Позиционный электропривод механизма перемещения

Объектом исследования является позиционный асинхронный электропривод механизма горизонтального перемещения груза. Цель работы – исследовать основные характеристики асинхронного электропривода с трехконтурной системой управления положением вала двигателя. В процессе исследования проводились выбор асинхронного двигателя для механизма перемещения, расчет параметров двигателя, его статических и динамических характеристик, выбор преобразователя частоты, синтез трехконтурной системы управления следящим электроприводом на базе регулируемого с векторным управлением.The object of the study is a positional asynchronous electric drive mechanism for the horizontal movement of cargo. The purpose of the work is to investigate the basic characteristics of an asynchronous electric drive with a three-circuit control system for positioning the motor shaft. In the process of research, the choice of an asynchronous motor for the displacement mechanism, calculation of the engine parameters, its static and dynamic characteristics, choice of a frequency converter, synthesis of a three-circuit control system for a servomotor drive based on an adjustable vector control were made

Triploidie als Ursache von Schwangerschaftsgestose im 2. Trimenon

The authors report a case of triploidy in a prematurely born child. The pregnancy was complicated by severe toxemia beginning during the second trimester and terminating in preeclampsia leading to cesarian section in the 33th week of gestation. The externally female child was underweight, hypotonic and asphyctic and died shortly after birth. She exhibited a complex brain malformation including excessive hydrocephaly, cebocephaly and aplasia of the piturary gland, and multiple dysmorphic signs. Autopsy revealed hypoplasia and dysplasia of the adrenal glands; no uterus, tubes and ovaries were present, but no testes were found. The placenta showed localized hydatidiform degeneration and was relatively large. The karyotype was 69,XXY, and with the aid of fluorescence markers, paternal origin of the additional haploid chromosome set was demonstrated. Typical findings in pregnancies with fetal triploidy are discussed and the possibility of prenatal diagnosis of triploidy by chromosome analysis in cultivated amniotic fluid cells is pointed out. Zusammenfassung Ein Fall von kindlicher Triploidie wird vorgestellt. Die Schwangerschaft war gekennzeichnet durch therapieresistente EPH-Gestose im 2. Trimenon mit Übergang in Präeklampsie in der 33. Woche. Der durch Sectio entbundene, nicht lebensfähige Fetus war äußerlich weiblich, untergewichtig, hypoton und asphyktisch. Er wies eine Hirnmißbildung mit Kebozephalie, einem großen univentrikulären Hohlraum und Fehlen der Hypophyse sowie multiple Mißbildungen und dysmorphe Zeichen auf. Bei der Sektion fanden sich Hypo- und Dysplasie der Nebennieren; Uterus, Tuben und Ovarien waren nicht angelegt, Testes waren nicht nachweisbar. Die Plazenta war auffallend groß und zeigte herdförmige hydatidiforme Degenerationen der Zotten. Der Karyotyp war 69,XXY, und mit Hilfe der Fluoreszenzmarker ließ sich der väterliche Ursprung des überzähligen haploiden Satzes nachweisen. Die für Triploidie typischen Schwangerschaftsbefunde werden besprochen und auf die Möglichkeit der pränatalen Diagnose durch Chromosomenuntersuchung an gezüchteten Zellen der Amnionflüssigkeit wird hingewiesen

The INTRABEAM® Photon Radiotherapy System for the adjuvant treatment of early breast cancer: a systematic review and economic evaluation

Background: initial treatment for early breast cancer is usually either breast-conserving surgery (BCS) or mastectomy. After BCS, whole-breast external beam radiotherapy (WB-EBRT) is the standard of care. A potential alternative to post-operative WB-EBRT is intraoperative radiation therapy delivered by the INTRABEAM® Photon Radiotherapy System (Carl Zeiss, Oberkochen, Germany) to the tissue adjacent to the resection cavity at the time of surgery.Objective: to assess the clinical effectiveness and cost-effectiveness of INTRABEAM for the adjuvant treatment of early breast cancer during surgical removal of the tumour.Data sources: electronic bibliographic databases, including MEDLINE, EMBASE and The Cochrane Library, were searched from inception to March 2014 for English-language articles. Bibliographies of articles, systematic reviews, clinical guidelines and the manufacturer’s submission were also searched. The advisory group was contacted to identify additional evidence.Methods: systematic reviews of clinical effectiveness, health-related quality of life and cost-effectiveness were conducted. Two reviewers independently screened titles and abstracts for eligibility. Inclusion criteria were applied to full texts of retrieved papers by one reviewer and checked by a second reviewer. Data extraction and quality assessment were undertaken by one reviewer and checked by a second reviewer, and differences in opinion were resolved through discussion at each stage. Clinical effectiveness studies were included if they were carried out in patients with early operable breast cancer. The intervention was the INTRABEAM system, which was compared with WB-EBRT, and study designs were randomised controlled trials (RCTs). Controlled clinical trials could be considered if data from available RCTs were incomplete (e.g. absence of data on outcomes of interest). A cost–utility decision-analytic model was developed to estimate the costs, benefits and cost-effectiveness of INTRABEAM compared with WB-EBRT for early operable breast cancer.Results: one non-inferiority RCT, TARGeted Intraoperative radioTherapy Alone (TARGIT-A), met the inclusion criteria for the review. The review found that local recurrence was slightly higher following INTRABEAM than WB-EBRT, but the difference did not exceed the 2.5% non-inferiority margin providing INTRABEAM was given at the same time as BCS. Overall survival was similar with both treatments. Statistically significant differences in complications were found for the occurrence of wound seroma requiring more than three aspirations (more frequent in the INTRABEAM group) and for a Radiation Therapy Oncology Group toxicity score of grade 3 or 4 (less frequent in the INTRABEAM group). Cost-effectiveness base-case analysis indicates that INTRABEAM is less expensive but also less effective than WB-EBRT because it is associated with lower total costs but fewer total quality-adjusted life-years gained. However, sensitivity analyses identified four model parameters that can cause a switch in the treatment option that is considered cost-effective.Limitations: the base-case result from the model is subject to uncertainty because the disease progression parameters are largely drawn from the single available RCT. The RCT median follow-up of 2 years 5 months may be inadequate, particularly as the number of participants with local recurrence is low. The model is particularly sensitive to this parameter.Conclusions and implications: a significant investment in INTRABEAM equipment and staff training (clinical and non-clinical) would be required to make this technology available across the NHS. Longer-term follow-up data from the TARGIT-A trial and analysis of registry data are required as results are currently based on a small number of events and economic modelling results are uncertai