RWTH Aachen University Research Articles

“The patient as teacher” - thematic analysis of undergraduate medical students’ experiences with an experiential learning project in palliative care

BackgroundExperiential learning holds high potential for medical students’ education in palliative care. At RWTH Aachen University in Germany, medical students can participate in the course “The Patient as Teacher” offering a one-to-one exchange with a terminally ill patient over a period of several weeks complemented with four supervision sessions and writing of a reflective essay. The course had run from 2005 to 2020 before it was paused due to the Covid-19 pandemic. This study aimed to assess the course’s value as a palliative care teaching tool by investigating students’ motivation and experiences over the years 2005–2020.MethodsA stratified sample of 24 essays was taken from all submitted essays (n = 78), eight essays from the years 2005–2009, 2010–2014, and 2015–2020. Subsequently, a thematic analysis of the selected essays was conducted.ResultsThe students felt motivated by the opportunity to gain more experience in palliative care, to improve their communication skills and to decrease insecurities in interaction with terminally ill patients. They learned about the patient’s biography and medical history, and encountered physical, psychological, social, and spiritual dimensions of living with a life-limiting disease. Moreover, they experienced relationship building and communication with a terminally ill patient outside their role as future doctors. Ultimately, they considered their participation as a beneficial experience on both a personal and professional level.ConclusionsThe course “The Patient as Teacher” presents a valuable tool for experiential learning in palliative care, which has elicited an unceasingly positive response among the students who participated over the years. It has facilitated medical students in overcoming insecurities in dealing with terminally ill patients and supported them in further developing their professional identity.

VR Simulation: Advancing Practical Skills in Computer Science Education

This study presents the successful integration of Virtual Reality (VR) tools as an element in the computer science curriculum at the German University of Technology, Oman. The research study investigates the use of MyScore, a VR application developed by RWTH Aachen University - Teaching & Research Field Engineering Hydrology as an environment for computer hardware assembly and troubleshooting exercises. The VR simulation utilized in this study acts as a gamified environment, incorporating elements like scorekeeping and interactive challenges to enhance practical learning in computer science, akin to game-based strategies that engage and motivate students. Over some weeks, the project involved seven students and one tutor in immersive learning sessions to develop applied skills in computer hardware assembly with VR technology over conventional teaching methods. Structured surveys and direct observations were used for data collection through students' interactions with the VR sessions. We also evaluated the student's learning experiences as well as the usability of technology. The results showed that the user-friendliness of the VR interface and its ability to accurately simulate real-world tasks associated with computer assembly received both positive and negative reactions. While some students praised the technology for being pretty cutting-edge, some criticized it as unrealistic or non-interactive. We also received complaints that ranged from actually moving around in the virtual space to navigating only through teleportation spark points. Specifically, two students got motion sickness, which is a well-known obstacle associated with VR environments, and consequently left the sessions prematurely. The feedback of the instructor pointed out that setting up the VR equipment is straightforward and described some potential methods. Still, a call for more reliability in simulations and better interfaces began to surface as nevertheless less controversial agenda items. However, the instructor saw how VR has the potential to revolutionize educational practices. Providing interactive views between the VR device and students that can act as new learning methods. The present study extends the discussion on educational technology by providing empirical evidence of the benefits and challenges experienced in deploying VR for technical education implementation. These findings thus support the continued development and validation of VR technologies in pursuit of improved commitment, cost-effectiveness, immersion, and environment quality that may maximize learning outcomes in future educational applications.

Serum Adiponectin Is Elevated in Critically Ill Patients with Liver Disease and Associated with Decreased Overall Survival.

