Performance Assessment of Electric Energy Storage (EES) Systems Based on Reversible Solid Oxide Cell

Abstract This paper focuses on the performance assessment of a novel and efficient EES (electric energy storage) system based on ReSOC (reversible solid oxide cell) technology. The ReSOC is an electrochemical energy conversion device working at high temperature (600-1000°C) that can operate reversibly either as a fuel cell (SOFC) or as an electrolyzer (SOEC). In this study, a ReSOC unit fed by mixtures of CH4, CO, H2O and H2 is proposed and analyzed. In particular, in the SOFC mode, where electricity is generated, the reactant gas, mainly formed by CH4 and H2, is converted into a mixture of H2O and CO2. The exhausts from the SOFC are used as the reactant gas for the SOEC operation. During the electrolysis process, CH4 can be also produced thanks to the methanation reaction that, under proper operating conditions, occurs at the cathode of the solid oxide cell. The ReSOC unit behavior is investigated by developing a thermo-electrochemical model, able to predict its performance (i.e. roundtrip efficiency, polarization curve, thermally self-sustaining conditions) under different operating conditions. The ReSOC model, built with a modular architecture, is performed through thermodynamic, thermochemical and electrochemical sub-models taking into account mass and energy balances, chemical reactions (reforming, shifting reactions and methanation) and electro-chemical relationships. Available literature data have been used for the model validation and a calibration procedure has been performed in order to evaluate the best fitting values for the model parameters. Furthermore, in order to estimate the thermoneutral conditions in SOEC operating mode, the ReSOC thermal behavior has been analyzed under different operating temperatures. Results pointed out that, by feeding the cell with a syngas mixture, the reforming reaction (in the SOFC mode) and the methanation reaction (in the SOEC mode) allow to simplify the cell thermal management. Moreover, the best performance in terms of stack roundtrip efficiency (about 70%), can be reached operating the ReSOC at low temperature (700°C)

Conventional and Advanced Biomass Gasification Power Plants Designed for Cogeneration Purpose

Abstract In this paper conventional and advanced biomass gasification power plants designed for small cogeneration application are defined. The CHP plants consist of a gasification unit, that employs a downdraft gasifier, and a power unit based on a microturbine in the case of conventional configuration, and on a solid oxide fuel cell module, in the case of advanced configuration. The plants are sized to supply about 100 kW of electrical power. In order to investigate and to analyze the performances of the two plant configurations, in terms of thermal and electrical efficiencies, numerical models have been developed by using thermochemical and thermodynamic codes

Modular tapered conical revision stem in hip revision surgery: mid- term results

Background: The aim of this paper is to evaluate the clinical and radiological outcomes of a fluted tapered modular distal-fixation stem at medium to long-term follow-up. The hypothesis of this investigation was to verify if the use of this implant design may have provided potential advantages in femoral revisions and post-traumatic instances where the restoration of the anatomy was the prime concern. Methods: We retrospectively reviewed 62 cases of femoral revision surgeries, performed in Paprosky type IIIA and IIIB bone defects between January 2001 and December 2011 with a mean follow-up of 8.5 ± 1.5 years (range 5.1–15.9 years) where a modular fluted stem was used. The clinical assessment was performed with the Harris Hip Score (HHS), and the radiographic evaluation was carried in order to assess the stability of the femoral component. Intra-operative and postoperative complications were recorded, and the rates of complications and revisions for any cause were determined. Results: Mean HHS improved 35.4 points from the preoperative assessment. Radiographic evaluation showed a stable stem anchorage in 90.3% of the cases at the last follow-up. Five (8%) implants required additional surgery. Neither breakage of the stem nor loosening of the taper junction were recorded. Kaplan-Meier survivorship was 89.4% (CI: 88.8–90%) for any complication and 92.3% (CI: 91.8–92.7%) according to revision for any causes at 81 months follow-up. Conclusions: Our findings suggest that this stem design is a reliable option in cases of complex femoral bone defects, as well as in cases with high functional deficiencies, with promising survivorship

Controversy: supporting patellar resurfacing in total knee arthroplasty – do it

Patellar resurfacing during total knee arthroplasty remains a controversial topic. Some surgeons routinely resurface the patella to avoid the increased rates of postoperative anterior knee pain and reoperation for secondary resurfacing, whilst others selectively resurface based on the presence of preoperative anterior knee pain, damaged articular cartilage, inflammatory arthritis, isolated patellofemoral arthritis, and patellar subluxation and/or maltracking. A third group of surgeons never resurface the patella. The anatomy and biomechanics of the patellofemoral joint as well as the advances in surgical techniques and prosthetic design must be taken into account when making a decision about whether to resurface the patella. Accurate component implantation if the patella is resurfaced becomes crucial to avoid complications. In our institution before 2008 we were performing a selective resurfacing of the patella, but in the last decade we have decided to always resurface it, with good outcomes and low complication rate. A reproducible surgical technique may be helpful in reducing the risk of postoperative anterior knee pain and complications related to implants. In this article we analyse the current trend and controversial topics in dealing with the patella in total knee arthroplasty, and discuss the available literature in order to sustain our choice

