22 research outputs found
Application of transfer learning on physics-based models to enhance vessel shaft power predictions
No full textInternational shipping must reduce its emissions to meet global targets, with improving energy efficiency being a crucial step in this journey. Predictive models are essential for implementing energy efficiency measures such as weather routing, scheduling of hull cleanings, and just-in-time arrival, which are vital for reducing fuel consumption and emissions.This paper explores the use of transfer learning to integrate physics-based and data-driven models for predicting vessel shaft power under varying operating conditions. Physics-based models rely on principles of resistance and propulsion, whereas data-driven models employ advanced machine learning techniques utilizing high-frequency operational data. A novel approach is proposed that integrates synthetic data from physics-based simulations with real operational data via transfer learning. This method enhances model accuracy while significantly reducing the amount of data required, and therefore the time until sufficient data is collected to develop a reliable data-driven model.The proposed method is demonstrated on an ocean-going vessel use case to predict the shaft power demand in varying conditions. The results reveal that the proposed transfer learning approach outperforms regular data-driven methods, both in accuracy and required training time. The approach thus offers a robust solution for predicting vessel performance, demonstrating improved model accuracy and reduced dependency on extensive real-world data for training
Lubrication Performance of Engine Commercial Oils with Different Performance Levels: The Effect of Engine Synthetic Oil Aging on Piston Ring Tribology under Real Engine Conditions
No full textTo further improve efficiency in automotive engine systems, it is important to understand the generation of friction in its components. Accurate simulation and modeling of friction in machine components is, amongst other things, dependent on realistic lubricant rheology and lubricant properties, where especially the latter may change as the machine ages. Some results of research under laboratory conditions on the aging of engine commercial oils with different performance levels (mineral SAE 30, synthetic SAE10W-40, and bio-based) are presented in this paper. The key role of the action of pressure and temperature in engine oils’ aging is described. The paper includes the results of experiments over time in laboratory testing of a single cylinder motorbike. The aging of engine oil causes changes to its dynamic viscosity value. The aim of this work is to evaluate changes due to temperature and pressure in viscosity of engine oil over its lifetime and to perform uncertainty analysis of the measured values. The results are presented as the characteristics of viscosity and time in various temperatures and the shear rates/pressures. This paper also includes a Computational Fluid Dynamics (CFD) model, applying the experimental results in the piston ring tribology problem
The role of drama in education in counteracting bullying in schools
No full textBullying is a form of violent behavior that has a markedly negative effect on many aspects of the daily lives of thousands of children. Through a literature review, the present study investigates the term and the nature of bullying, as well as its effect on those involved, and the conditions that prevail in Greek schools. Moreover it contains information about the role of drama in education as a means of counteracting bullying in schools, and the way various experiential drama activities can equip primary school children with the social and emotional skills in order to successfully combat the phenomenon. © 2016 The Author(s)
Modeling of circadian-immune interactions
No full textDysregulation of the inflammatory response is a critical component of many clinically challenging disorders such as sepsis. Inflammation is a biological process designed to lead to healing and recovery, ultimately restoring homeostasis; however, the failure to fully achieve those beneficial results can leave a patient in a dangerous persistent inflammatory state. One of the primary challenges in developing novel therapies in this area is that inflammation is comprised of a complex network of interacting pathways. Here, we discuss our approaches towards addressing this problem through computational systems biology, with a particular focus on how the presence of biological rhythms and importantly circadian (~24hr) and the disruption of these rhythms may be applied in a translational context. By leveraging the information content embedded in physiologic variability, and its loss under acute inflammatory response we aim to gain insight into the underlying physiology. Heart rate variability (HRV) has been studied as a potential prognostic marker in inflammation-linked diseases. We modeled the interactions between human endotoxemia mediators and the autonomic nervous system in order to understand the loss of HRV in presence of stress, allowing for the rationalization of experimental observations in the framework of a quantitative model. Furthermore, by modeling the flow of circadian information from the environmental light/dark cycles to the systemic cortisol level and ultimately to the single immune cell level, we identified critical dynamics that confer robust synchronization and rhythmicity both of which are characteristics associated with well-being. Lastly, by considering the disparate role of cortisol as an immunopermissive and immunosuppressive agent, we elucidated the dynamics leading to a time of day dependence of body’s inflammatory response. These results denote the critical importance of physiological rhythms in homeostasis and stress, and elucidate the potential to derive critical information by the analysis of variability and its source both at the systemic and at the single cell level.Ph.D.Includes bibliographical referencesby Panteleimon D. Mavroudi