Adiponectin, an adipokine with anti-inflammatory properties, has been implicated in various liver diseases. This study aimed to elucidate the prognostic value of serum adiponectin levels in critically ill patients with liver disease. This observational study included 161 critically ill patients admitted to the medical ICU of RWTH Aachen University Hospital due to acute liver failure or decompensated advanced chronic liver disease. Serum adiponectin levels were measured at ICU admission and after 48 h. Clinical parameters and outcomes, including transplant-free survival, were analyzed. Serum adiponectin concentrations were significantly elevated compared to healthy controls (p < 0.001). Levels were particularly high in patients with sepsis compared to those with gastrointestinal bleeding as the precipitating factor of acute decompensation (p = 0.045) and were higher in female patients (p = 0.023). Adiponectin concentrations correlated with the Model of End-Stage Liver Disease (MELD) score and Child-Pugh score. Multivariate analysis confirmed a significant correlation with total bilirubin (r = 0.292, p < 0.001) and serum sodium (r = -0.265, p = 0.028). Higher adiponectin concentrations were associated with a trend towards poorer 30- and 180-day survival. Cox regression analysis identified a significant association between increased adiponectin concentration and reduced transplant-free survival (p = 0.037), supported by a Kaplan-Meier analysis using a cutoff of 119 ng/mL (log-rank 5.145, p = 0.023). Elevated serum adiponectin concentrations are associated with liver dysfunction and poor outcomes in critically ill patients. Higher adiponectin levels at ICU admission may predict poorer transplant-free survival. Further research in larger, multicenter cohorts is warranted to validate these findings and explore the underlying mechanisms.

Teaching Aero-Engine Performance: From Analytics to Hands-On Exercises Using Gas Turbine Performance Software

Abstract In this paper, we present an approach for teaching turbojet engine performance that combines mathematical analysis with the use of performance software to provide students with a comprehensive and in-depth understanding of engine performance and how it is affected by design parameter choices. In the first part, we present the derivation of a universally valid analytical model for turbojet engine cycle design, which is the basis of the propulsion courses at RWTH Aachen University. The analytical model allows for the calculation of specific thrust as well as thermal and propulsive efficiencies as a function of pressure ratios and burner exit temperature. These are all expressed as differentiable functions. Their mathematical extremes form a basis for examining the intricate relationships in turbojet engine design. In the second part, we move from theory to practice. We utilize the GasTurb software, computing turbojet engine cycles for a wide range of cycle design parameters. The analytically derived trends are validated and errors introduced by simplifications are assessed. Differences between the analytical approach and software-based performance simulations of real engines, like temperature-dependent gas properties and secondary air systems, are emphasized and discussed, thus providing a bridge to real-world applications. In summary, this paper describes a two-step approach to teaching turbojet engine design using analytics and performance software. Each approach alone can be used to enrich and extend existing performance courses. Combining the approaches has significant benefits, improving understanding and inspiring students to pursue further research in the field of propulsion.

Development of a lamella‐model to evaluate stresses caused by hot asphalt installation

AbstractOn road‐bridges hot asphalt is installed to provide a level and waterproof surface. That wearing surface, however, needs occasional renewal. On a number of steel highway‐bridges it has been observed that after such asphalt‐renewal fatigue‐cracks have increasingly occurred at the welds of orthotropic bridge‐decks. The German Federal Highway Research Institute has assigned a research project to RWTH Aachen University to evaluate the response of steel‐bridges to time‐ and location‐dependent, nonlinear temperature profiles. Since FEM‐software with the needed level of detailing could not provide solutions for long large‐span bridges, a software‐based lamella‐model was developed. This model enables the partition of the bridge into rectangular beam‐lamella, precisely considers the nonlinear temperature and calculates the inner forces and displacements along the bridge. This paper presents the theoretical background of the lamella‐program as well as results calculated exemplary for a 742m‐long German highway‐bridge including validation with in situ temperature and strain measurements during asphalting.

Anxiety in Endometriosis Patients: Implications for Clinical Practice

AbstractEndometriosis is a chronic disease associated with pain that affects at least 10% of all women of reproductive age. The symptoms of endometriosis have a negative impact on quality of life; they limit the patient physically and psychologically and are the cause of significant anxiety. The aim of our study was to investigate the anxiety levels of women presenting to our specialized endometriosis outpatient clinic at the RWTH Aachen University Hospital. We sought to record their anxiety symptoms and investigate the effect of extensive counseling on anxiety in patients with endometriosis. We hypothesized that detailed counseling and the planning of multimodal endometriosis therapy would reduce anxiety.Data from 183 patients with lower abdominal pain or suspected endometriosis were analyzed. Prior to the examination, the patients completed a standardized anamnesis form including the German version of the STAI (State Trait Anxiety Inventory). The diagnosis of endometriosis was made in accordance with the recent ESHRE guideline and was based on anamnesis, gynecological examination, and ultrasound by a specialist senior physician with many years of experience in treating endometriosis.Prior to the medical examination, we observed a mean STAI-State score of 48.44 ± 11.56 and STAI-Trait score 45.68 ± 11.27. Following medical examination and planning of multimodal therapy, there was a significant decrease in the mean STAI-State score from 48.44 ± 11.56 to 42.43 ± 10.01 (p &lt; 0.0001) and a minimal but significant decrease in the mean STAI-Trait score from 45.68 ± 11.27 to 45.01 ± 11.57 (p &lt; 0.05).Our study showed that endometriosis is associated with high levels of anxiety. Detailed counseling and the planning of a multimodal therapy led to a significant improvement in anxiety levels.

