University of Alberta

Discontinuous pulsewidth modulation (DPWM) is often adopted in the three-phase (3Φ) grid-connected inverter (GCI) for enhancing the efficiency. However, DPWM will increase common voltage at the neutral point of the filter capacitors and may deteriorate the safe operation of the inverter. To reduce the common voltage, some applications connect the neutral point of the filter capacitors and midpoint of dc voltage. Nevertheless, there may be zero-sequence LC -resonant current in the filter inductor, leading to a larger current ripple and further increasing the power loss. This letter demonstrates the inherent mechanism how DPWM generates the zero-sequence resonance current. On the basis, this letter unveils the straightforward ideas for problem solving, regardless of the DPWM method, and then proposes an easy-implementing solution to reduce it from the perspective of control method, which is different from the state-of-the-art works by modifying modulation method, yet can reserve the efficiency improvement brought from DPWM. Finally, experimental results based on a 3.6-KVA 3Φ GCI prototype are provided to verify the analysis and effectiveness of the proposed method.

Vehicular platooning, a configuration comprising a leading vehicle and multiple follower vehicles (FVs) seeks to achieve and maintain specific intervehicle distances (IDs) while synchronizing FVs with the velocity and acceleration of the leading vehicle. Before attaining a desired stable state, the IDs may undergo transient fluctuations. While the attainment of internal stability is pivotal for realizing the intended spacing between vehicles, it does not inherently guarantee that these transient fluctuations remain within safe thresholds, thereby mitigating the risk of collisions. Communication between vehicles has a critical role in vehicular platooning and significantly influences these transient distance fluctuations. Consequently, we present a mapping between the initial conditions and these transient fluctuations which hinges on the communication topology (CT), as well as the control parameters. Specifically, our focus is directed toward bidirectional CTs (BDCTs), wherein FVs possess the capability to communicate both with preceding and subsequent vehicles within the platoon. Investigation of these mappings illuminates the advantages and disadvantages of various BDCTs. Notably, we discern that within BDCTs, the receipt of information from a greater number of vehicles situated behind may at times hinder the overall performance of the platoon, resulting in larger deviations from the desired IDs or the velocity and acceleration of the leading vehicle. In contrast, information derived from vehicles located ahead, particularly the leading vehicle itself, serves to enhance IDs and therefore contributes significantly to the safety of the platoon. In conclusion, our theoretical insights are substantiated through a series of simulations.

An event-triggered robust model predictive control (MPC) design is proposed for unknown systems using initially measured input-output data. A terminal inequality constraint is developed for the MPC optimization problem without any prior identification, resulting in a larger feasible region and a lower bound for the prediction horizon when compared with a terminal equality constraint. An event-triggered scheme associated with a local controller is designed to trigger the solution of the data-driven MPC optimization problem when necessary, leading to the reduction of resource consumption. Under mild conditions, recursive feasibility and input-to-state stability are guaranteed theoretically. Simulation results are provided to show the effectiveness of the proposed approach.

Ice storms can cause serious damage to power distribution systems, thus the development of effective anti-icing and de-icing strategies is of great significance. In this article, an optimal anti-icing and de-icing coordinated operation scheme is proposed to enhance the resilience of distribution systems against ice storms, which is based on the ice-melting capacity of distribution lines. Firstly, a comprehensive risk analysis for anti-icing and de-icing in ice storms is provided. Then, a novel critical condition for anti-icing initiation is proposed based on the weather forecast deviation and potential load loss in distribution systems. On this basis, the coordinated optimization model for anti-icing and de-icing in distribution networks with intelligent soft open point and energy storage systems is established, aims at minimizing the overall load loss. Considering the double risk of overloading anti-icing and de-icing methods, the power flow limit violation function is used in the optimization model to reasonably allocate the proportion of various risks. Finally, the proposed method is verified in the IEEE 33-node distribution network.

