Predicting Surgical Outcome in Patients with Recurrent Patellar Dislocation

Introduction Lateral dislocation of the patella is a common injury in active adolescents and young adults. Patients who are ultimately managed surgically have a significantly lower risk of recurrent dislocation. However, determining the optimal surgical treatment remains a challenge, with patients sometimes undergoing multiple surgeries prior to successful stabilization. The aim of this study is to computationally evaluate patients that have undergone multiple surgeries to correct for recurrent lateral patellar dislocation and predict their clinical outcome. Methods Our patient cohort consisted of 16 patients with patella dislocation. Patient-specific imaging were used to create three-dimensional (3D) finite element (FE) models of the knee joint and evaluate patellofemoral (PF) stability at multiple time points pre- and post-surgery for each patient. We applied these models to predict the clinical success or failure of each surgery. Specifically, the FE model simulated a knee extension activity while a tibia external torsion, a recognized cause of patellofemoral pain and instability, was applied to assess PF stability. A healthy control group of 12 participants was also included to assess the ability of the model to identify successful outcomes. In addition, five anatomic factors of risk were measured, and statistical analysis was performed to establish if significant differences exist among pre-surgery, post-surgery and healthy control groups. Lastly, a logistic regression model was implemented, trained with anatomic values, and used to classify subjects into likelihood of dislocation categories in order to differentiate between successful and unsuccessful surgical outcomes. Feature scaling and feature combination (namely, principal component analysis (PCA)) was applied to improve the predictive performance of the regression model. Results Of 12 control participants, 12 pre-surgery subjects (8 patients after an initial unsuccessful MRPLR and 4 without any), and 9 post-surgery subjects (5 after a successful trochleoplasty and 4 patients after MPFLR), the FE model correctly predicted 29 out of 33 surgery outcomes (87.9% accuracy). Post-surgery simulations predicted patellofemoral stability metrics similar to the healthy control group. Particularly, post-trochleoplasty subjects were associated with an increased ability to provide constraint force on the patella lateral facet, and a lower involvement of the medial patellofemoral ligament, particularly close to full extension. A one-way ANOVA showed that four out of five anatomic factors were significantly different between the pre-surgery and the control group, and three of them also between the pre- and post- surgery group, suggesting that the surgery was able to restore a physiological condition. Lastly, logistic regression classification performance demonstrated 72.2% and 78.9% accuracy before and after PCA, respectively. Conclusion The overall aim of this study is to provide surgeons with a useful and validated computational tool that can predict the likelihood of patellar dislocation and differentiate, prior to clinical intervention, between a successful versus unsuccessful surgery, to determine the optimal treatment pathways for individual patients. Preliminary results are promising, but an improvement of the model and a larger clinical dataset are necessary to improve accuracy and comprehensively validate model performance

Environmental-economic analysis of integrated organic waste and wastewater management systems: a case study from Aarhus City (Denmark)

This study presents a comparative analysis of the environmental and economic performances of four integrated waste and wastewater management scenarios in the city of Aarhus in Denmark. The purpose of this analysis is to deliver decision support regarding whether (i) the installation of food waste disposers in private homes (AS1) or (ii) separate collection and transport of organic waste to biogas plants is a more viable environmental and economic solution (AS2). Higher environmental benefits, e.g., mitigation of human health impacts and climate change, are obtained by transforming the existing waste combustion system into scenario (ii). Trade-offs in terms of increased marine eutrophication and terrestrial ecotoxicity result from moving up the waste hierarchy; i.e., from waste incineration to biogas production at wastewater treatment plants with anaerobic sludge digestion. Scenario (i) performs with lower energy efficiency compared to scenario (ii). Furthermore, when considering the uncertainty in the extra damage cost to the sewer system that may be associated to the installation of food waste disposers, scenario (ii) is the most flexible, robust, and less risky economic solution. From an economic, environmental, and resource efficiency point of view, separate collection and transport of biowaste to biogas plants is the most sustainable solution

Assessing the performance of the Gaussian Process Regression algorithm to fill gaps in the time-series of daily actual evapotranspiration of different crops in temperate and continental zones using ground and remotely sensed data