The calcium-sensing-receptor (CaSR) in adipocytes contributes to sex-differences in the susceptibility to high fat diet induced obesity and atherosclerosis

Female mice are more resistant to obesogenic effects of a high-fat diet (HFD), compared to male mice. Although the underlying mechanisms are poorly understood, sex hormones seem to play an important role. Interestingly, the activity of the oestrogen receptor-α (ERα) is affected by the calcium-sensing-receptor (CaSR). Therefore, we investigated sex-differences upon diet-induced obesity and the role of adipocyte-specific CaSR herein. Adipocyte-specific Casr deficient mice (AdipoqCre+Casrflox) and control mice (Casrflox) were injected with AAV8-PCSK9 to make them prone to develop atherosclerosis and fed an obesity-inducing diet for 12 weeks. Female mice have lower visceral white adipose tissue (vWAT) mass compared to male mice, while this sex-difference is abolished upon adipocyte-specific Casr deficiency. Furthermore, while females showed elevated levels of inflammatory cytokines and CD3+CD8+ T cell accumulation in vWAT, compared to males, adipocyte-specific Casr deficiency abrogated this sex-phenotype and demonstrated an inhibition of inflammatory signalling pathways. The expression of Erα, as well as associated genes involved in adipocyte differentiation, was increased in female mice in a mostly adipocyte-specific Casr dependent manner. Interestingly, circulating lipid levels were reduced in female compared to male mice, which correlated with decreased atherosclerotic plaque formation. These systemic effects were abrogated upon adipocyte-specific Casr deficiency. Our findings indicate that female mice show a more pronounced vWAT dysfunction compared to males upon obesity. This sex effect is abolished upon adipocyte-specific Casr deficiency. In contrast, females show diminished atherosclerotic plaque formation compared to males, an effect that was abrogated by adipocyte-specific Casr deficiency. This work was supported by a grant from the Interdisciplinary Center for Clinical Research within the faculty of Medicine at the RWTH Aachen University, by the Corona Foundation, by the Deutsche Forschungsgemeinschaft (DFG), the BMBF and Free State of Bavaria and the DZHK.

Shear and interface shear fatigue of semi‐precast slabs with lattice girders under cyclic loading

AbstractMore and more often, semi‐precast reinforced concrete slabs with lattice girders are employed for industrial buildings or bridges, where they are exposed to high cycle fatigue loading. Despite research in recent years that has led to the formulation of an S–N curve for lattice girders, the effects of cyclic loading on semi‐precast slabs have not yet been sufficiently clarified. Moreover, research has so far been limited to single‐span slabs. The effects of continuous slab systems, which are mainly realized in buildings and bridges, cannot be considered in the calculation of fatigue resistance yet. To improve the fatigue design concept for shear and interface shear, theoretical and experimental investigations were conducted at the Institute of Structural Concrete, RWTH Aachen University. In addition to the fatigue behavior of 16 tests under cyclic loading, particular attention is paid to the increase in shear and interface shear resistance at the inner support of continuous slabs. Furthermore, the influences of the support detailing were investigated. The findings illustrate further potential for optimization of the design under cyclic loading.

Franziska Schoenebeck is the Thieme-IUPAC Prize Winner 2024

Abstract We are delighted to announce that the 2024 Thieme–IUPAC Prize has been awarded to Franziska Schoenebeck of RWTH Aachen University. Professor Schoenebeck becomes the 16th recipient of the prize and joins a distinguished group of scientists whose research has had a major impact on the field of synthetic organic chemistry. The prize, which is awarded every two years and includes an award of € 5000, will be presented to Schoenebeck at the ICOS-24 conference before her Thieme–IUPAC lecture.