This paper addresses the dynamic stability of a hybrid photovoltaic (PV) and wind turbine (WT) system tied to a weak grid by back-to-back voltage-source converters (VSCs). The overall system stability is assessed by developing a detailed time-domain nonlinear model (TDNLM) and a linearized state-space model (LSSM). The dynamic interactions at both the peak-power point (PPP) and off-PPP operation of the PV and WT power characteristics curves have been examined. The results reveal that the complete system is stable under PV-only and WT-only generation scenarios at the PPP and off-PPP operation regions. However, the PV-WT hybrid system experiences low-and high-frequency fluctuation instabilities in the current-limited region (CLR) of the PV characteristic due to the interaction between the high dynamic resistances of the PV-WT source and the weak grid. Conversely, the system remains stable at the PPP and voltage-limited region (VLR) of the PV characteristic and in all operational regions of the WT characteristic. Motivated by these challenges, a novel active damping method is proposed to mitigate the interaction dynamics, maintaining overall system stability by relocating unstable eigenmodes and reshaping the dc-link transfer function. The proposed damping method offers several benefits: 1) it is simple yet efficient and can be implemented and modeled using linear analysis tools; 2) it allows for dynamic and stable operation across various operating regions; 3) it does not interfere with steady-state performance in both stiff and weak grid operations, 4) it facilitates successful low-voltage-ride-through (LVRT) at different operating regions; and 5) it effectively addresses its shortcomings by eliminating the need for additional voltage or current sensors, thereby enhancing simplicity and reducing cost in comparison to other approaches. Detailed offline and real-time simulations validate the analytical findings and the effectiveness of the proposed stabilization method under different operational scenarios.

Owing to their distinct principles, voltage-fed dual-active-bridge (VF-DAB) and current-fed dual-active-bridge (CF-DAB) converters each exhibit unique strengths and weaknesses, making them appropriate for varying applications. To increase the application flexibility, an alternative-fed dual-active-bridge (AF-DAB) DC/DC converter, with the merits of wide voltage gains and low current ripples, is proposed in this letter. Through the alternative-fed method, the AF-DAB converter can integrate both DABs’ merits while eschewing unsuitable areas. Ultimately, the operation schemes and control structure are elaborated, and the experimental results are presented to verify the superior performance of the proposed topology.

This paper presents new design and control approaches for an input-series-output-parallel (ISOP) connected hybrid converter with partial power processing (PPP) capabilities, which comprises a CLLC converter and a dual-active-bridge (DAB). In this hybrid CLLC-DAB configuration, secondaryside bridges are shared between CLLC and DAB topologies to minimize the number of utilized switches. Incorporating the high efficiency of CLLC with the exceptional control flexibility of DAB, the hybrid configuration transfers the main power through CLLC while enabling DAB to handle partial power flow. The power distribution between CLLC and DAB is optimized, considering system efficiency, dynamic response, etc. Based on the resulting power ratio, system parameters are also optimized, including considerations for soft-switching of all switches in a wide load range, output power capacity, component tolerances, and overall efficiency. Furthermore, the output voltage can be accurately regulated by manipulating the phase shift angle of DAB. To enhance the system's transient performance in scenarios involving varying loads and input voltages, an adaptive fast dynamic response control (AFDRC) strategy exhibiting robustness against variations in system parameters is also proposed. Finally, experimental results validate that the hybrid CLLCDAB system, employing the proposed design methodology and control strategy, attains both high system efficiency and ultrafast dynamic response.

Appropriate identification of burn depth and size is paramount. Despite the development of burn depth assessment aids [e.g., laser doppler imaging (LDI)], clinical assessment, which assesses partial thickness burn depth with 67% accuracy, currently remains the most consistent standard of practice. We sought to develop an image-based artificial intelligence system that predicts burn severity and wound margins for use as a triaging tool in thermal injury management. Modified EfficientNet architecture trained by 1684 mobile-device-captured images of different burn depths were previously utilized to create a convoluted neural network (CNN). The CNN was modified to a novel Boundary-Attention Mapping (BAM) algorithm using elements of saliency mapping, which was utilized to recognize the boundaries of burns. For validation, 144 patient charts that included clinical assessment, burn location, total body surface area, and LDI assessment were retrieved for a retrospective study. The clinical images underwent CNN-BAM assessment and were directly compared with the LDI assessment. CNN using a four-level burn severity classification achieved an accuracy of 85% (micro/macro-averaged ROC scores). The CNN-BAM system can successfully highlight burns from surrounding tissue with high confidence. CNN-BAM burn area segmentations attained a 91.6% accuracy, 78.2% sensitivity, and 93.4% specificity, when compared to LDI methodology. Results comparing the CNN-BAM outputs to clinical and LDI assessments have shown a high degree of correlation between the CNN-BAM burn severity predictions to those extrapolated from LDI healing potential (66% agreement). CNN-BAM algorithm gives equivalent burn-depth detection accuracy as LDI with a more economical and accessible application when embedded in a mobile device.

