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A rapid defossilisation of the industry sector is required to stop further greenhouse gas emissions and to curb global warming. Additionally, to avoid irreversible consequences caused by climate change, the deployment of negative emission technologies is required to reduce the carbon dioxide (CO2) concentration in Earth’s atmosphere to a sustainable level. A novel approach to store gaseous CO2 from direct air capture facilities in solid silicon carbide (SiC) is presented. A chain of established processes to produce SiC from renewable electricity and air is evaluated in terms of energy and mass balances. Furthermore, possible fields of SiC utilisation are considered. Electricity-based SiC (e-SiC) can serve the growing global market for technical ceramics and can possibly be used to tackle increasing construction sand shortages in the construction industry by partially substituting sand. Calculations of the levelised cost of carbon dioxide removal show that storing ambient CO2 in solid SiC that can be subsequently sold on the world market can eventually create profit. In 2050, a net benefit of 259 €/tCO2 or 631 €/tSiC can be realised if the SiC product is sold at the world market with additional carbon compensation. Therefore, the proposed SiC production chain might be able to challenge conventionally produced SiC, while empowering negative emissions. In 2050, the net CO2 emission potential is limited to about 290 MtCO2/a for technical ceramics, but may reach up to 13.6 GtCO2/a for construction sand. Results show that e-SiC production is economically feasible for technical ceramics but not for construction sand without further process cost decrease. Alternative processes to produce e-SiC are described and evaluated. Future research opportunities are discussed.
Theoretical considerations on 2D multistable tensegrity structures based on equilateral triangles
(2025)
This paper investigates the stability and stiffness characteristics of two-dimensional tensegrity structures based on two equilateral triangles connected by tensioned members, resulting in three multistable structural variants. The stability analysis is conducted by examining the system’s potential energy. Using a form-finding algorithm, the study reveals how the stiffness of tensioned members impacts global compliance distribution and the transition between equilibrium positions. By adjusting the stiffness of individual members and varying force application points, significant modifications in the overall stiffness of the structure can occur. The study shows that increasing the force amplitude can lead to equilibrium position changes, particularly in asymmetrical structures. These findings provide valuable insights for designing adaptable, stiffness-tunable structures. The results emphasize the critical role of force direction, stiffness distribution, and transitions between stable equilibrium states in the development of advanced mechanical systems.
This paper investigates the influence of the roller geometry and the manufacturing tolerances on the wear behavior of a short and wide flat-belt conveyor with three rollers, using the frictional power density as a qualitative wear indicator. Previous studies mainly focus on overall belt dynamics and wear with ideal cylindrical rollers. This work emphasizes the effect of geometric deviations arising from manufacturing or intentional shaping. Building upon an existing lumped mass model of the belt and a visualization approach of the frictional power density, the model is extended by a deflection-based roller geometry that enables the analysis of concave and convex roller profiles. The study reveals that small deviations from an ideal cylindrical roller significantly influence the distribution of frictional power density across the belt width. Convex roller geometries particularly increase edge wear, while concave rollers reduce it up to a certain point before it rises again. For the investigated three-roller system, the authors therefore propose a slightly concave roller geometry with a narrow tolerance band as a pragmatic trade-off between reduced frictional power density and belt-run stability, the latter being a known effect of concave roller geometries. These insights enhance the understanding of how geometric tolerances affect belt deformation and wear behavior. They establish a consistent framework for deriving design guidelines and conducting future parameter studies involving belt tension, speed, and alternative roller geometries.
Purpose The Hospital Frailty Risk Score (HFRS) is derived from routinely collected data and validated as a geriatric risk stratification tool. This study aimed to evaluate the utility of the HFRS as a predictor for postoperative adverse events in spine surgery. Methods In this retrospective analysis of 2042 patients undergoing spine surgery at a university spine center between 2011 and 2019, HFRS was calculated for each patient. Multivariable logistic regression models were used to assess the relationship between the HFRS and postoperative adverse events. Adverse events were compared between patients with high or low frailty risk. Results Patients with intermediate or high frailty risk showed a higher rate of reoperation (19.7% vs. 12.2%, p < 0.01), surgical site infection (3.4% vs. 0.4%, p < 0.001), internal complications (4.1% vs. 1.1%, p < 0.01), Clavien-Dindo IV complications (8.8% vs. 3.4%, p < 0.001) and transfusion (10.9% vs. 1.5%, p < 0.001). Multivariable logistic regression analyses revealed a high HFRS as independent risk factor for reoperation [odds ratio (OR) = 1.1; 95% confidence interval (CI) 1.0-1.2], transfusion (OR = 1.3; 95% CI 1.2-1.4), internal complications (OR = 1.2; 95% CI 1.1-1.3), surgical site infections (OR = 1.3; 95% CI 1.2-1.5) and other complications (OR = 1.3; 95% CI 1.2-1.4). Conclusion The HFRS can predict adverse events and is an easy instrument, fed from routine hospital data. By identifying risk patients at an early stage, the individual patient risk could be minimized, which leads to less complications and lower costs.
The aim of this study is to show the concordance of an app-based decision support system and the diagnosis given by spinal surgeons in cases of back pain. 86 patients took part within 2 months. They were seen by spine surgeons in the daily routine and then completed an app-based questionnaire that also led to a diagnosis independently. The results showed a Cramer's V = .711 (p < .001), which can be taken as a strong relation between the tool and the diagnosis of the medical doctor. Besides, in 67.4% of the cases, the diagnosis was concordant. An overestimation of the severity of the diagnosis occurred more often than underestimation (15.1% vs. 7%). The app-based tool is a safe tool to support healthcare professionals in back pain diagnosis.
Introduction
Numbers of total hip arthroplasty (THA) are steadily rising and patients expect faster mobility without pain postoperatively. The aim of enhanced recovery after Surgery (ERAS) programs in a multidisciplinary setup was to keep pace with the needs of quality and quantity of surgical THA-interventions and patients? expectations.
Methods
194 patients undergoing THA procedures were investigated after single-blinded randomization to ERAS (98) or conventional setup group (96). Primary outcome variable was mobilization measured with the Timed Up and Go Test (TUG) in seconds. Secondary outcome variables were floor count and walking distance in meters as well as rest, mobilization and night pain on a numerous rating scale (NRS). All variables were recorded preoperatively and daily until the sixth postoperative day. To assess and compare clinical outcome and patient satisfaction, the PPP33-Score and PROMs were used.
Results
No complications such as thromboembolic complications, fractures or revisions were recorded within the first week postoperatively in either study group. Compared to the conventional group, the ERAS group showed significantly better TUG (p?<?0.050) and walking distance results after surgery up to the sixth, and floor count up to the third postoperative day. On the first and second postoperative day, ERAS patients showed superior results (p?<?0.001) in all independent activity subitems. Regarding the evaluation of pain (NRS), PPP33 and PROMS, no significant difference was shown (p?>?0.050).
Conclusion
This prospective single-blinded randomized controlled clinical trial was able to demonstrate excellent outcome with comparable pain after ERAS THA versus a conventional setup. Therefore, ERAS could be used in daily clinical practice.
Fast-Track-Endoprothetik
(2024)
Einführung
Wesentliche Bestandteile von Fast-Track- oder Enhanced-Recovery-Programmen in der Endoprothetik sind die Optimierung der interdisziplinär-organisatorischen Abläufe sowie der prä-, intra- und postoperativen Vorgehensweisen im klinischen Alltag. Die frühpostoperative Mobilisation der Patienten ist nach Gelenkersatzoperation von zentraler Bedeutung, mit dem Ziel, Schmerzen und Komplikationen nachweislich zu vermeiden. Dieser Beitrag gibt einen detaillierten Überblick hinsichtlich der zwischenzeitlich zunehmend verbreiteten Fast-Track-Vorgehensweisen. Zudem zeigt er die klinischen Vorteile von Fast-Track für die Hüftendoprothetik im Rahmen eines randomisierten Studiendesigns evidenzbasiert auf.
Material und Methoden
Es wurden 194 Patienten mit primärer HTEP nach einfach verblindeter Randomisierung in zwei Gruppen untersucht: Fast-Track (n?=?98) oder konventioneller Behandlungspfad (n?=?96). Als primärer Outcomeparameter war die Mobilisierung definiert, gemessen mit dem Timed-Up-and-Go-Test (TUG) in Sekunden. Sekundäre Parameter waren erreichbare Gehstrecke in Metern sowie Schmerzen auf der Numerische Rating-Skala (NRS). Alle Parameter wurden präoperativ und täglich bis zum 6. postoperativen Tag erfasst.
Ergebnisse
Innerhalb der ersten postoperativen Woche wurden keine Komplikationen oder Revisionen verzeichnet. Die Fast-Track-Gruppe zeigte im Vergleich zur konventionellen Gruppe bis zum 6. postoperativen Tag signifikant bessere TUG-Werte sowie Gehstreckenergebnisse (jeweils p?<?0,05). Bezüglich der Bewertung von Schmerzen (NRS) zeigte sich kein signifikanter Unterschied (p?>?0,05).
Fazit
Die Anwendung von Fast-Track-Konzepten in der Hüftendoprothetik kann evidenzbasiert die klinischen Ergebnisse verbessern. Diese prospektive, einfach verblindete randomisierte kontrollierte Studie konnte ein sehr gutes kurzfristiges Ergebnis mit vergleichbaren Schmerzen nach Fast-Track-HTEP im Vergleich zu einem konventionellen Behandlungspfad aufzeigen. Fast-Track-Konzepte sind hochwirksam in Bezug auf Frühmobilisierung und klinisches Ergebnis ? ohne in der Frühphase ein höheres Komplikationsrisiko einzugehen.