Air-liquid interface exposure of A549 human lung cells to characterize the hazard potential of a gaseous bio-hybrid fuel blend.

Gaseous and semi-volatile organic compounds emitted by the transport sector contribute to air pollution and have adverse effects on human health. To reduce harmful effects to the environment as well as to humans, renewable and sustainable bio-hybrid fuels are explored and investigated in the cluster of excellence "The Fuel Science Center" at RWTH Aachen University. However, data on the effects of bio-hybrid fuels on human health is scarce, leaving a data gap regarding their hazard potential. To help close this data gap, this study investigates potential toxic effects of a Ketone-Ester-Alcohol-Alkane (KEAA) fuel blend on A549 human lung cells. Experiments were performed using a commercially available air-liquid interface exposure system which was optimized beforehand. Then, cells were exposed at the air-liquid interface to 50-2000 ppm C3.7 of gaseous KEAA for 1 h. After a 24 h recovery period in the incubator, cells treated with 500 ppm C3.7 KEAA showed significant lower metabolic activity and cells treated with 50, 250, 500 and 1000 ppm C3.7 KEAA showed significant higher cytotoxicity compared to controls. Our data support the international occupational exposure limits of the single KEAA constituents. This finding applies only to the exposure scenario tested in this study and is difficult to extrapolate to the complex in vivo situation.

VSEMERA: pilot project assessing health profession students’ experiences in an international virtual research program

BackgroundThe “Virtual Semester for Medical Research Aachen” (vSEMERA) is an international, interdisciplinary, virtual education program developed for health profession students. The first edition (2021) was hosted by the Medical Faculty of RWTH Aachen University (Germany) in cooperation with Centro Universitário Christus (Brazil) and Universidad Peruana Cayetano Heredia (Peru). The primary aim of the 12-weeks program was to provide students with skills in health science research and prepare them for scientific career paths.MethodsvSEMERA was built on a virtual learning platform, the “vSEMERA-Campus”, designed to foster students’ learning process and social interactions. Maximum flexibility was offered through synchronous and asynchronous teaching, enabling participants to join via any device from any part of the Globe alongside their regular studies. For the program’s first edition (September - November 2021), health profession students from Germany, Brazil, Peru, Spain, and Italy filled all 30 available spots. Satisfaction, quality of the program and courses offered, as well as perceived learning outcomes, were examined using questionnaires throughout and at the end of the program.ResultsThe program received a rating of 4.38 out of 5 stars. While it met most expectations (4.29 out of 5), participants were unable to attend as many courses as intended (2.81 out of 5), mainly due to scheduling conflicts with the home university schedule (46%), internships (23%), and general timing issues (31%). Participants acknowledged considerable improvements in their scientific skills, English language skills, confidence in scientific project management, research career progression, and enthusiasm for a scientific career.ConclusionsvSEMERA represents a promising example of an online international learning and exchange program using pedagogical and technological elements of virtual collaboration and teaching. In addition to advancing future vSEMERA editions, our results may offer insights for similar projects that address the targeted integration of scientific research education into an international, digital learning environment.

Preface to the Proceedings of the 5th European Academic Symposium on EAF Steelmaking

The European Academic Symposium on EAF Steelmaking (EASES) is a series of events targeted at researchers and doctoral candidates working with different aspects of electric arc furnace (EAF) steelmaking. Previously, four events were organised in 2015, 2016, 2018, and 2021 in Aachen, Germany. The 5th European Academic Symposium on EAF Steelmaking (EASES 2023) was organised jointly by the RWTH Aachen University (Department for Industrial Furnaces and Heat Engineering) and University of Oulu (Process Metallurgy Research Unit) and held at the University of Oulu in Oulu, Finland on 5-7 June 2023. A total of 29 presentations were held at the event, out of which 13 featured an accompanying full paper. After the symposium, the authors of the full papers were invited to submit their manuscripts to be included in the proceedings. The proceedings consist of a total of 12 peer-reviewed papers published in the IOP Conference Series: Materials Science and Engineering. Based on the presentations, the development of modelling and monitoring tools for process optimization, the use of biochar to replace fossil carbon for slag foaming, and the use of hydrogen as an alternative burner fuel were identified as current hot topics. In the future, the importance of the EAF process is expected to increase further due to the increasing availability of scrap and plans for ore-based production routes based on hydrogen direct reduction.