Pain is a common reason for attendance to the emergency department; however, pediatric specific data on the prevalence, location, and etiology of painful presentations are limited in the literature. Therefore, the objective of this study was to determine the prevalence of pain-related presentations to pediatric emergency departments during the triage process and characterize the anatomical locations and organ systems most affected by pain in a modern cohort. A two-center health record review of triage documentation was conducted at Canadian pediatric emergency departments. All children (< 18 years) were eligible for inclusion. Data were extracted from administrative sources with one week of consecutive patients included every 3 months over a one-year timeframe. Regression analyses were completed to identify variables associated with painful presentations and analgesia provision during the triage process. A total of 7208 emergency department presentations were included. Median [IQR] child age was 5.2 [1.9, 11.8] years and 53.2% were male. 58.8% of children were found to have pain as a component of their triage presentation. Of those with pain (n = 4237), 24.1% had a pain score documented and 13.8% had analgesia provided at triage. Location of pain (n = 4523) was predominantly in the head (38.0%), extremities (27.8%), and abdomen (22.8%). Primary organ systems most affected (n = 4237) included the musculoskeletal (31.1%), gastrointestinal (18.3%), and cutaneous (including lacerations) (14.4%) systems. In this study, pain was identified in almost 60% of all pediatric emergency department presentations at the time of triage. Suboptimal documentation of pain scores and provision of analgesia at triage were found for children with pain. These results support early assessment and implementation of pain management strategies at triage. Results can also focus further research efforts to the management of the most commonly presenting types of pediatric pain.

This paper proposes a Takagi–Sugeno fuzzy system model based fault tolerant control scheme for DC–DC converters, which is robust against parameter uncertainties and achieves the output voltage of an ideal converter. The control involves estimating the duty cycle change in the form of a fault parameter required to track the output voltage, in the presence of several uncertain conditions including converter losses, variation in input voltage, and unknown and changing output load. An adaptive law is designed to estimate the fault parameter that guarantees state and parameter error convergence. The adaptive law is derived using the Lyapunov stability theorem and the required parameters are evaluated by solving a linear matrix inequalities optimization problem. The load resistance is estimated in parallel by using a Kalman filter and fed to the fault parameter estimation scheme. Furthermore, a fast and robust method to detect short and open circuit switch faults is also presented. The proposed technique offers a simple, yet effective method to regulate the output voltage under several faulty and uncertain conditions. The proposed technique is tested on a DC–DC boost converter simulation model and the demonstrated MATLAB/Simulink results show the effectiveness of the proposed algorithm.