The knowledge of crop evapotranspiration is crucial for several hydrological processes, including those related to the management of agricultural water sources. In particular, the estimations of actual evapotranspiration fluxes within fields are essential to managing irrigation strategies to save water and preserve water resources. Among the indirect methods to estimate actual evapotranspiration, ETa, the eddy covariance (EC) method allows to acquire continuous measurement of latent heat flux (LE). However, the time series of EC measurements are sometimes characterized by a lack of data due to the sensors' malfunctions. At this aim, Machine Learning (ML) techniques could represent a powerful tool to fill possible gaps in the time series. In this paper, the ML technique was applied using the Gaussian Process Regression (GPR) algorithm to fill gaps in daily actual evapotranspiration. The technique was tested in six different plots, two in Italy, three in the United States of America, and one in Canada, with different crops and climatic conditions in order to consider the suitability of the ML model in various contexts. For each site, the climate variables were not the same, therefore, the performance of the method was investigated on the basis of the available information. Initially, a comparison of ground and reanalysis data, where both databases were available, and between two different satellite products, when both databases were available, have been conducted. Then, the GPR model was tested. The mean and the covariance functions were set by considering a database of climate variables, soil water status measurements, and remotely sensed vegetation indices. Then, five different combinations of variables were analyzed to verify the suitability of the ML approach when limited input data are available or when the weather variables are replaced with reanalysis data. Cross-validation was used to assess the performance of the procedure. The model performances were assessed based on the statistical indicators: Root Mean Square Error (RMSE), coefficient of determination (R2), Mean Absolute Error (MAE), regression coefficient (b), and Nash-Sutcliffe efficiency coefficient (NSE). The quite high Nash Sutcliffe Efficiency (NSE) coefficient, and the root mean square error (RMSE) low values confirm the suitability of the proposed algorithm

Is it beneficial to use biogas in the Danish transport sector?–An environmental-economic analysis

Denmark is ambitious in the green transition of its transport sector. The biogas has potentials to substitute diesel as the vehicle fuel. In this paper, we examine the whole chain of biogas utilisation (biomass supply, biogas production and distribution, and fuel substitution) from both economic and environmental perspectives. We find that with low/high biomass supply potentials, the saved greenhouse gas emissions range from 0.89 to 1.66 million tons/2.19 to 4.27 million tons CO2e (carbon dioxide equivalent). The soil carbon stock could increase 52310/124770 tons with low/high biomass supply potentials (measured as remaining carbon in soil 100 years after application of digestate into soil). The biogas plant owners can obtain a return of investment ranging from 10.78% to 13.62% depending on biomass supply potentials and biogas production technologies. The farmers can save up to 717.93 and 1382.1 million DKK (Danish krone ) by substituting mineral P (phosphorus) and N (nitrogen) fertilisers in low biomass supply potential scenarios and 1.74 and 3.44 billion DKK in high biomass supply potential scenarios. Finally, the vehicle users have incentives to use biogas because of its cost advantage. However, there are also some potential barriers and uncertainties in achieving the green transition, e.g. initial investment for CO2 conversion equipment and diesel-vehicle users' sunk costs, which could require suitable policy supports. We suggest that using biogas in heavy-duty vehicles could be an effective way to reduce carbon emissions in the transport sector

Environmental Assessment of Alternatives for Biowaste Treatment in Mexico City

This paper aims to determine the environmental performance of the current landfill gas management system (based on flaring) in Mexico City (Bordo Poniente) in comparison to the collection of biogas generated from solid waste through one of the most innovative technology implemented in Denmark (Aikan Technology), which produces biogas and digestate from waste. Two alternative scenarios are proposed in which the Aikan Technology is implemented in Bordo Poniente to replace the existing system (reference scenario) that involves landfilling inorganic waste and composting organic waste in Bordo Poniente with no biogas recovery. The biogas recovered through Aikan Technology is exploited to provide heat and electricity (Scenario 1) or biofuel for the transportation sector (Scenario 2). A comparative life cycle assessment (LCA) was performed to evaluate the environmental performances associated with all scenarios by evaluating the impact categories Climate Change, Fossil Depletion, and Cumulative Energy Demand. According to the waste capacity of Bordo Poniente, the implementation of the Aikan Technology would result in a total annual reduction of 0.14 and 0.08 Mt of CO2 eq for Scenario 1 and Scenario 2, respectively. Scenario 1 was also the best performing scenario with respect to fossil depletion (−52 kg oil eq ton−1 of organic waste) and cumulative energy demand (−3,557 MJ ton−1 of organic waste). The implementation of Aikan Technology in Mexico City represents an important challenge and requires further research into its economic and political feasibility. When it comes to tackling global environmental problems, international agreements ascribe high importance to environmental technology transfer. This study represents a preliminary step in terms of environmental assessment and thus provides important information for policymakers attempting to achieve more sustainable management of solid waste in Mexico