Prioritizing bicycle parking improvements: An application of the logsum approach

Increasing the number and quality of bicycle parking facilities is essential to promoting cycling. However, quantifying the benefits of such improvements is difficult and has not yet been the focus of research. Apart from rule-of-half-based approaches, logsum analysis is a method for estimating the consumer surplus of measures, reflecting actual behavior.This paper presents such an analysis of a set of measures on the RWTH Aachen University campus as a case study. Considering only the direct consumer surplus, the economic efficiency of the analyzed measures diverges significantly. The replacement of inadequate front wheel racks has the best consumer surplus-cost ratio, while the construction of bicycle parking stations has the worst. Taking into account modal shift effects and related changes in externalities and reduced demand for car parking, the cost-benefit ratios of the measures would be much higher. Even though the presented logsum approach ignores these second-order effects and focuses exclusively on economic efficiency, it is still useful in practice for prioritizing potential measures. Apart from that, the results show that groups of cyclists benefit differently from certain types of measures depending on their student status, employee group, and the resale value of their bicycle. Additionally, the analysis emphasizes the importance of including informal parking when modeling bicycle parking behavior.

Teleconsultation for Preoperative Anesthesia Evaluation: Identifying Environmental Potentials by Life Cycle Assessment.

Introduction: Teleconsultations for preoperative evaluation in anesthesiology proved to be feasible during the COVID-19 pandemic. However, widespread implementation of teleconsultations has not yet occurred. Besides time savings and economic benefits, teleconsultations in anesthesia may have the potential to reduce CO2 emissions. Methods: We conducted a life cycle assessment based on prospective surveys to assess the potential environmental benefits of preoperative anesthesia teleconsultations in comparison to the status-quo in-person consultations. Within 1 month, all patients presenting at the preoperative anesthesia clinic at RWTH Aachen University Hospital were asked about the distance traveled and mode of transportation to the hospital. The main outcome measure was the potential environmental benefit resulting from the implementation of teleconsultations. Results: In total, 821 out of 981 patients presenting at the anesthesia clinic participated in the survey. Most patients visited on an outpatient basis (62.9%) and traveled by car (81.7%). The median travel distance was 25 km [interquartile range 12-40]. If patients who came to the hospital solely for the anesthesia appointment had scheduled virtual appointments, the emissions of 3.03-ton CO2 equivalents (CO2-eq) could be avoided in the first month after implementation. The environmental impact associated with the production of teleconsultation equipment is outweighed by the reduction in patient travel. If all outpatient appointments were performed virtually, these savings would triple. Within 10 years, more than 1,300 tons CO2-eq could be avoided. Conclusion: Teleconsultations can mitigate the environmental impact of in-person anesthesia consultations. Further research is essential to leverage teleconsultations for preoperative evaluation also across other medical specialties.

Teaching Scientific Integrity in Academia: What and How Students Want to Learn?

AbstractTraining in scientific integrity continues to be an important topic in universities and other research institutions. Its main goal is to prevent scientific misconduct and promote good scientific practice. However, there is still no consensus on how scientific integrity should be taught. Moreover, the perspective of those who receive such training is often underrepresented. Yet it is precisely their interests and needs that must be considered when developing educational programs. Against this backdrop, we conducted a mixed-methods study with the goal of capturing students’ perspectives on the teaching of scientific integrity. Using our online Scientific Integrity course, we explore what specific aspects of digital teaching on scientific integrity are valued, and explore other topics of interest from students’ perspectives on scientific integrity. The article presents (1) students’ self-assessment before (Q1) and after (Q2) taking the online Scientific Integrity course at the RWTH Aachen University in Germany (2) students’ feedback on the course format, video, exam, organization, and support (Q2) (3) a list of other topics of interest in the area of scientific integrity (Q2). The research outcomes demonstrate an improvement in the study participants’ self-assessment after following the online course and there is a general satisfaction among the students in regard to the course digital format and its components although a desire to have more exchange and discussion was expressed. Further topics of interest in the area of scientific integrity that study participants would like to learn about have a practical appeal and among others include research pressure, examples of applications, preventive measures, theory of science, citation rules, funding of university research. Although the results relate to our course, they provide insight into students’ perspectives on online teaching of scientific integrity. Thus, they may be helpful to higher education institutions developing online courses on scientific integrity that are tailored to university students.

