25 research outputs found
Decision making in structural engineering problems under polymorphic uncertainty : a benchmark proposal
The treatment of diverse uncertainties is an important challenge in structural engineering problems, especially from the viewpoint of realistic analysis. Inaccuracy and variability are always present and have to be quantified by either probabilistic, possibilistic, polymorphic or other uncertainty approaches. Regardless to the applied uncertainty quantification method, the numerical predictions have to be useful for structural assessment and decision making. The authors propose in this contribution a benchmark example of a portal frame structure including various uncertainties. The goal of this benchmark study is to compare justifications and decisions provided by different uncertainty models with respect to clear challenges of decision making with and without measurements, data assimilation and design. The engineering problem itself is simple enough to understand and complex enough not to be reduced to a simple formula with uncertain parameters.DFG, 273721697, SPP 1886: Polymorphe Unschärfemodellierungen für den numerischen Entwurf von Strukture
Perioperative and Oncological Outcome of Laparoscopic Resection of Gastrointestinal Stromal Tumour (GIST) of the Stomach
Background. Surgery remains the only curative treatment for gastrointestinal stromal tumour (GIST). Resection needs to ensure tumour-free margins while lymphadenectomy is not required. Thus, partial gastric resection is the treatment of choice for small gastric GISTs. Evidence on whether performing resection laparoscopically compromises outcome is limited. Methods. We compiled patients undergoing laparoscopic resection of suspected gastric GIST between 2003 and 2007. Follow-up was performed to obtain information on tumour recurrence. Results. Laparoscopic resection with free margins was performed in 21/22 patients. Histology confirmed GIST in 17 cases, 4 tumours were benign neoplasms. Median operation time and postoperative stay for GIST patients were 130 (range 80–201) mins and 7 (range 5–95) days. Two patients experienced stapler line leakage necessitating surgical revision. After median follow-up of 18 (range 1–53) months, no recurrence occurred. Conclusions. Laparoscopic resection of gastric GISTs yields good perioperative outcomes. Oncologic outcome needs to be assessed with longer follow-up. For posterior lesions, special precaution is needed. Laparoscopic resection could become standard for circumscribed gastric GISTs if necessary precautions for oncological procedures are observed
Results from a real-time dosimetry study during left atrial ablations performed with ultra-low dose radiation settings
Background: Three-dimensional mapping systems and the use of ultra-low dose radiation protocols have supported minimization of radiation dose during left atrial ablation procedures. By using optimal shielding, scattered radiation reaching the operator can be further reduced. This prospective study was designed to determine the remaining operator radiation exposure during left atrial catheter ablations using real-time dosimetry.
Methods: Radiation dose was recorded using real-time digital dosimetry badges outside the lead apron during 201 consecutive left atrial fibrillation ablation procedures. All procedures were performed using the same X‑ray system (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Germany) programmed with ultra-low dose radiation settings including a low frame rate (two frames per second), maximum copper filtration, and an optimized detector dose. To reduce scattered radiation to the operators, table-suspended lead curtains, ceiling-suspended leaded plastic shields, and radiation-absorbing shields on the patient were positioned in an overlapping configuration.
Results: The 201 procedures included 139 (69%) pulmonary vein isolations (PVI) (20 cryoballoon ablations, 119 radiofrequency ablations, with 35 cases receiving additional ablation of the cavotricuspid isthmus) and 62 (31%) PVI plus further left atrial substrate ablation. Mean radiation dose measured as dose area product for all procedures was 128.09 ± 187.87 cGy ∙ cm2 with a mean fluoroscopy duration of 9.4 ± 8.7 min. Real-time dosimetry showed very low average operator doses of 0.52 ± 0.10 µSv. A subanalysis of 51 (25%) procedures showed that the radiation burden for the operator was highest during pulmonary vein angiography.