Lunatic Fringe (LFNG) is required for spinal development. Biallelic pathogenic variants cause spondylocostal dysostosis type‐III (SCD3), a rare disease generally characterized by malformed, asymmetrical, and attenuated development of the vertebral column and ribs. However, a variety of SCD3 cases reported have presented with additional features such as auditory alterations and digit abnormalities. There has yet to be a single, comprehensive, functional evaluation of causative LFNG variants and such analyses could unveil molecular mechanisms for phenotypic variability in SCD3. Therefore, nine LFNG missense variants associated with SCD3, c.564C>A, c.583T>C, c.842C>A, c.467T>G, c.856C>T, c.601G>A, c.446C>T, c.521G>A, and c.766G>A, were assessed in vitro for subcellular localization and protein processing. Glycosyltransferase activity was quantified for the first time in the c.583T>C, c.842C>A, and c.446C>T variants. Primarily, our results are the first to satisfy American College of Medical Genetics and Genomics PS3 criteria (functional evidence via well‐established assay) for the pathogenicity of c.583T>C, c.842C>A, and c.446C>T, and replicate this evidence for the remaining six variants. Secondly, this work indicates that all variants that prevent Golgi localization also lead to impaired protein processing. It appears that the FRINGE domain is responsible for this phenomenon. Thirdly, our data suggests that variant proximity to the catalytic residue may influence whether LFNG is improperly trafficked and/or enzymatically dysfunctional. Finally, the phenotype of the axial skeleton, but not elsewhere, may be modulated in a variant‐specific fashion. More reports are needed to continue testing this hypothesis. We anticipate our data will be used as a basis for discussion of genotype–phenotype correlations in SCD3.

Background Optimizing a child’s emergency department (ED) experience positively impacts their memories and future healthcare interactions. Our objectives were to describe children’s perspectives of their needs and experiences during their ED visit and relate this to their understanding of their condition. Methods 514 children, aged 7–17 years, and their caregivers presenting to 10 Canadian pediatric EDs completed a descriptive cross-sectional survey from 2018–2020. Results Median child age was 12.0 years (IQR 9.0–14.0); 56.5% (290/513) were female. 78.8% (398/505) reported adequate privacy during healthcare conversations and 78.3% (395/504) during examination. 69.5% (348/501) understood their diagnosis, 89.4% (355/397) the rationale for performed tests, and 67.2% (338/503) their treatment plan. Children felt well taken care of by nurses (90.9%, 457/503) and doctors (90.8%, 444/489). Overall, 94.8% (475/501) of children were happy with their ED visit. Predictors of a child better understanding their diagnosis included doctors talking directly to them (OR 2.21 [1.15, 4.28]), having someone answer questions and worries (OR 2.51 [1.26, 5.01]), and older age (OR 1.08 [1.01, 1.16]). Direct communication with a doctor (OR 2.08 [1.09, 3.99]) was associated with children better understanding their treatment, while greater fear/ ‘being scared’ at baseline (OR 0.59 [0.39, 0.89]) or at discharge (OR 0.46 [0.22, 0.96]) had the opposite effect. Interpretation While almost all children felt well taken care of and were happy with their visit, close to 1/3 did not understand their diagnosis or its management. Children’s reported satisfaction in the ED should not be equated with understanding of their medical condition. Further, caution should be employed in using caregiver satisfaction as a proxy for children’s satisfaction with their ED visit, as caregiver satisfaction is highly linked to having their own needs being met.

This study aims to assess the patterns of life satisfaction with life (SwL), sexual satisfaction, and adjustment to aging (AtA), of older adults in Mexico and Portugal. A sample of 658 older adults, aged 65 years-old and older, from Mexico and Portugal were recruited for this cross-cultural study. The following measures were applied: (a) Adjustment to Aging Scale (ATAS); (b) Satisfaction with Life Scale (SwLS); (c) New Sexual Satisfaction Scale (NSSS); (d) Mini-Mental State Exam; and (e) Sociodemographic, health and lifestyle questionnaire. Clusters were identified and characterized by using K-means cluster analysis, encompassing SwL, AtA, and sexual satisfaction. Sexual well-being differences among clusters were analyzed with One-way ANOVAs. Findings indicated three clusters, which explained 76.4% (R-sq = 0.764) of the total variance: Cluster #1: “Moderately adjusted older adults” (n = 355, 53.9%), Cluster #2: “Moderately fulfilled older adults” (n = 265, 40.3%), and Cluster 3: “Well adjusted and satisfied older adults” (n = 38, 5.8%). Participants in Cluster #1 were mostly Mexican, with moderate levels of AtA and reduced sexual satisfaction and SwL. Conversely, Cluster #2 predominantly consisted of Portuguese participants with moderate sexual satisfaction and SwL, and lower levels of AtA. Participants from Cluster #3 were mostly Portuguese with high levels of AtA, sexual satisfaction, and SwL. This innovative study explored the intricate relationship between sexual well-being, the ability to adjust to aging, and overall SwL, in two different cultural contexts. Findings contributed to the understanding of the relationship between these three variables and for developing tailored future interventions and service planning with older adults in different cultures.

