Design and prototype validation of a laterally mounted powered hip joint prothesis

Prosthetic technology has advanced with the development of powered prostheses to enhance joint function and movement in the absence of native anatomy. However, there are no powered solutions available for hip-level amputees, and most existing hip prostheses are mounted to the front of the prosthetic socket, thereby limiting range of motion. This research introduces a novel laterally mounted powered hip joint (LMPHJ) that augments user movement. The LMPHJ is mounted on the lateral side of the prosthetic socket, positioning the hip joint closer to the anatomical center of rotation while ensuring user safety and stability. The motor and electronics are located in the thigh area, maintaining a low profile while transmitting the required hip moment to the mechanical joint center of rotation. A prototype was designed and manufactured, and static testing was complete by modifying the loading conditions defined in the ISO 15032:2000 standard to failure test levels for a 100 kg person, demonstrating the joint's ability to withstand everyday loading conditions. Functional testing was conducted using a prosthesis simulator that enabled able-bodied participants to successfully walk with the powered prosthesis on level ground. This validates the mechanical design for walking and indicates the LMPHJ is ready for evaluation in the next phase with hip disarticulation amputee participants.

Impact of bacterial admixtures on the compressive and tensile strengths, permeability, and pore structure of ternary mortars: Comparative study of ureolytic and phototrophic bacteria

The addition of bacterial biomass to cementitious materials can improve strength and permeability properties by altering the pore structure. Photoautotrophic bacteria are understudied mortar bio-additives that do not produce unwanted by-products compared to commonly studied ureolytic species. This study directly compares the impact of the addition of heterotrophic Bacillus subtilis to photoautotrophic Synechocystis sp. PCC6803 on mortar properties and microstructure. Cellulose fibers were used as a bacteria carrier. A commercial concrete healing agent composed of dormant bacterial spores was also tested. Strength, water absorption tests, mercury intrusion porosimetry, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy were applied to experimental mortar properties. The photoautotrophic modifications had a stronger positive impact on mortar strength and permeability properties than sporulated heterotrophic modifications due to differences in surface properties and production of exopolysaccharides. The findings provide support for photoautotrophic species as additives for mortars to move away from ammonia-generating species.

Low- and high-volume blood-flow restriction treadmill walking both improve maximal aerobic capacity independently of blood volume

AIM

Assess the effect of low- and high-volume blood flow restriction training (BFR) on maximal aerobic capacity (VO2 max) and determine if alteration in VO2 max is mediated through changes in hemoglobin mass (Hbmass) and blood volume.

METHODS

Participants' Hbmass (CO-rebreathe), single, and double-leg VO2 max and blood volume regulating hormonal responses (renin and copeptin) were measured before and after BFR training. Training consisted of treadmill walking either (1) twice-daily for 4week (CON and BFRHV ) or (2) twice-weekly for 6week (BFRLV ). Each session consisted of five intervals (3 min, 5% incline, 5 km/h, 100% of lowest occlusion pressure), with 1 min of standing rest between sets.

RESULTS

VO2 max increased using both training exposures, in as quickly as 2-weeks (BFRLV baseline to 4week: +315 ± 241 mL (8.7%), p = 0.02; BFRHV baseline to 2week: +360 ± 261 mL (7.9%), p < 0.01), for the BFRLV and BFRHV groups, with no change in CON. Single- and double-leg VO2 max improved proportionately (single/double-leg VO2 max ratio: BFRLV 78 ± 4.9-78 ± 5.8%, BFRHV 79 ± 6.5-77 ± 6.5%), suggesting that the mechanism for increased VO2 max is not solely limited to central or peripheral adaptations. Hbmass remained unchanged across groups (CON: +10.2 ± 34 g, BFRLV : +6.6 ± 42 g, BFRHV : +3.2 ± 44 g; p = 0.9), despite a significant release of blood volume regulating hormones after initial BFR exposure (renin +20.8 ± 21.9 ng/L, p < 0.01; copeptin +22.0 ± 23.8 pmol/L, p < 0.01), which was blunted following BFRHV training (renin: +13.4 ± 12.4 ng/L, p = 0.09; copeptin: +1.9 ± 1.7 pmol/L, p = 0.98).