Conclusion: The use of ultra-low dose radiation protocols in combination with optimized shielding results in extremely low scattered radiation reaching the operator.Hintergrund: Der Einsatz von dreidimensionalen Mapping-Systemen und von Niedrigdosiseinstellungen der Röntgenanlage führte zu einer Minimierung der Strahlenbelastung bei linksatrialen Ablationen. Optimierte Abschirmung kann die Streustrahlung als Strahlenbelastung des Untersuchers weiter reduzieren. In dieser prospektiven Studie wurde untersucht, welcher Strahlenbelastung der Untersucher unter Anwendung dieser Maßnahmen während linksatrialer Ablationen noch ausgesetzt ist.
Methoden: Die Strahlenbelastung wurde mittels Echtzeitdosimetrie an der Außenseite der Bleischürze während 201 konsekutiven linksatrialen Ablationen gemessen. Alle Prozeduren wurden mit demselben Röntgensystem (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Deutschland) und mit strahlensparenden Einstellungen durchgeführt, unter anderem mit einer niedrigen Bildrate von 2 Bildern/s, maximaler Kupferfilterung und angepasster Detektoreingangsdosis. Um Streustrahlung zu reduzieren, wurden die Seitenlamellen, die mobile Acrylscheibe und die strahlenabsorbierenden Schilde auf dem Patienten überlappend angeordnet.
Ergebnisse: Die 201 Prozeduren umfassten 139 (69%) Pulmonalvenenisolationen (PVI; 20 Kryoballonablationen, 119 Radiofrequenzablationen, in 35 Fällen mit zusätzlicher Ablation des kavotrikuspidalen Isthmus) und 62 (31%) PVI mit zusätzlicher linksatrialer Substratmodifikation. Die Strahlendosis als Dosis-Flächen-Produkt (DAP) betrug durchschnittlich 128,09± 187,87 cGy ⋅cm2 bei einer Fluoroskopiedauer von imMittel 9,4± 8,7min. Die per Echtzeitdosimetrie erhobene mittlere Strahlendosis des Untersuchers zeigte sich mit 0,52± 0,10 μSv als sehr gering. Eine Subanalyse bei 51 (25 %) Prozeduren zeigte, dass die Strahlendosis des Untersuchers während der Pulmonalvenenangiographie am höchsten war.
Schlussfolgerung: Die Kombination von Niedrigdosiseinstellungen und optimierter Abschirmung führt zu einer extremniedrigen Streustrahlung als Strahlenbelastung des Untersuchers
Industrial Segment Anything -- a Case Study in Aircraft Manufacturing, Intralogistics, Maintenance, Repair, and Overhaul
Deploying deep learning-based applications in specialized domains like the
aircraft production industry typically suffers from the training data
availability problem. Only a few datasets represent non-everyday objects,
situations, and tasks. Recent advantages in research around Vision Foundation
Models (VFM) opened a new area of tasks and models with high generalization
capabilities in non-semantic and semantic predictions. As recently demonstrated
by the Segment Anything Project, exploiting VFM's zero-shot capabilities is a
promising direction in tackling the boundaries spanned by data, context, and
sensor variety. Although, investigating its application within specific domains
is subject to ongoing research. This paper contributes here by surveying
applications of the SAM in aircraft production-specific use cases. We include
manufacturing, intralogistics, as well as maintenance, repair, and overhaul
processes, also representing a variety of other neighboring industrial domains.
Besides presenting the various use cases, we further discuss the injection of
domain knowledge
DEGUM, ÖGUM, SGUM and FMF Germany Recommendations for the Implementation of First-Trimester Screening, Detailed Ultrasound, Cell-Free DNA Screening and Diagnostic Procedures
First-trimester screening between 11 + 0 and 13 + 6 weeks with qualified prenatal counseling, detailed ultrasound, biochemical markers and maternal factors has become the basis for decisions about further examinations. It detects numerous structural and genetic anomalies. The inclusion of uterine artery Doppler and PlGF screens for preeclampsia and fetal growth restriction. Low-dose aspirin significantly reduces the prevalence of severe preterm eclampsia. Cut-off values define groups of high, intermediate and low probability. Prenatal counseling uses detection and false-positive rates to work out the individual need profile and the corresponding decision: no further diagnosis/screening - cell-free DNA screening - diagnostic procedure and genetic analysis. In pre-test counseling it must be recognized that the prevalence of trisomy 21, 18 or 13 is low in younger women, as in submicroscopic anomalies in every maternal age. Even with high specificities, the positive predictive values of screening tests for rare anomalies are low. In the general population trisomies and sex chromosome aneuploidies account for approximately 70 % of anomalies recognizable by conventional genetic analysis. Screen positive results of cfDNA tests have to be proven by diagnostic procedure and genetic diagnosis. In cases of inconclusive results a higher rate of genetic anomalies is detected. Procedure-related fetal loss rates after chorionic biopsy and amniocentesis performed by experts are lower than 1 to 2 in 1000. Counseling should include the possible detection of submicroscopic anomalies by comparative genomic hybridization (array-CGH). At present, existing studies about screening for microdeletions and duplications do not provide reliable data to calculate sensitivities, false-positive rates and positive predictive values
Expression of Transketolase like gene 1 (TKTL1) predicts disease-free survival in patients with locally advanced rectal cancer receiving neoadjuvant chemoradiotherapy
<p>Abstract</p> <p>Background</p> <p>For patients with locally advanced rectal cancer (LARC) neoadjuvant chemoradiotherapy is recommended as standard therapy. So far, no predictive or prognostic molecular factors for patients undergoing multimodal treatment are established. Increased angiogenesis and altered tumour metabolism as adaption to hypoxic conditions in cancers play an important role in tumour progression and metastasis. Enhanced expression of Vascular-endothelial-growth-factor-receptor <it>(VEGF-R</it>) and Transketolase-like-1 (<it>TKTL1</it>) are related to hypoxic conditions in tumours. In search for potential prognostic molecular markers we investigated the expression of <it>VEGFR-1</it>, <it>VEGFR-2 </it>and <it>TKTL1 </it>in patients with LARC treated with neoadjuvant chemoradiotherapy and cetuximab.</p> <p>Methods</p> <p>Tumour and corresponding normal tissue from pre-therapeutic biopsies of 33 patients (m: 23, f: 10; median age: 61 years) with LARC treated in phase-I and II trials with neoadjuvant chemoradiotherapy (cetuximab, irinotecan, capecitabine in combination with radiotherapy) were analysed by quantitative PCR.</p> <p>Results</p> <p>Significantly higher expression of <it>VEGFR-1/2 </it>was found in tumour tissue in pre-treatment biopsies as well as in resected specimen after neoadjuvant chemoradiotherapy compared to corresponding normal tissue. High <it>TKTL1 </it>expression significantly correlated with disease free survival. None of the markers had influence on early response parameters such as tumour regression grading. There was no correlation of gene expression between the investigated markers.</p> <p>Conclusion</p> <p>High <it>TKTL-1 </it>expression correlates with poor prognosis in terms of 3 year disease-free survival in patients with LARC treated with intensified neoadjuvant chemoradiotherapy and may therefore serve as a molecular prognostic marker which should be further evaluated in randomised clinical trials.</p
Development of a Stair Climbing Mechanism for a Novel Mechatronic Transport Aid: Preliminary Results
Development of a Stair Climbing Mechanism for a Novel Mechatronic Transport Aid: Preliminary Results
Emergency medical service (EMS) is an essential part of health care with the main task to transport and monitor patients. However, this duty often becomes a challenge due to obstacles - especially stairs - on the way. Associated lifting and carrying of patients regularly imposes high loads in unergonomic working postures on paramedics, leading to the highest work induced injury rates among all industries also due to a deficient usability of existing transport aids. Therefore our goal is the development of a stair climbing mechanism for a novel mechatronic transport aid characterized by high mobility and a small footprint, whereby particular attention has to be paid to application specific requirements. This paper presents the general approach accompanied by results of a functional model from an initial concept study. Acceleration and jerk measurements showed promising results, while most predefined velocities on the model test parkour rise could be reached