Human pluripotent stem cells (hPSCs) hold promise for regenerative medicine to replace essential cells that die or become dysfunctional. In some cases, these cells can be used to form clusters whose size distribution affects the growth dynamics. We develop models to predict cluster size distributions of hPSCs based on several plausible hypotheses, including (0) exponential growth, (1) surface growth, (2) Logistic growth, and (3) Gompertz growth. We use experimental data to investigate these models. A partial differential equation for the dynamics of the cluster size distribution is used to fit parameters (rates of growth, mortality, etc.). A comparison of the models using their mean squared error and the Akaike Information criterion suggests that Models 1 (surface growth) or 2 (Logistic growth) best describe the data.

A previous network meta-analysis established 16-week relative efficacy with bimekizumab, an inhibitor of interleukin (IL)-17F in addition to IL-17A, versus other treatments for patients with radiographic axial spondyloarthritis (r-axSpA; i.e., ankylosing spondylitis), including the IL-17A inhibitors secukinumab and ixekizumab. This matching-adjusted indirect comparison (MAIC) assessed 52-week relative efficacy of bimekizumab versus secukinumab and ixekizumab. Individual patient data from BE MOBILE 2 (bimekizumab 160 mg; N = 220) were matched to pooled summary data from MEASURE 1/2/3/4 (secukinumab 150 mg), MEASURE 3 (secukinumab 300 mg; escalated dose for inadequate responders), COAST-V (ixekizumab) and COAST-V/-W (ixekizumab). BE MOBILE 2 patients were reweighted using propensity score weights based on age, sex, ethnicity, tumor necrosis factor inhibitor (TNFi) exposure, weight, baseline ASDAS and BASFI (secukinumab) and baseline BASDAI (ixekizumab), and 52-week efficacy outcomes from the trial recalculated. Odds ratios (OR) or mean difference for unanchored comparisons are reported with 95% confidence intervals (CI). At week 52, MAIC demonstrated that patients may have higher likelihood of improvement in key efficacy outcomes with bimekizumab versus secukinumab 150 mg (e.g., ASAS40: [OR (95% CI): 1.48 (1.05, 2.10); p = 0.026]; effective sample size [ESS] = 177). Differences in 52-week efficacy outcomes between bimekizumab and secukinumab 300 mg dose escalation were non-significant (ESS = 120). Bimekizumab versus ixekizumab 80 mg comparisons (COAST-V only; ESS = 84) also suggested that differences were non-significant for most key efficacy outcomes. Other ixekizumab comparisons (COAST-V/-W; ESS = 45) suggested bimekizumab may have higher comparative efficacy for many of the same efficacy outcomes, however ixekizumab analyses were limited by poor population overlap, likely due to the greater proportion of patients with previous TNFi exposure. Patients treated with bimekizumab may have a higher likelihood of achieving improved longer-term efficacy versus secukinumab 150 mg, suggesting bimekizumab may be a favorable therapeutic option for r-axSpA. Differences in efficacy outcomes with bimekizumab versus ixekizumab 80 mg were mostly non-significant, depending on the populations considered.

Understanding the interactions among anthropogenic stressors is critical for effective conservation and management of ecosystems. Freshwater scientists have invested considerable resources in conducting factorial experiments to disentangle stressor interactions by testing their individual and combined effects. However, the diversity of stressors and systems studied has hindered previous syntheses of this body of research. To overcome this challenge, we used a novel machine learning framework to identify relevant studies from over 235,000 publications. Our synthesis resulted in a new dataset of 2396 multiple‐stressor experiments in freshwater systems. By summarizing the methods used in these studies, quantifying trends in the popularity of the investigated stressors, and performing co‐occurrence analysis, we produce the most comprehensive overview of this diverse field of research to date. We provide both a taxonomy grouping the 909 investigated stressors into 31 classes and an open‐source and interactive version of the dataset (https://jamesaorr.shinyapps.io/freshwater‐multiple‐stressors/). Inspired by our results, we provide a framework to help clarify whether statistical interactions detected by factorial experiments align with stressor interactions of interest, and we outline general guidelines for the design of multiple‐stressor experiments relevant to any system. We conclude by highlighting the research directions required to better understand freshwater ecosystems facing multiple stressors.

