month intervals. At a median follow-up of 16 months, the remaining 6 patients had no signs of restenosis. Conclusions The restenosis rate of peripheral vascular grafts after external beam radiation was lower than expected without additional treatment. The value of this approach will now be determined in a randomized prospective trial.

Purpose: To examine the need for completion angiography after endovascular femoropopliteal brachytherapy using a centering catheter. Methods: Nine consecutive patients (7 men; mean age 68 years, range 53–79) were enrolled in a double-blinded multicenter randomized trial of endovascular brachytherapy after femoropopliteal balloon angioplasty. All patients underwent postdilation angiography, after which the centering catheter was placed in the dilated segment. The patients were randomized and transferred to the radiotherapy unit; the centering catheter was inflated only in patients randomized to receive brachytherapy (18 Gy of γ radiation delivered to the target site 2 mm from an iridium-192 source axis). Because the local ethics committee required angiography after any interventional procedure (not stipulated in the study protocol), our patients were taken back to the angiosuite for angiography. Results: There were no complications of angioplasty or centering catheter introduction. In the 5 patients randomized to brachytherapy, the median inflation time of the centering catheter was 12.1 minutes (range 9.1–13.3). The completion angiogram following brachytherapy showed peripheral embolization in 2 patients and lesion recoil that required redilation in another; all the complications were confined to the treatment group. Conclusions: Three of 5 patients who received brachytherapy via a centering catheter demonstrated sequelae on postradiation angiography. Therefore, as in any other peripheral vascular intervention, completion angiography after brachytherapy seems to be essential in preventing delayed diagnosis of procedural complications.

Blended learning became the most popular educational model that universities apply for teaching and learning. This model combines online and face-to-face learning environments, in order to enhance learning with implementation of new web technologies and tools in learning process. In this paper principles of DeLone and Mclean success model for information system are applied to Kano two-dimensional model, for categorizing quality attributes related to satisfaction of students with web based learning system used in blended learning model. Survey results are obtained among the students at “Mediterranean” University in Montenegro. The (dys)functional dimensions of Kano model, including Kano basic matrix for assessment of the degree of students’ satisfaction level, have been considered in some more detail through corresponding numerical, graphical, and statistical analysis.

This paper considers beginning steps in introducing e-learning into seafarers’ education, as additional mode of acquiring knowledge at the Faculty of Maritime Studies which is a part of the University of Montenegro. Related activities are the result of the enthusiasm of few professors and they are partly supported by a small, initial project of bilateral scientific and technological cooperation between Austria and Montenegro. The paper is conceived in a way that it considers following issues: (a) a brief discussion of some current shortages in maritime education and training in general; (b) possibilities of getting advantages through introducing e-learning into this respectable field of education; (c) some advantages and disadvantages of Moodle which has been used as a technological platform for introducing e-learning in the analyzed case; (d) results of the surveys conducted among involved students, teachers, and professionals in the field of employing new media techniques into the knowledge transfer, and (e) some conclusion remarks regarding possibilities of optimal combining maritime and virtual education.

Increasing functional requirements and system complexity on the one hand and decreasing time for development as well as cost reduction on the other hand are some of the challenging constraints that nearly all manufacturers face today. Additionally, customers expect high quality products. The present paper illustrates the current situation in reliability-oriented development of complex and intelligent mechatronic systems. Therefore, typical development and reliability processes are depicted. It is obvious, that in the current situation, a sustainable and effective reliability-oriented development in Mechatronics is not assured. Analyzing this position in detail, the lack of reliability-relevant information, their availability and especially the insufficient information flow are the serious factors. They avoid a considerable increase of reliability when applying Mechatronics. Therefore, the current reliability information flow in development as well as challenges for a sustainable use of reliability-related information are regarded in detail. An integrated use and re-use of reliability-related information throughout the development process of complex mechatronic systems enables a considerable reduction of effort combined with enhancing systems' reliability. Finally the idea of a theoretical reliability information model is pointed out.

In this study, a new method is introduced, which allows the overlay of three-dimensional structures, that have been delineated on transverse slices, onto the fluoroscopy from conventional simulators in real time. Setup deviations between volumetric imaging and simulation were visualized, measured and corrected for 701 patient isocenters. Comparing the accuracy to mere virtual simulation lacking additional X-ray imaging, a clear benefit of the new method could be shown. On average, virtual prostate simulations had to be corrected by 0.48 cm (standard deviation [SD] 0.38), and those of the breast by 0.67 cm (SD 0.66). The presented method provides an easy way to determine entity-specific safety margins related to patient setup errors upon registration of bony anatomy (prostate 0.9 cm for 90% of cases, breast 1.3 cm). The important role of planar X-ray imaging was clearly demonstrated. The innovation can also be applied to adaptive image-guided radiotherapy (IGRT) protocols.

For intraoperative radiotherapy (IORT) during breast-conserving treatment four different techniques have been addressed: interstitial brachytherapy, an inflatable balloon with a central high-dose-rate source (MammoSite), a miniature orthovolt system (Intrabeam), and linac-based electron radiotherapy (IOERT). The dosimetric properties of these methods are compared. Planning target volumes (PTVs) of the same size but of different shapes are assumed, corresponding to the technique’s specific situs. Dose distributions for the PTVs and for surrounding tissues are demonstrated by dose-volume histograms and a list of physical parameters. A dose inhomogeneity index (DII) is introduced to describe the deviation of a delivered from the prescribed dose, reaching its minimal value 0 in case of perfect homogeneity. In terms of DII, IOERT reaches the lowest value followed by the MammoSite, the Intrabeam and interstitial implants. The surrounding tissues receive the smallest average dose with IOERT, closely followed by the orthovolt system. When comparing simplified geometric figures, IOERT delivers the most homogeneous dose distributions. However, in clinical reality PTVs often present asymmetric shapes instead of ideal geometries. Due to a strictly centric dose fall-off, any system with a round central applicator will have technical limits. During IOERT margin-directed applicator guidance is possible and interstitial brachytherapy allows for polygonal dose shaping. These techniques seem to be superior for asymmetric PTV irradiation.

Aim of this study is to show that ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery can be reduced by proper surgery and modern radiotherapy techniques. Three hundred and seventy eight women with stage I or II breast cancer had breast conserving surgery and received 51–56.1 Gy of postoperative radiation to the whole breast in 1.7 Gy fractions, but patients received different boost strategies. Group 1 (n = 188) received electron boost radiation of 12 Gy subsequent to the irradiation to the whole breast, group 2 (n = 190) received intraoperative electron boost radiation of 9 Gy directly to the tumor bed, followed by whole breast irradiation. After a median follow up period of 81.0 months in group 1 and a median follow up period of 51.1 months in group 2, 12 IBTRs (6.4%) could be observed in group 1 and no IBTR could be observed in group 2 (0.0%). The 5-year actuarial rates of IBTR were 4.3% (95% CI, 1.9–8.3%) and 0.0% (95% CI, 0.0–1.9%), respectively (p = 0.0018). The 5-year actuarial rates of distant recurrence were 8.6% (95% CI, 4.9–13.5%) and 4.2% (95% CI, 1.8–8.2%), respectively (p = 0.08). The 5 year disease-free survival rates were 90.9% (95% CI, 85.8–94.7%) in group 1 and 95.8% (95% CI, 91.8–98.2%) in group 2 (p = 0.064). Immediate IORT-boost and whole breast irradiation yields excellent local control at 5 years, and was associated with a statistically significant decreased rate of IBTR compared with a similar cohort of patients treated with whole breast irradiation and conventional electron boost. © 2005 Wiley-Liss, Inc.

Background and Purpose: The purpose of this sequential intervention study was to determine the rate of local recurrences and the rate of distant metastases in patients with invasive breast cancer who had been treated with breast-conserving surgery and postoperative radiation therapy to the whole breast either with postoperative electron boost in group 1 or with intraoperative electron boost (IORT) in group 2. Patients and Methods: After breast-conserving surgery, 378 women with invasive breast cancer of tumor sizes T1 and T2 received 51‐56.1 Gy of postoperative radiation therapy to the whole breast in 1.7-Gy fractions. 188 of those patients additionally received a postoperative electron boost of 12 Gy in group 1 from January 1996 to October 1998. Consecutively, from October 1998 to March 2001, 190 patients received intraoperative electron-boost radiotherapy of 9 Gy to the tumor bed in group 2. The groups were comparable with regard to age, menopausal status, tumor size, grading, and nodal status. All statistical tests were twosided. Results: During a median follow-up period of 55.3 months in group 1 and 25.8 months in group 2, local recurrences were observed in eight of 188 patients (4.3%) in group 1, and no local recurrence was seen in group 2 (p = 0.082). Distant metastases occurred in 15 of the 188 patients (7.9%) in group 1 and in two of the 190 patients (1.1%) in group 2 (p = 0.09). The 4-year actuarial rates of local recurrence were 4.3% (95% confidence interval, 1.8‐8.2%) and 0.0% (95% confidence interval, 0.0‐1.9%) and the 4-year actuarial rates of distant metastases were 7.9% (95% confidence interval, 4.5‐12.8%) and 1.1% (95% confidence interval, 0.1‐3.8%). Conclusion: Immediate IORT boost yielded excellent local control figures in this prospective investigation and appears to be superior to conventional postoperative boost in a short-term follow-up.

Jayant Vaidya and colleagues (July 10, p 91) suggest that a single dose of targeted intraoperative radiotherapy (TARGIT) should be considered as an alternative to external-beam radiotherapy delivered over several weeks for selected patients with breast cancer. We consider the results of this trial preliminary and immature since the follow-up is much too short to draw any conclusions about local recurrence rates. The fi nding in this trial that most local recurrences occur in years 2 and 3 do not imply that local recurrences after this time will not occur. When using an orthovoltage technique with a very low-dose penetration to a depth of 1 cm, the rate of in-breast recurrences has to be observed extremely carefully in the long term. The median time to true local recurrences is somewhere between 40 months and 65 months, and out-quadrant relapses occur later than that. Furthermore, the Kaplan-Meier plots in fi gure 4 show that, of 2232 patients at risk, only 420 (19%) completed 4-year follow-up (212 in the TARGIT group). Of these 212 patients, only 86% received intra operative radio therapy alone, meaning that about 14% received external-beam radiotherapy as well. 65% of patients also received endocrine treatment, which is known to be associated with a signifi cant decrease or at least delay in the rate of local recurrences, which become apparent after more than 5 years’ follow-up. Another area of concern is the postpathology stratum: 672 patients had a postpathology entry to the trial, meaning that about 336 patients allocated to TARGIT (most of the Danish and the Australian patients) were referred for a second surgical procedure. In those cases, targeted intraoperative radiotherapy was not an intraoperative treatment in the classic sense—a second surgical procedure had to be done for no reason other than the application of the radiation therapy. Overall, we advise against the use of targeted intraoperative radiotherapy as a single shot outside a clinical trial until the long-term follow-up data for non-inferiority are available.