ERCP in babies: Low risk of post-ERCP pancreatitis – results from a multicentre survey
Background and aims: Endoscopic retrograde cholangiopancreatography (ERCP) is rarely performed in newborns, and the risk of post-ERCP pancreatitis (PEP) has not been defined in this age group. We therefore performed a European multicentre analysis of PEP rates and risk factors in children aged ≤1 year. Patients and methods: Based on a sample size estimation, 135 consecutive ERCPs in 126 children aged ≤1 year were evaluated from five European centres, and the first ERCP per child analysed. All ERCPs and clinical reports were reviewed manually for PEP and associated risk factors. All ERCPs were performed by endoscopists with high ERCP expertise. Results: No PEP was observed (0/126, 0.0%, CI 0–2.9%) despite the formal presence of multiple risk factors and despite lack of PEP prophylaxis (except one patient having received a pancreatic duct stent). The PEP rate was significantly lower than the PEP rate expected in adults with similar risk factors. Conclusions: ERCP in children aged ≤1 year is safe in terms of PEP. The PEP risk is significantly lower in children aged ≤1 year than in adults, therefore no PEP prophylaxis seems to be needed in young children. Risk factors from adults may not apply to children under 1 year. Reluctance to perform diagnostic ERCP in suspected biliary anomalies should not be based on presumed PEP risk
Endoscopic ultrasound in the pre-therapeutic staging of gastroesophageal adenocarcinoma: the diagnostic value in defining patients eligible for a neoadjuvant chemotherapy regimen
Introduction: Neoadjuvant chemotherapy regimens have been proven to decrease tumour size and stage and significantlyimprove progression-free and overall survival in the treatment of locoregional advanced gastroesophagealadenocarcinomas. Therefore, the pre-therapeutic staging of the tumour extension is of utmost importance for stratificationof patients into this individualized therapy regimen. Within the last years most experience has been gainedusing endoscopic ultrasound (EUS) and it has been considered as a valuable tool for the assessment of locoregionaldisease.Aim: To evaluate the accuracy of endoscopic ultrasound for the preoperative staging of locally advanced gastroesophagealadenocarcinomas with regard to defining patients’ eligibility for neoadjuvant chemotherapy.Material and methods: Between January 2006 and June 2007 consecutive patients (n = 47) who underwent resectionof a gastroesophageal adenocarcinoma and would have been potentially eligible for neoadjuvant chemotherapy wereincluded in this study. Preoperative EUS staging was compared to the postoperative histopathology results. Furthermore,the specificity, sensitivity and positive and negative predictive values for serosal invasion and/or lymph nodepositivity as an eligibility criterion for neoadjuvant chemotherapy were evaluated.Results: Thirty-seven patients were included in the analysis with adenocarcinomas of the distal oesophagus (n = 7),the oesophagogastric junction (n = 8) and the stomach (n = 22). The overall accuracy for predicting the T stage was64.9% (n = 24) with an over- and understaging of 13.5% (n = 5) and 21.6% (n = 8), respectively. The overall accuracyfor predicting the N stage was 64.7% (n = 22), with an over- and understaging of 26.5% (n = 9) and 8.8% (n = 3).Twenty-five out of 37 patients would have met the eligibility criteria for enrolment in a neoadjuvant chemotherapyregimen. The sensitivity was 76% (n = 19/25). The specificity was 75% (n = 9/12). The positive predictive value was86.4%. The negative predictive value was 60%.Conclusions: In this series the sensitivity and specificity of EUS for identification of patients eligible for neoadjuvantchemotherapy seem acceptable. Especially the positive predictive value, which expresses the probability that a patientidentified by EUS as eligible for neoadjuvant chemotherapy met the corresponding histopathological criteria, was high(86.4%). Therefore, it seems justified to apply neoadjuvant chemotherapy in patients identified as eligible by EUS. This underpins the importance of EUS in the staging of gastroesophageal carcinoma. In patients with a “negative” EUS result,the staging needs to be complemented by additional diagnostic modalities such as CT, PET or laparoscopy to facilitatethe correct identification of patients who meet the histopathological inclusion criteria for neoadjuvant chemotherapy