CONCLUSION

BFR treadmill walking increases VO2 max irrespective of changes in Hbmass or blood volume despite a large release of blood volume regulating hormones in response to BFR treadmill walking.

Successful reversal of transgene silencing in Chlamydomonas reinhardtii

Chlamydomonas reinhardtii has been successfully engineered to produce compounds of interest following transgene integration and heterologous protein expression. The advantages of this model include the availability of validated tools for bioengineering, its photosynthetic ability, and its potential use as biofuel. Despite this, breakthroughs have been hindered by its ability to silence transgene expression through epigenetic changes. Histone deacetylases (HDAC) are main players in gene expression. We hypothesized that transgene silencing can be reverted with chemical treatments using HDAC inhibitors. To analyze this, we transformed C. reinhardtii, integrating into its genome the mVenus reporter gene under the HSP70-rbcs2 promoter. From 384 transformed clones, 88 (22.9%) displayed mVenus positive (mVenus+ ) cells upon flow-cytometry analysis. Five clones with different fluorescence intensities were selected. The number of integrated copies was measured by qPCR. Transgene expression levels were followed over the growth cycle and upon SAHA treatment, using a microplate reader, flow cytometry, RT-qPCR, and western blot analysis. First, we observed that expression varies with the cell cycle, reaching a maximum level just before the stationary phase in all clones. Second, we uncovered that supplementation with HDAC inhibitors of the hydroxamate family, such as vorinostat (suberoylanilide-hydroxamic-acid, SAHA) at the initiation of culture increases the frequency (% of mVenus+ cells) and the level of transgene expression per cell over the whole growth cycle, through histone deacetylase inhibition. Thus, we propose a new tool to successfully trigger the expression of heterologous proteins in the green algae C. reinhardtii, overcoming its main obstacle as an expression platform.

Predictive Models for Canadian Healthcare Workers Mental Health During COVID-19

PURPOSE

COVID-19 impact on the population's mental health has been reported worldwide. Predicting healthcare workers' mental health and life stress is needed to proactively plan for future emergencies.

DESIGN

Statistics Canada has surveyed Canadian healthcare workers and those working in healthcare settings to gauge their perceived mental health and perceived life stress.

SETTING

A cross-sectional survey of healthcare workers in Canada.

SUBJECTS

A sample of 18,139 healthcare workers respondents.

ANALYSIS

Eight algorithms, including Logistic Regression, Random Forest (RF), Naive Bayes (NB), K Nearest Neighbours (KNN), Adaptive boost (AdaBoost), Multi-layer perceptron (MLP), XGBoost, and LightBoost. AUC scores, accuracy and precision were measured for all models.

RESULTS

XGBoost provided the highest performing model AUC score (AUC = 82.07%) for predicting perceived mental health, and Random Forest performed the best for predicting perceived life stress (AUC = 77.74%). Perceived health, age group of participants, and perceived mental health compared to before the pandemic were found to be the most important 3 features to predict perceived mental health and perceived stress. Perceived mental health compared to before the pandemic was the most important predictor for perceived life stress.

CONCLUSION

Our models are highly predictive of healthcare workers' perceived mental health and life stress. Implementing scalable, non-expensive virtual mental health solutions to address mental health challenges in the workplace could mitigate the impact of workplace conditions on healthcare workers' mental health.