Objectives The benefits of intravenous thrombolysis are time‐dependent, with maximum efficacy when administered within the first “golden” hour after onset. Nevertheless, the impact of golden hour thrombolysis has not been well quantified. Methods Medline, Embase, and Web of Science databases were systematically searched from inception to August 27, 2023. We included studies that reported safety and efficacy outcomes of ischemic stroke patients treated with intravenous thrombolysis in the golden hour versus later treatment window. The primary outcome was an excellent functional outcome, defined as a modified Rankin Scale score of 0–1 at 90 days. The secondary efficacy outcome was a good functional outcome (defined as modified Rankin Scale score of 0–2). The main safety outcome was symptomatic intracerebral hemorrhage. Results Seven studies involving 78,826 patients met the selection criteria. Golden hour thrombolysis was associated with higher odds of 90‐day excellent functional outcomes (OR 1.40, 95% CI 1.16–1.67) and 90‐day good functional outcomes (OR 1.38, 95% CI 1.13–1.69) compared with thrombolysis outside the golden hour. The number needed to treat to benefit for golden hour thrombolysis to reduce disability by at least 1 level on the modified Rankin Scale per patient was 2.6. Rates of symptomatic intracerebral hemorrhage and mortality were similar between groups. Interpretation Golden hour thrombolysis significantly improved acute ischemic stroke outcomes. The findings provide rationale for intensive efforts aimed at expediting thrombolytic therapy within the golden hour window following the onset of acute ischemic stroke. ANN NEUROL 2024

The Mesozoic intrusions of the Jiaodong Peninsula, eastern China, host giant gold deposits. Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization, which are strongly influenced by the cooling/uplift histories of the hosting intrusions. We performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong Peninsula. The zircon and apatite U-Pb ages are 156.9 ± 1.2 and 137.2 ± 2.4 Ma for the Linglong intrusion, 129.9 ± 1.0 and 125.0 ± 3.8 Ma for the Qujia intrusion, 119.5 ± 0.7 and 117.2 ± 1.8 Ma for the Liulinzhuang intrusion, 118.6 ± 1.0 and 111.6 ± 1.6 Ma for the Nansu intrusion, respectively. The coupled zircon and apatite data of these granitoids indicate a slow cooling rate (11.9 °C/Ma) in the Late Jurassic, and rapid uplift and cooling (35.8–29.2 °C/Ma) in the Early Cretaceous. The dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong Peninsula. This implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.

This paper proposes a hybrid data‐driven and physics‐based simulation technique for seismic response evaluation of steel Buckling‐Restrained Braced Frames (BRBFs) considering brace fracture. Buckling‐Restrained Brace (BRB) fracture is represented by cumulative plastic deformation capacity. A dataset, consisting of 95 past BRB laboratory tests and 120 simulated BRB responses generated using the finite element method, is first developed. An Artificial Neural Network‐based (ANN) predictive model is then trained using the training dataset to estimate the cumulative plastic deformation of BRBs. The prediction capability of the ANN‐based predictive model is validated using the training dataset and an existing regression‐based predictive model. In the second part of the paper, an hybrid simulation technique combining the data‐driven model and physics‐based numerical modeling is presented to conduct the nonlinear time history analysis, followed by 1) validation against a full‐scale BRBF testing and 2) demonstration of the proposed simulation technique using a six‐story BRBF. The results confirm that the proposed predictive model can predict the BRB fracture with sufficient accuracy. Furthermore, the hybrid data‐driven physics‐based simulation technique can be used as a powerful tool for dynamic analysis of BRBFs considering BRB fracture.