Arthroscopic-guided balloon tibioplasty in schatzker iii tibial plateau fracture

Purpose The study aims to present the results at a mean 28-months follow-up of arthroscopic-guided balloon tibioplasty and to spot some technical tricks and some practice using tools and materials. Methods The study relates to six patients with tibial plateau fractures type Schatzker III with tibial plateau depression more than 4 mm at preoperative computed tomography scan (CT-scan). The follow-up period ranged from 22 to 33 months, with a mean of 28 months. No patients were lost to follow-up. The patients were evaluated clinically using the Rasmussen score system and Lysholm score systems at 6 to 12 and 24 months, postoperatively. Radiographic evaluations (standard X-rays) were done preoperatively at 1, 3, and 12 months postoperatively while a CT-scan with 3D reconstruction was performed preoperatively, at the first day and 6 months, postoperatively. Results The mean Rasmussen clinical score at 6 months postoperatively was 26.3 while at 1-year postoperatively the mean Rasmussen clinical score was 28.33. At 2-year postoperatively the mean Rasmussen clinical score was 28.83. Statistically significant difference was found in 6-months and 2-years results (p < 0.05). CT-scan achieved the first postoperative day showed the recovery of approximately 70% of the area of the interested tibial plateau, restoring of the joint surface without articular bone free fragments. Conclusion The described surgical procedure, if correctly performed with proper indications (Schatzker III), respect the principles mentioned above and the clinical and radiological results confirm our purpose. Level of Evidence This is a therapeutic case series, level IV study

The progression of hemophilic arthropathy: The role of biomarkers

Background: Hemophilia A and B are X-linked congenital bleeding disorders characterized by recurrent hemarthroses leading to specific changes in the synovium and cartilage, which finally result in the destruction of the joint: this process is called hemophilic arthropathy (HA). This review highlights the most prominent molecular biomarkers found in the literature to discuss their potential use in the clinical practice to monitor bleeding, to assess the progression of the HA and the effectiveness of treatments. Methods: A review of the literature was performed on PubMed and Embase, from 3 to 7 August 2020. Study selection and data extraction were achieved independently by two authors and the following inclusion criteria were determined a priori: English language, available full text and articles published in peer-reviewed journal. In addition, further articles were identified by checking the bibliography of relevant articles and searching for the studies cited in all the articles examined. Results: Eligible studies obtained at the end of the search and screen process were seventy-three (73). Conclusions: Despite the surge of interest in the clinical use of biomarkers, current literature underlines the lack of their standardization and their potential use in the clinical practice preserving the role of physical examination and imaging in early diagnosis

Pulsed electromagnetic fields in bone healing: Molecular pathways and clinical applications

In this article, we provide an extensive review of the recent literature of the signaling pathways modulated by Pulsed Electromagnetic Fields (PEMFs) and PEMFs clinical application. A review of the literature was performed on two medical electronic databases (PubMed and Embase) from 3 to 5 March 2021. Three authors performed the evaluation of the studies and the data extraction. All studies for this review were selected following these inclusion criteria: studies written in English, studies available in full text and studies published in peer‐reviewed journal. Molecular biology, identifying cell membrane receptors and pathways involved in bone healing, and studying PEMFs target of action are giving a solid basis for clinical applications of PEMFs. However, further biology studies and clinical trials with clear and standardized parameters (intensity, frequency, dose, duration, type of coil) are required to clarify the precise dose–response relationship and to understand the real applications in clinical practice of PEMFs

Biomarkers for ehlers-danlos syndromes: There is a role?

Ehlers-Danlos syndromes (EDS) are an inherited heterogeneous group of connective tissue disorders characterized by an abnormal collagen synthesis affecting skin, ligaments, joints, blood vessels, and other organs. It is one of the oldest known causes of bruising and bleeding, and it was described first by Hippocrates in 400 BC. In the last years, multiple gene variants involved in the pathogenesis of specific EDS subtypes have been identified; moreover, new clinical diagnostic criteria have been established. New classification models have also been studied in order to differentiate overlapping conditions. Moreover, EDS shares many characteristics with other similar disorders. Although distinguishing between these seemingly identical conditions is difficult, it is essential in ensuring proper patient care. Currently, there are many genetic and molecular studies underway to clarify the etiology of some variants of EDS. However, the genetic basis of the hypermobile type of EDS (hEDS) is still unknown. In this review, we focused on the study of two of the most common forms of EDS—classic and hypermobile—by trying to identify possible biomarkers that could be of great help to confirm patients’ diagnosis and their follow up

Patients with Musculoskeletal Disorders Presenting to the Emergency Department: The COVID-19 Lesson

Background: Musculoskeletal disorders (MSKDs) are the most common class of complaints among patients presenting for care in the Emergency Department (ED). There is a non-urgent patient population with musculoskeletal complaints attending ED services that creates a burgeoning waiting list and contributes to overcrowding in Emergency Departments (EDs), which is a major concern worldwide. The recent (Coronavirus disease-19) COVID-19 pandemic is an unprecedented challenge that is revealing the structural and situational strengths and weaknesses of healthcare systems. Methods: This study retrospectively and prospectively assessed patients presenting to the Emergency Department before and after the COVID-19 outbreak (from 21 February 2019 to 3 May 2019 and from 21 February 2020 to 3 May 2020) with non-traumatic or low-severity musculoskeletal conditions to test the hypothesis that these patients should have access to care outside the ED and that the COVID-19 outbreak has changed patients’ care and health perception. Results: A total of 613 patients were identified, and 542 of them (87.56%) participated in a personalized survey. From this number, 81.73% of the total accesses took place in 2019, and only 18.27% of the accesses took place during the first outbreak and lockdown. More than 90% of patients admitted to the ED accessed care during the day shift in both periods. A total of 87.30% of patients presenting to the ED with a MSKD followed their general practitioner’s (GP) advice/referral in 2019, and 73.87% did so in 2020. The differences in the means of transport to the ED was statistically significant (p-value 0.002). Conclusions: The outbreak and lockdown period confirmed that there is an inappropriate use of the ED related to patients with MSKD. However, the ED appears to be the only available solution for these patients. New services and pathways are therefore needed to enhance MSKD management and reduce ED crowding. Additional observational studies shall be developed to confirm and compare our findings with those of various EDs. The main limit of the inferential part of the study is probably due to the small sample of patients in 2020