Contact between the components of a knee prosthesis: numerical and experimental study

The aim of this work is the analysis of the contact area in a knee prosthesis using two different approaches. In particular, the interface between the femoral component and the polyethylene insert has been studied both numerically and experimentally. The interest in studying the contact area is related to the fact that the wear of the polyethylene insert, due to the high contact pressures, represents one of the major causes of failure of the total knee prosthesis. The possibility to evaluate the contact area at different loads and mutual position between femur and tibia is, therefore, of fundamental importance to study the service life of a prosthesis and to improve its performance. The finite element numerical approach has required the acquisition, through reverse engineering, and CAD modelling of the prosthetic components. Then the FEM simulations have been developed considering two different load conditions. In order to compare the calculated data, the same load configurations have been used for experimental tests based on ultrasonic method. In this case, some preliminary tests were required to calibrate the system depending on the particular characteristics of materials, geometries and surface finish of the prosthesis.The results show a good correlation between the data obtained with the two different approaches and, consequently, a good level of reliability of the procedures developed for the numerical and experimental evaluation of the contact area. The numerical procedure can be used to determine the area for different angles and loads, but especially in the design phase. The ultrasonic technique can be used to validate the numerical data

Contact between the components of a knee prosthesis: numerical and experimental study

The aim of this work is the analysis of the contact area in a knee prosthesis using two different approaches. In particular, the interface between the femoral component and the polyethylene insert has been studied both numerically and experimentally. The interest in studying the contact area is related to the fact that the wear of the polyethylene insert, due to the high contact pressures, represents one of the major causes of failure of the total knee prosthesis. The possibility to evaluate the contact area at different loads and mutual position between femur and tibia is, therefore, of fundamental importance to study the service life of a prosthesis and to improve its performance. The finite element numerical approach has required the acquisition, through reverse engineering, and CAD modelling of the prosthetic components. Then the FEM simulations have been developed considering two different load conditions. In order to compare the calculated data, the same load configurations have been used for experimental tests based on ultrasonic method. In this case, some preliminary tests were required to calibrate the system depending on the particular characteristics of materials, geometries and surface finish of the prosthesis.The results show a good correlation between the data obtained with the two different approaches and, consequently, a good level of reliability of the procedures developed for the numerical and experimental evaluation of the contact area. The numerical procedure can be used to determine the area for different angles and loads, but especially in the design phase. The ultrasonic technique can be used to validate the numerical data

Virtual reality and live scenario simulation: options for training medical students in mass casualty incident triage

Introduction Multicasualty triage is the process of establishing the priority of care among casualties in disaster management. Recent mass casualty incidents (MCI) revealed that health personnel are unfamiliar with the triage protocols. The objective of this study is to compare the relative impact of two simulation-based methods for training medical students in mass casualty triage using the Simple Triage and Rapid Treatment (START) algorithm. Methods A prospective randomized controlled longitudinal study. Medical students enrolled in the emergency medicine course were randomized into two groups (A and B). On day 1, group A students were exposed to a virtual reality (VR) scenario and group B students were exposed to a live scenario (LS), both exercises aiming at triaging 10 victims in a limited period of time (30 seconds/victim). On day 2 all students attended a 2-hour lecture about medical disaster management and START. On day 3 group A and B students were exposed to a LS and to a VR scenario respectively. The vital signs and clinical condition of the 10 victims were identical in the two scenarios. Ability of the groups to manage a simulated triage scenario was then compared (times and triage accuracy). Results Groups A and B were composed of 25 and 28 students respectively. During day 1 group A LS triage accuracy was 58%, while the average time to assess all patients was 4 minutes 28 seconds. The group B VR scenario triage accuracy was 52%, while the average time to complete the assessment was 5 minutes 18 seconds. During day 3 the triage accuracy for group A VR simulation was 92%, while the average time was 3 minutes 53 seconds. Group B triage accuracy during the LS was 84%, with an average time of 3 minutes 25 seconds. Triage scores improved significantly during day 3 (P < 0.001) in the two groups. The time to complete each scenario decreased significantly from day 1 to day 3. Conclusions The study demonstrates that the training course generates significant improvement in triage accuracy and speed. It also reveals that VR simulation compared to live exercises has equivalent results in prompting critical decisions in mass casualty drills. In the beginning the average time to complete the VR scenario was higher than the LS. This could be due to the fact that on day 1 very detailed VR victims created a higher challenge for untaught students. However, the higher triage accuracy recorded at the end of day 3 in VR could be explained by a lower stress level compared to the LS, which could be creating a more stressful environment in taught students

Comparison of two disaster drills' management performed by trained and not-trained students: key times evaluation