Generation of Functional CLL-Specific Cord Blood CTL Using CD40-Ligated CLL APC
No full textPMCID: PMC3526610This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Kallikrein 10 (KLK10) methylation as a novel prognostic biomarker in early breast cancer
No full textBackground: We evaluated the prognostic significance of KLK10 exon 3 methylation in patients with early-stage breast cancer since it has been shown to have a significant impact on biological characteristics of breast tumors. Materials and methods: Using methylation-specific PCR, we evaluated the specificity of KLK10 methylation in 10 breast tumors and matching normal tissues, 10 breast fibroadenomas, 11 normal breast tissues and in a testing group of 35 patients. The prognostic significance of KLK10 methylation was validated in an independent cohort of 93 patients. Results: KLK10 was not methylated in normal breast tissues and fibroadenomas while it was in 5 of 10 breast tumors and in 1 of 10 matching normal tissues. In the testing group of 35 patients, KLK10 methylation was detected in 70.0% of patients who relapsed (P = 0.001) and in 77.8% of patients who died (P = 0.025). In the independent cohort, 53 of 93 (57.0%) patients were found positive for KLK10 methylation. During the follow-up period, 24 of 93 (25.8%) patients relapsed and 19 of 93 (20.4%) died. Disease-free interval (DFI) and overall survival (OS) were significantly associated with KLK10 methylation (P = 0.0025 and P = 0.003). Multivariate analysis revealed that KLK10 methylation was an independent prognostic factor for DFI and OS. Conclusion: KLK10 exon 3 methylation provides important prognostic information in early breast cancer patients. © The Author 2009. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved
Hemostatic activation during cardiopulmonary bypass with different aprotinin dosages in pediatric patients having cardiac operations
No full textExtracardiac Versus Intra-Atrial Lateral Tunnel Fontan: Extracardiac is Better
No full textThis article was prepared to summarize the points made in a debate that the first author (C.L.B.) had with Dr. Richard Jonas at the American Association for Thoracic Surgery 90th Annual Meeting. The topic of the debate was the optimal surgical approach for functional single-ventricle patients: extracardiac versus intra-atrial lateral tunnel Fontan. My role was to take the viewpoint that the extracardiac Fontan is better. This review summarizes our results at Children's Memorial Hospital (Chicago, IL) with 180 patients undergoing a primary Fontan procedure and 126 patients undergoing an extracardiac Fontan as part of a Fontan conversion. The world literature was reviewed on outcomes following the Fontan procedure, focusing on six main areas supporting the superiority of the extracardiac Fontan: hemodynamics, arrhythmias, applicability to complex anatomy, use of cardiopulmonary bypass, complications of fenestration and thromboembolism, and operative mortality. Based on this review, it is our conclusion that the extracardiac Fontan is the procedure of choice for patients with a functional single ventricle based on a very low operative mortality, a lower incidence of early and late arrhythmias, improved hemodynamics, fewer postoperative complications, and applicability to a wide variety of complex cardiac anatomy. © 2011 Elsevier Inc.link_to_subscribed_fulltex
Sex-related cardiovascular prognosis in patients with hypertensive emergencies: a 12-month study
No full textCurrent evidence on the prognosis of patients with a hypertensive crisis and predisposing factors is limited. We registered the clinical phenotype of patients with HC admitted to the emergency department, while those with a hypertensive emergency (HE) were hospitalized. One-year outcomes, i.e., composite of death or cardiovascular hospitalizations, were determined in patients with HE after hospital discharge. Out of 38,589 patients assessed in the emergency department, 256 hypertensive urgencies and 97 HE was registered. After stratification of the HE by sex, 48 men and 46 women completed the one-year follow-up. Men had more events than women (27 vs. 13, Ηazard Ratio 2.2, 95% Confidence Interval 1.03-4.7, p = 0.042) after adjustment for age, cardiovascular or chronic kidney disease, and diabetes mellitus. Our study raises the hypothesis that the male sex is an independent risk factor for cardiovascular outcomes in HE patients. [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to The Japanese Society of Hypertension
A Comparison of Three Methods for the Detection of Circulating Tumor Cells in Patients with Early and Metastatic Breast Cancer
No full textBackground: We directly compared CTC detection rates and prognostic significance, using three different methods in patients with breast cancer (BC). Methods: Early (n=200) and metastatic (n=164) patients were evaluated before initiating adjuvant or first-line chemotherapy, using the CellSearch TM System, an RT-qPCR for CK-19 mRNA detection and by double immunofluorescence (IF) microscopy using A45-B/B3 and CD45 antibodies. Results: Using the CellSearch TM System, 37% and 16.5% of early BC patients were CTC-positive (at ≥1 and ≥2 CTCs/23 ml of blood), 18.0% by RT-qPCR and 16.9% by IF; no agreement was observed between methods. By the CellSearch TM 34.8% and 53.7% (at≥ 5 and ≥ 2 CTCs/7.5 ml) of metastatic patients were CTC-positive, 37.8% by RT-qPCR and 28.5% by IF. A significant agreement existed only between the CellSearch TM and RT-qPCR. In 60.8% of cases, differential EpCAM and CK-19 expression on CTCs by IF could explain the discrepancies between the CellSearch TM and RT-qPCR. CTC-positivity by either method was associated with decreased overall survival in metastatic patients. Conclusion: A significant concordance was observed between the CellSearch TM and RT-qPCR in metastatic but not in early BC. Discordant results could be explained in part by CTC heterogeneity. CTC detection by all methods evaluated had prognostic relevance in metastatic patients. © 2017 The Author(s)