What Makes A Bank A Bank? Differences and Commonalities in Credit Calculation, Application, and Risks in Mitigation Banks Targeting Freshwater Fish Species and Associated Ecosystems

Mitigation banking is part of the ever-expanding global environmental market framework that aims to balance negative approved anthropogenic impacts versus third-party provided ecosystem benefits, sold in the form of credits. Given the need to conserve freshwater biodiversity and habitat, banking has received great traction for freshwater species and systems. While extensive reviews and studies have been conducted on evaluating if equivalency between impacts and offset can be achieved, there is almost no research being done on the way credits are being generated and banks are managed to inform future best practice and policy. Synthesizing banking data through cluster analyzes from 26 banks in the United States generating credits for freshwater species and associated systems, we show two generalizable approaches: removing barriers and targeting whole communities. Both address crucial freshwater conservation needs but come with their risks and caveats. Using common characteristics and management practices founded in federal and district level guidance within these two groups, we showcase and conclude that credit generation via barrier removal can be at risk of granting credit generation for too large of an area, leading to over-crediting. Banks targeting whole freshwater communities and accounting for landscape-level interactions and influences can potentially be detrimental for species on an individual level and large-scale credit availability as well as transfer can incentivize non-compliance with the mitigation hierarchy.

Privacy-preserving analysis of time-to-event data under nested case-control sampling

Analyses of distributed data networks of rare diseases are constrained by legitimate privacy and ethical concerns. Analytical centers (e.g. research institutions) are thus confronted with the challenging task of obtaining data from recruiting sites that are often unable or unwilling to share personal records of participants. For time-to-event data, recently popularized disclosure techniques with privacy guarantees (e.g., Differentially Private Generative Adversarial Networks) are generally computationally expensive or inaccessible to applied researchers. To perform the widely used Cox proportional hazards regression, we propose an easy-to-implement privacy-preserving data analysis technique by pooling (i.e. aggregating) individual records of covariates at recruiting sites under the nested case-control sampling framework before sharing the pooled nested case-control subcohort. We show that the pooled hazard ratio estimators, under the pooled nested case-control subsamples from the contributing sites, are maximum likelihood estimators and provide consistent estimates of the individual level full cohort HRs. Furthermore, a sampling technique for generating pseudo-event times for individual subjects that constitute the pooled nested case-control subsamples is proposed. Our method is demonstrated using extensive simulations and analysis of the National Lung Screening Trial data. The utility of our proposed approach is compared to the gold standard (full cohort) and synthetic data generated using classification and regression trees. The proposed pooling technique performs to near-optimal levels comparable to full cohort analysis or synthetic data; the efficiency improves in rare event settings when more controls are matched on during nested case-control subcohort sampling.

Heterologous expression of NoxA confers aerotolerance in Clostridium sporogenes

Clostridium is a genus of gram-positive obligate anaerobic bacteria. Some species of Clostridium, including Clostridium sporogenes, may be of use in bacteria-mediated cancer therapy. Spores of Clostridium are inert in healthy normoxic tissue but germinate when in the hypoxic regions of solid tumors, causing tumor regression. However, such treatments fail to completely eradicate tumors partly because of higher oxygen levels at the tumor's outer rim. In this study, we demonstrate that a degree of aerotolerance can be introduced to C. sporogenes by transfer of the noxA gene from Clostridium aminovalericum. NoxA is a water-forming NADH oxidase enzyme, and so has no detrimental effect on cell viability. In addition to its potential in cancer treatment, the noxA-expressing strain described here could be used to alleviate challenges related to oxygen sensitivity of C. sporogenes in biomanufacturing.

Distinct trophic ecologies of zooplankton size classes are maintained throughout the seasonal cycle

Marine food webs are strongly size-structured and size-based analysis of communities is a useful approach to evaluate food webs in a way that can be compared across systems. Fatty acid analysis is commonly used to identify diet sources of species, offering a powerful complement to stable isotopes, but is rarely applied to size-structured communities. In this study, we used fatty acids and stable isotopes to characterize size-based variation in prey resources and trophic pathways over a nine-month temperate coastal ocean time series of seven plankton size classes, from > 0.7-μm particulate organic matter through > 2000-μm zooplankton. Zooplankton size classes were generally distinguishable by their dietary fatty acids, while stable isotopes revealed more seasonal variability. Fatty acids of zooplankton were correlated with those of their prey (particulate organic matter and smaller zooplankton) and identified trophic pathways, including widespread ties to the microbial food web. Diatom fatty acids also contributed to zooplankton but fall blooms were more important than spring. Concurrent isotope-based trophic position estimates and fatty acid markers of carnivory showed that some indicators (18:1ω9/18:1ω7) are not consistent across size classes, while others (DHA:EPA) are relatively reliable. Both analysis methods provided distinct information to build a more robust understanding of resource use. For example, fatty acid markers showed that trophic position was likely underestimated in 250-μm zooplankton, probably due to their consumption of protists with low isotopic fractionation factors. Applying fatty acid analysis to a size-structured framework provides more insight into trophic pathways than isotopes alone.