Introduction The aim of this report is to compare two disaster exercises' management of students with different backgrounds. To our knowledge nobody has ever compared two exercises, probably because of the difficulty in their evaluation. We implemented a tool for an objective evaluation [1] and we used it for this purpose. Methods Both drills represented a ceiling collapse over a crowded room with a similar amount of casualties and similar severity index. The START triage system was used. The trained students (T) were attending the European Master in Disaster Medicine (EMDM), while the not-trained students (NT) were at the beginning of an introductory course in disaster medicine. During the exercises we recorded key victim-provider interaction times [2] using victim-based data collection. Each victim had their own data card to record triage and time information. Results In this preliminary report we present data regarding the scene length of stay (LOS) and triage to collecting area/advanced medical post time (T-AMP). The LOS was 67.5 (50.0 to 111.0) minutes (25 to 75 IQR) for T as compared with 145.0 (110.0 to 150.0) minutes (25 to 75 IQR) for NT (P < 0.001). Stratification according to assigned triage code showed no difference for high-priority codes (reds and yellows) as opposed to the green code (55.0 (47.0 to 75.0) minutes for T vs 145.0 (141.0 to 155.0) minutes for NT with P < 0.01). T-AMP was 10.0 (3.0 to 34.5) minutes for T as compared with 63.5 (19.5 to 104.3) minutes for NT (P < 0.001). Stratification according to triage code showed no difference for red codes between T and NT but showed a difference for yellow codes (36.5 (15.0 to 82.0) vs 71.0 (30.0 to 99.0) minutes) and green codes (7.0 (3.0 to 12.0) vs 85.0 (17.3 to 115.0) minutes) with P < 0.01. Conclusions Both teams evacuated red codes before the yellow ones in similar time. T-AMP was shorter considering global, yellow and green codes for T as opposed to NT. Global and green LOS was also shorter in the T group as opposed to NT. Training seems to influence global exercise management, less affecting red codes but with an impact on yellow and green evacuation strategies

The impact of fixed triple therapy with beclometasone/formoterol/glycopyrronium on health status and adherence in chronic obstructive pulmonary disease (COPD) in an italian context of real life: The TRITRIAL study protocol

Background: The fixed triple combination Beclometasone dipropionate/Formoterol fuma- rate/Glycopyrronium (BDP/FF/G, Trimbow\uae), an extrafine formulation in a unique pressur- ized metered dose inhaler, is indicated for the maintenance treatment in adult patients with moderate to severe COPD, not adequately treated by ICS/LABA or LABA/LAMA. Besides the evidence from three randomized controlled trials, the impact of fixed triple therapy has not been extensively evaluated in a real-world population of COPD patients. TRITRIAL (TRIple Therapy in Real life: Impact on Adherence and HeaLth status) is a non- interventional study to assess the effect of BDP/FF/G in a real world setting in Italy. Design: TRITRIAL is a 12-month, multicenter, cohort, prospective, longitudinal observational study. Two follow-up visits will be performed at 6 and 12 months, respectively. The study includes the collection of anamnestic clinical and functional data before the start of BDP/FF/G. The study is built for digital conduction, from signature of the informed consent on a dedicated web platform, to the collection of questionnaires and clinical data on the eCRF. Population: A total of 800 patients with COPD ranging from Global Initiative for Obstructive Lung Disease (GOLD) stages 2 to 4, receiving therapy with BDP/FF/G accord- ing to the Summary of Product Characteristics and local clinical practice, will be recruited. All concomitant therapies will be permitted for the duration of the study. Evaluations: The primary endpoint is the change of CAT score at 12 months versus baseline. Secondary endpoints are adherence, health-related quality of life, sleep quality, disease-related outcomes (lung function and COPD exacerbations), device usability, eco- nomic resources consumption, and safety. Conclusion: TRITRIAL study is expected to give relevant information about effectiveness of BDP/FF/G fixed triple therapy in a real-life setting of patients with COPD, where adherence, usability of inhalers and patient\u2019s preference of the device are crucial factors for the success of the therapy

Acid-induced aggregation and gelation of heat-treated chia proteins

This work studied for the first time the acid-induced aggregation and gelation of heat-treated chia protein isolates obtained by extraction at pH 10 or 12 (CPI10 and CPI12, respectively). The aggregation state of proteins was modified during acidification. The size of the aggregates was reduced for both samples when the pH decreased but below pH 4.5 further protein aggregation took place for CPI12. Gelation of CPI12 was completed after about 30 min of acidification with glucone-δ-lactone. By contrast, this period was not enough to reach a constant value in G′ for CPI10. When gelation was ensured, confocal laser scanning micrographs from those gels revealed a coarse and irregular structure with large pores (median size of diameters: 30 μm). Instead, micrographs from CPI12 cold gels showed a more regular and interconnected network, with smaller pores (median size of diameters: 9 μm). These differences are consistent with a higher elastic behaviour ((Formula presented.) = 13.6 ± 0.1 Pa).Fil: López, Débora Natalia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería-Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Ingrassia, Romina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Busti, Pablo Andres. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; ArgentinaFil: Wagner, Jorge Ricardo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Boeris, Valeria. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería-Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Spelzini, Darío. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química y Física. Área Fisicoquímica; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Facultad de Química e Ingeniería-Rosario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentin