Combining Structural Optimization and Process Assurance in Implicit Modelling for Casting Parts

The structural optimization of manufacturable casting parts is still a challenging and time-consuming task. Today, topology optimization is followed by a manual reconstruction of the design proposal and a process assurance simulation to endorse the design proposal. Consequently, this process is iteratively repeated until it reaches a satisfying compromise. This article shows a method to combine structural optimization and process assurance results to generate automatically structure- and process-optimized die casting parts using implicit geometry modeling. Therefore, evaluation criteria are developed to evaluate the current design proposal and qualitatively measure the improvement of manufacturability between two iterations. For testing the proposed method, we use a cantilever beam as an example of proof. The combined iterative method is compared to manual designed parts and a direct optimization approach and evaluated for mechanical performance and manufacturability. The combination of topology optimization (TO) and process assurance (PA) results is automated and shows a significant enhancement to the manual reconstruction of the design proposals. Further, the improvement of manufacturability is better or equivalent to previous work in the field while using less computational effort, which emphasizes the need for suitable metamodels to significantly reduce the effort for process assurance and enable much shorter iteration times

Impact of Different Time Interval Bases on the Accuracy of meteorological Data Based Drying Models for Oak (Quercus L.) Logs Stored in Piles for Energy Purposes

Natural drying of fuel wood is a feasible option to increase resource efficiency in biomass based energy supply. Meteorological data based drying models are the state-of-the-art to monitor the drying progress. The continuous weighing approach is used to gain data for developing these models. The aim of this study was to investigate the drying performance of oak (Quercus L.) logs stored in piles for energy purposes and assess the effect of model time interval base on the accuracy of meteorological data based drying models. The log pile’s moisture content dropped from initial 38.9% on February 1, 2013 to 24.8% on October 21, 2013, resulting in a total reduction of 14.1%. At the end, moisture content was distributed evenly within the logs and total dry matter losses were low (2.4%). From load and meteorological data, models were developed including 10-minute, hourly, daily and monthly time interval bases. Model performance was validated by comparing the model estimates to the basic observation. Models proved to be very accurate in estimating moisture content change. Compared to the observation, the hourly time interval based model was the most accurate option (mean deviation of 0.10 ±0.13%), while the least accurate option (10-min interval; 1.49 ±1.29%) was still reasonably accurate. Daily and monthly time interval based models are most suitable for use in the forest industry, as they are accurate, while requiring less extensive and detailed input data than models based on hourly or 10-minute time interval

Interpretation of Thoracic Radiography Shows Large Discrepancies Depending on the Qualification of the Physician—Quantitative Evaluation of Interobserver Agreement in a Representative Emergency Department Scenario

(1) Background: Chest radiography (CXR) is still a key diagnostic component in the emergency department (ED). Correct interpretation is essential since some pathologies require urgent treatment. This study quantifies potential discrepancies in CXR analysis between radiologists and non-radiology physicians in training with ED experience. (2) Methods: Nine differently qualified physicians (three board-certified radiologists [BCR], three radiology residents [RR], and three non-radiology residents involved in ED [NRR]) evaluated a series of 563 posterior-anterior CXR images by quantifying suspicion for four relevant pathologies: pleural effusion, pneumothorax, pneumonia, and pulmonary nodules. Reading results were noted separately for each hemithorax on a Likert scale (0–4; 0: no suspicion of pathology, 4: safe existence of pathology) adding up to a total of 40,536 reported pathology suspicions. Interrater reliability/correlation and Kruskal–Wallis tests were performed for statistical analysis. (3) Results: While interrater reliability was good among radiologists, major discrepancies between radiologists’ and non-radiologists’ reading results could be observed in all pathologies. Highest overall interrater agreement was found for pneumothorax detection and lowest agreement in raising suspicion for malignancy suspicious nodules. Pleural effusion and pneumonia were often suspected with indifferent choices (1–3). In terms of pneumothorax detection, all readers mainly decided for a clear option (0 or 4). Interrater reliability was usually higher when evaluating the right hemithorax (all pathologies except pneumothorax). (4) Conclusions: Quantified CXR interrater reliability analysis displays a general uncertainty and strongly depends on medical training. NRR can benefit from radiology reporting in terms of time efficiency and diagnostic accuracy. CXR evaluation of long-time trained ED specialists has not been tested

Self-sampling versus health care professional-guided swab collection for SARS-CoV-2 testing

Purpose!#!To evaluate the diagnostic reliability and practicability of self-collected oropharyngeal swab samples for the detection of SARS-CoV-2 infection as self-sampling could enable broader testing availability and reduce both personal protective equipment and potential exposure.!##!Methods!#!Hospitalized SARS-CoV-2-infected patients were asked to collect two oropharyngeal swabs (SC-OPS1/2), and an additional oropharyngeal swab was collected by a health care professional (HCP-OPS). SARS-CoV-2 PCR testing for samples from 58 participants was performed, with a 48-h delay in half of the self-collected samples (SC-OPS2). The sensitivity, probability of concordance, and interrater reliability were calculated. Univariate and multivariate analyses were performed to assess predictive factors. Practicability was evaluated through a questionnaire.!##!Results!#!The test sensitivity for HCP-OPS, SC-OPS1, and SC-OPS2 was 88%, 78%, and 77%, respectively. Combining both SC-OPS results increased the estimated sensitivity to 88%. The concordance probability between HCP-OPS and SC-OPS1 was 77.6% and 82.5% between SC-OPS1 and SC-OPS2, respectively. Of the participants, 69% affirmed performing future self-sampling at home, and 34% preferred self-sampling over HCP-guided testing. Participants with both positive HCP-OPS1 and SC-OPS1 indicating no challenges during self-sampling had more differences in viral load levels between HCP-OPS1 and SC-OPS1 than those who indicated challenges. Increasing disease duration and the presence of anti-SARS-CoV-2-IgG correlated with negative test results in self-collected samples of previously confirmed SARS-CoV-2 positive individuals.!##!Conclusion!#!Oropharyngeal self-sampling is an applicable testing approach for SARS-CoV-2 diagnostics. Self-sampling tends to be more effective in early versus late infection and symptom onset, and the collection of two distinct samples is recommended to maintain high test sensitivity

Inter-observer agreement for the histological diagnosis of invasive lobular breast carcinoma.

Invasive lobular breast carcinoma (ILC) is the second most common breast carcinoma (BC) subtype and is mainly driven by loss of E-cadherin expression. Correct classification of BC as ILC is important for patient treatment. This study assessed the degree of agreement among pathologists for the diagnosis of ILC. Two sets of hormone receptor (HR)-positive/HER2-negative BCs were independently reviewed by participating pathologists. In set A (61 cases), participants were provided with hematoxylin/eosin (HE)-stained sections. In set B (62 cases), participants were provided with HE-stained sections and E-cadherin immunohistochemistry (IHC). Tumor characteristics were balanced. Participants classified specimens as non-lobular BC versus mixed BC versus ILC. Pairwise inter-observer agreement and agreement with a pre-defined reference diagnosis were determined with Cohen's kappa statistics. Subtype calls were correlated with molecular features, including CDH1/E-cadherin mutation status. Thirty-five pathologists completed both sets, providing 4,305 subtype calls. Pairwise inter-observer agreement was moderate in set A (median κ = 0.58, interquartile range [IQR]: 0.48-0.66) and substantial in set B (median κ = 0.75, IQR: 0.56-0.86, p < 0.001). Agreement with the reference diagnosis was substantial in set A (median κ = 0.67, IQR: 0.57-0.75) and almost perfect in set B (median κ = 0.86, IQR: 0.73-0.93, p < 0.001). The median frequency of CDH1/E-cadherin mutations in specimens classified as ILC was 65% in set A (IQR: 56-72%) and 73% in set B (IQR: 65-75%, p < 0.001). Cases with variable subtype calls included E-cadherin-positive ILCs harboring CDH1 missense mutations, and E-cadherin-negative ILCs with tubular elements and focal P-cadherin expression. ILCs with trabecular growth pattern were often misclassified as non-lobular BC in set A but not in set B. In conclusion, subtyping of BC as ILC achieves almost perfect agreement with a pre-defined reference standard, if assessment is supported by E-cadherin IHC. CDH1 missense mutations associated with preserved E-cadherin protein expression, E- to P-cadherin switching in ILC with tubular elements, and trabecular ILC were identified as potential sources of discordant classification

Inter-observer agreement for the histological diagnosis of invasive lobular breast carcinoma

Invasive lobular breast carcinoma (ILC) is the second most common breast carcinoma (BC) subtype and is mainly driven by loss of E-cadherin expression. Correct classification of BC as ILC is important for patient treatment. This study assessed the degree of agreement among pathologists for the diagnosis of ILC. Two sets of hormone receptor (HR)-positive/HER2-negative BCs were independently reviewed by participating pathologists. In set A (61 cases), participants were provided with hematoxylin/eosin (HE)-stained sections. In set B (62 cases), participants were provided with HE-stained sections and E-cadherin immunohistochemistry (IHC). Tumor characteristics were balanced. Participants classified specimens as non-lobular BC versus mixed BC versus ILC. Pairwise inter-observer agreement and agreement with a pre-defined reference diagnosis were determined with Cohen's kappa statistics. Subtype calls were correlated with molecular features, including CDH1/E-cadherin mutation status. Thirty-five pathologists completed both sets, providing 4,305 subtype calls. Pairwise inter-observer agreement was moderate in set A (median κ = 0.58, interquartile range [IQR]: 0.48–0.66) and substantial in set B (median κ = 0.75, IQR: 0.56–0.86, p < 0.001). Agreement with the reference diagnosis was substantial in set A (median κ = 0.67, IQR: 0.57–0.75) and almost perfect in set B (median κ = 0.86, IQR: 0.73–0.93, p < 0.001). The median frequency of CDH1/E-cadherin mutations in specimens classified as ILC was 65% in set A (IQR: 56–72%) and 73% in set B (IQR: 65–75%, p < 0.001). Cases with variable subtype calls included E-cadherin-positive ILCs harboring CDH1 missense mutations, and E-cadherin-negative ILCs with tubular elements and focal P-cadherin expression. ILCs with trabecular growth pattern were often misclassified as non-lobular BC in set A but not in set B. In conclusion, subtyping of BC as ILC achieves almost perfect agreement with a pre-defined reference standard, if assessment is supported by E-cadherin IHC. CDH1 missense mutations associated with preserved E-cadherin protein expression, E- to P-cadherin switching in ILC with tubular elements, and trabecular ILC were identified as potential sources of discordant classification