Clinical Performance of Two Methods for Detecting Anti SARS-CoV-2 Antibodies

Evaluating the clinical performance of available methods to detect antibodies against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has become a primordial issue in clinical laboratories. The aim of this study was to evaluate the clinical performance of two methods for SARS-CoV-2 antibodies detection, an automated Chemiluminescent Immunoassay (CLIA) and an immunochromatographic Lateral-Flow Assay (LFA) in patients with positive reverse transcription polymerase chain reaction (RT-PCR). Performance for CLIA method was Positive Agreement (PA) 56.6% and Negative Agreement (NA) 96,6% for IgM and PA 85.8%/NA 90,2% for IgG. Performance for LFA method was PA 56.2% and NA 100% for IgM and PA 95.5% and NA 100 % for IgG. LFA general agreement IgG was better than CLIA. In both methods, significant differences in Kappa index are observed when IgG and IgM are compared. When evaluating the data from a clinical perspective, we found that both method performance for IgM detection may not meet the expected requirements for their clinical utility and could lead to an inappropriate medical decision. The findings of this study show that both immunoassay methods might be reliable for assessing immunological response in COVID-19 patients. Our results also confirm that IgG measurement could be helpful, especially for epidemiological studies in our population. These results provide evidence to justify epidemiological studies in our population.Fil: Jacobsen, Dario Gustavo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Gonzalez, D.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Fisiopatología y Bioquímica Clínica; ArgentinaFil: Jamardo, J.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Ibar, C.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Pugliese, L.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Fortuna, F.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; ArgentinaFil: Carrizo, E.. Coordinadora de Salud Misionar; ArgentinaFil: Caro, E. M.. Laboratorio Biogenar; ArgentinaFil: Perazzi, Beatriz Elizabeth. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Fisiopatología y Bioquímica Clínica; ArgentinaFil: Repetto, Esteban Martín. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Reboredo, G.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Fabre, B.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Bioquímica Clínica; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Fisiopatología y Bioquímica Clínica; Argentin

The kinematics of fixed-seat rowing : a structured synthesis

Olympic-style sliding-seat rowing is a sport that has been extensively researched, with studies investigating aspects related to the physiology, biomechanics, kinematics, and the performance of rowers. In contrast, studies on the more classic form of fixed-seat rowing are sparse. The aim of this study is to address this lacuna by analysing for the first time the specific kinematics of fixed-seat rowing as practised by able-bodied athletes, thus (i) documenting how this technique is performed in a manner that is replicable by others and (ii) showing how this technique compares and contrasts with the more standard sliding-seat technique. Fixed-seat rowing was replicated in a biomechanics laboratory where experienced fixed-seat rowers, marked with reflective markers following the modified Helen–Hayes model, were asked to row in a manner that mimics rowing on a fixed-seat boat. The findings from this study, complimented with data gathered through the observation of athletes rowing on water, were compared to sliding-seat ergometer rowing and other control experiments. The results show that, in fixed-seat rowing, there is more forward and backward thoracic movement than in sliding-seat rowing (75–77° vs. 44–52°, p < 0.0005). Tilting of the upper body stems was noted to result from rotations around the pelvis, as in sliding-seat rowing, rather than from spinal movements. The results also confirmed knee flexion in fixed-seat rowing with a range of motion of 30–35°. This is less pronounced than in standard-seat rowing, but not insignificant. These findings provide a biomechanical explanation as to why fixed-seat rowers do not have an increased risk of back injuries when compared with their sliding-seat counterparts. They also provide athletes, coaches, and related personnel with precise and detailed information of how fixed-seat rowing is performed so that they may formulate better and more specific evidence-based training programs to meliorate technique and performance.peer-reviewe