Effects of graft detachment on the central corneal thickness after uncomplicated Descemet membrane endothelial keratoplasty

PurposeTo determine if early central corneal thickness (CCT) and best-corrected visual acuity (BCVA) changes indicate graft detachment after uncomplicated Descemet membrane endothelial keratoplasty (DMEK).MethodsIn this analysis of our prospectively collected ADDA registry data (https://drks.de/search/de/trial/DRKS00027180), 45 pseudophakic eyes underwent DMEK surgery at the Department of Ophthalmology, RWTH Aachen University. Anterior segment optical coherence tomography (AS-OCT), the presence of stromal ripples on the posterior corneal surface, and BCVA measurements were assessed prior to, 1 day, 1 week, 1 month, and 6 months after surgery.ResultsEyes were categorized into three groups: no graft detachment (group 1) (20/45; 44.4%), < 1/3 graft detachment (group 2) (14/45; 31.1%), ≥ 1/3 graft detachment followed by rebubbling (group 3) (11/45; 24.4%). Eyes in group 3 had a greater CCT prior to (746.8 ± 95.8 µm vs. 665.0 ± 74.4 µm, P = 0.041), and 1 week (666.8 ± 119.5 µm vs. 556.5 ± 56.8 µm, P = 0.001) after DMEK compared to group 1. By 1 month, CCT in all groups aligned. Comparing prior to and 1 week after DMEK, none of the eyes in group 1 had an increase in CCT, while the CCT increased in 25.0% of eyes in group 2 and 22.2% in group 3. In group 1, 90.0% had a CCT of < 600 µm 1 week after DMEK, compared to only 50.0% in group 2 and 36.4% in group 3. In group 1, 90.0% (18/20) had an improved BCVA 1 week after DMEK, while in groups 2 and 3, 86.7% (12/14) and 18.2% (2/11) improved, respectively. One patient in group 3 showed posterior stromal ripples 1 day and 1 week after DMEK.ConclusionIf 1 week after uncomplicated DMEK CCT is < 600 µm and has decreased from before surgery, BCVA has improved, and there are no posterior stromal ripples, a graft detachment ≥ 1/3 and the need for rebubbling are very unlikely. In all other cases, meticulous slit-lamp and OCT inspection of the peripheral graft for detachments should be advised.

CONSIDERATIONS FOR THE PARAMETERISATION OF A CHATTER DETECTION ALGORITHM

Process instabilites due to the regenerative effect limit the material removal rate of cutting machine tools. A method developed at the Laboratory for Machine Tools and Production Engineering (WZL) at RWTH Aachen University reduces the experimental effort of determining stability limits for milling. The method bears on a time-domain chatter detection algorithm, which detects process instability based on predefined threshold values. Up to now, the definition of the threshold values has been derived from a selective number of sample tests. To investigate the transferability of the chatter detection algorithm to various boundary conditions cutting tests are carried out. In addition, a new stability criterion for high frequency chatter oscillations is introduced. The results are analysed with regard to factors that require an adjustment of the threshold values. Based on the results, a parameterisation of the chatter detection algorithm is presented.

Influence of COVID-19 pandemic on hospitalisations at a paediatric traumatology department during 2020: a single-centre observational study and comprehensive literature review