IntroductionEnhanced recovery after surgery (ERAS) leads to less morbidity, faster recovery, and, therefore, shorter hospital stays. The expected increment of primary total hip arthroplasty (THA) in the U.S. highlights the need for sufficient pain management. The favorable use of short-lasting spinal anesthesia enables early mobilization but may lead to increased opioid consumption the first 24 h (h) postoperatively.MethodsIn a retrospective study design, we compared conventional THA with postoperative immobilization for two days (non-ERAS) and enhanced recovery THA with early mobilization (ERAS group). Data assessment took place as part of the "Quality Improvement in Postoperative Pain Treatment project" (QUIPS). Initially, 2161 patients were enrolled, resulting in 630 after performing a matched pair analysis for sex, age, ASA score (American-Society-of-Anesthesiology) and preoperative pain score. Patient-reported pain scores, objectified by a numerical rating scale (NRS), opioid consumption and side effects were evaluated 24 h postoperatively.ResultsThe ERAS group revealed higher activity-related pain (p = 0.002), accompanied by significantly higher opioid consumption (p < 0.001). Maximum and minimum pain as well as side effects did not show significant differences (p > 0.05).ConclusionThis study is the first to analyze pain scores, opioid consumption, and side effects in a matched pair analyses at this early stage and supports the implementation of an ERAS concept for THA. Taking into consideration the early postoperative mobilization, we were not able to detect a difference regarding postoperative pain. Although opioid consumption appeared to be higher in ERAS group, occurrence of side effects ranged among comparable percentages.
Hintergrund
Sedentäres Verhalten ist mit einem erhöhten Risiko für chronische Krankheiten und einer höheren Gesamtmortalität assoziiert. Arbeitsbezogenes Sitzen hat einen großen Anteil am täglichen sedentären Verhalten, insbesondere bei Büroangestellten.
Ziel der Arbeit
In dieser Studie sollte untersucht werden, wie viel Zeit bei verschiedenen Aufgaben am Arbeitsplatz und beim Pendeln von Verwaltungsangestellten einer Universitätsklinik in Deutschland im Sitzen verbracht wird.
Material und Methoden
Eine fragebogengestützte Querschnittsstudie mit Verwaltungsangestellten des Universitätsklinikums Regensburg wurde durchgeführt, um arbeitsbezogenes sedentäres Verhalten zu untersuchen.
Ergebnisse
Die Studienpopulation bestand aus 159 Teilnehmenden (54,1?% Frauen, 51,6?% älter als 40 Jahre), was einer Antwortquote von 26?% entspricht. Die durchschnittliche tägliche Sitzzeit am Arbeitsplatz betrug im Median 7,0?h (Interquartilsbereich [IQR] 6,0?7,5?h) und fand hauptsächlich bei der Computerarbeit statt (57,3?%). Die mittlere Stehzeit bei der Arbeit betrug im Median 0,8?h (IQR 0,3?1,4?h). Verwaltungsangestellte verbrachten während des Pendelns im Median 0,7?h (IQR 0,3?1,0?h) pro Tag im Sitzen. Die Teilnehmenden waren der Ansicht, dass langes und ununterbrochenes Sitzen negative (69,6?%) oder eher negative (29,7?%) Auswirkungen auf die Gesundheit hat.
Diskussion
Verwaltungspersonal in Krankenhäusern verbringt einen großen Teil der täglichen Arbeitszeit mit sedentärem Verhalten. Maßnahmen, die es ermöglichen, sowohl im Sitzen als auch im Stehen zu arbeiten, können zu einer Verringerung der arbeitsbedingten Sitzzeit führen und damit die Gesundheit am Arbeitsplatz und im weiteren Sinne die öffentliche Gesundheit verbessern.
Hospital Frailty Risk Score predicts adverse events in revision total hip and knee arthroplasty
(2021)
Introduction The Hospital Frailty Risk Score (HFRS) is a validated risk stratification model referring to the cumulative deficits model of frailty. The purpose of this study was to evaluate the HFRS as a predictor of 90-day readmission and complications after revision total hip (rTHA) and knee (rTKA) arthroplasty. Methods In a retrospective analysis of 565 patients who had undergone rTHA or rTKA between 2011 and 2019, the HFRS was calculated for each patient. Rates of adverse events were compared between patients with low and intermediate or high frailty risk. Multivariable logistic regression models were used to assess the relationship between the HFRS and post-operative adverse events. Results Patients with intermediate or high frailty risk showed higher rates of readmission (30days: 23.8% vs. 9.9%, p = 0.006; 90days: 26.2% vs. 13.0%, p < 0.018), surgical complications (28.6% vs. 7.8%, p < 0.001), medical complications (11.9% vs. 1.0%, p < 0.001), other complications (28.6% vs. 2.3%, p < 0.001), Clavien-Dindo grade IV complications (14.3% vs. 4.8%, p = 0.009), and transfusion (33.3% vs. 6.1%, p < 0.001). Multivariable logistic regression analyses revealed a high HFRS as independent risk factor for surgical complications (OR = 3.45, 95% CI 1.45-8.18, p = 0.005), medical complications (OR = 7.29, 95% CI 1.72-30.97, p = 0.007), and other complications (OR = 14.15, 95% CI 5.16-38.77, p < 0.001). Conclusion The HFRS predicts adverse events after rTHA and rTKA. As it derives from routinely collected data, the HFRS could be implemented automated in hospital information systems to facilitate identification of at-risk patients.