PurposeThe study investigates changes in the injury characteristics of hospitalised children in a paediatric trauma centre during the COVID-19 pandemic.MethodsData from injured children from the pre-pandemic year 2019 were compared to the pandemic year 2020 using Pearson’s chi-squared test and the Mann–Whitney U test. The period of highly restrictive regulations (HRP) was evaluated separately. A comprehensive literature review with defined search terms resulted in a descriptive data synthesis.ResultsData from 865 patients indicated reductions in admissions of 5.6% and 54.4% during the HRP. In 2020, the hospitalisation time was longer (2.2 ± 2.7 days in 2019 vs. 2.4 ± 2.6 in 2020, p = 0.045); the proportions of wounds requiring surgical therapy (p = 0.008) and of observational treatments, primarily for mild brain injuries (p = 0.046), were higher; and conservative treatments, primarily for contusions, were lower (p = 0.005). There were no significant changes in age, location of lesions, or frequency of surgical therapy; nor were there differences in the HRP, except for fewer injuries in school and kindergarten (p < 0.001). The literature review summarises the main results of 79 studies.ConclusionLimited resources did not alter the indications for surgical therapy. Further studies should examine whether the more common injuries sustained at home were caused by excessive work/childcare demands on parents. Reduced inpatient conservative treatment implies that hospital resources possibly were overused previously. The literature offers answers to many detailed questions regarding childhood injuries during a pandemic and more efficient safe treatment.Registration Ethical committee of RWTH Aachen University EK 22-320; Center for Translational & Clinical Research RWTH Aachen University (CTC-A) 21-430.

Thermal Analysis of Ductile Iron: A New Way to Predict the Mechanical Properties

Thermal analysis is characterized by the recording and evaluation of the temperature curve over time. Due to the correlation between transformation temperatures and chemical composition, thermal analysis is used to determine the carbon and silicon content. Furthermore, the aim is to be able to predict mechanical properties by thermal analysis. However, all current prediction methods refer to the cooling conditions in the investigated casting area and do not allow any transfer to other cooling conditions. There is a lack of a direct and automatic prediction of the mechanical properties from the thermal analysis before casting and transfer to other cooling conditions. For this study, cooling curves from the last 10 years at the Foundry Institute at RWTH Aachen University were evaluated and correlated with the mechanical properties from castings with three different thermal modules. The results of this empirical regression analysis are equations for the investigated mechanical parameters, which can be automatically filled with the characteristic times and temperatures of a thermal analysis in the casting process and the thermal modulus from the casting. For this modulus, the user can insert a corresponding value of the structural casting part that is relevant to the quality requirements in the foundry.

Notice of Violation of IEEE Publication Principles: Sequential Convex Programming for Collaboration of Connected and Automated Vehicles

Notice of Violation of IEEE Publication Principles<BR><BR>"Sequential Convex Programming for Collaboration of Connected and Automated Vehicles," <BR>by Xiaoxue Zhang, Jun Ma, Zilong Cheng, Frank L. Lewis, and Tong Heng Lee, <BR>in IEEE Transactions on Intelligent Vehicles, Early Access <BR><BR>After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE’s Publication Principles. <BR><BR>This paper contains significant portions of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission. <BR><BR>"Networked Model Predictive Control for Vehicle Collision Avoidance" <BR> by Bassam Alrifaee, <BR>in RWTH Aachen University, Dissertation, 04 May 2017 <BR>BR>"Sequential convex programming MPC for dynamic vehicle collision avoidance" <BR>by Bassam Alrifaee, Janis Maczijewski, Dirk Abel, <BR>in the Proceedings of the IEEE Conference on Control Technology and Applications, 2017, pp. 2202-2207 <BR><BR> <br/> This paper investigates the collaboration of multiple connected and automated vehicles (CAVs) in different scenarios. In general, the collaboration of CAVs can be formulated as a nonlinear and nonconvex MPC problem. Most of the existing approaches available for utilization to solve such an optimization problem suffer from the drawback of considerable computational burden, which hinders the practical implementation in real time. This paper proposes the use of SCP, which is a powerful approach to solving the nonlinear and nonconvex MPC problem in real time. To appropriately deploy the methodology, as a first stage, SCP requires linearization and discretization when addressing the nonlinear dynamics of the system model adequately. Based on the linearization and discretization, the original MPC problem can be transformed into a QCQP problem. Besides, SCP also involves convexification to handle the associated nonconvex constraints. Thus, the nonconvex QCQP can be reduced to a quadratic programming (QP) problem that can be solved rather quickly. Therefore, the computational efficiency is suitably improved despite the existence of nonlinear and nonconvex characteristics, whereby the implementation is realized in real time. Furthermore, simulation results in three different scenarios of autonomous driving are presented to validate the effectiveness and efficiency of our proposed approach.