Identification of CD38, CD97, and CD278 on the HIV surface using a novel flow virometry screening assay

While numerous cellular proteins in the HIV envelope are known to alter virus infection, methodology to rapidly phenotype the virion surface in a high throughput, single virion manner is lacking. Thus, many human proteins may exist on the virion surface that remain undescribed. Herein, we developed a novel flow virometry screening assay to discover new proteins on the surface of HIV particles. By screening a CD4+ T cell line and its progeny virions, along with four HIV isolates produced in primary cells, we discovered 59 new candidate proteins in the HIV envelope that were consistently detected across diverse HIV isolates. Among these discoveries, CD38, CD97, and CD278 were consistently present at high levels on virions when using orthogonal techniques to corroborate flow virometry results. This study yields new discoveries about virus biology and demonstrates the utility and feasibility of a novel flow virometry assay to phenotype individual virions.

Practical Applications of a Set-Based Camera Deployment Methodology

This work establishes a complete methodology for solving continuous sets of camera deployment solutions for automated machine vision inspection systems in industrial manufacturing facilities. The methods presented herein generate constraints that realistically model cameras and their associated intrinsic parameters and use set-based solving methods to evaluate these constraints over a 3D mesh model of a real part. This results in a complete and certifiable set of all valid camera poses describing all possible inspection poses for a given camera/part pair, as well as how much of the part's surface is inspectable from any pose in the set. These methods are tested and validated experimentally using real cameras and precise 3D tracking equipment and are shown to accurately align with real imaging results according to the hardware they are modelling for a given inspection deployment. In addition, their ability to generate full inspection solution sets is demonstrated on several realistic geometries using realistic factory settings, and they are shown to generate tangible, deployable inspection solutions, which can be readily integrated into real factory settings.

Validation of Automatically Quantified Swim Stroke Mechanics Using an Inertial Measurement Unit in Paralympic Athletes

Biomechanics and training load monitoring are important for performance evaluation and injury prevention in elite swimming. Monitoring of performance and swim stroke parameters is possible with inertial measurement units (IMU) but has not been validated in para-swimmers. The purpose of this study was to validate a single IMU-based system to accurately estimate pool-swam lap time, stroke count (SC), stroke duration, instantaneous stroke rate (ISR), and distance per stroke (DPS). Eight Paralympic athletes completed 4 × 50 m swims with an IMU worn on the sacrum. Strokes cycles were identified using a zero-crossing algorithm on the medio-lateral (freestyle and backstroke) or forward-backward (butterfly and breaststroke) instantaneous velocity data. Video-derived metrics were estimated using Dartfish and Kinovea. Agreement analyses, including Bland-Altman and Intraclass Correlation Coefficient (ICC), were performed on all outcome variables. SC Bland-Altman bias was 0.13 strokes, and ICC was 0.97. ISR Bland-Altman biases were within 1.5 strokes/min, and ICCs ranged from 0.26 to 0.96. DPS Bland-Altman biases were within 0.20 m, and ICCs ranged from 0.39 to 0.93. A single-IMU system can provide highly valid performance and swim stroke monitoring data for elite para-swimmers for the majority of strokes, with the exception of backstroke. Future work should improve bilateral stroke detection algorithms in this population.

Re-assessing the social climate of physical (in)activity in Canada

Social-ecological models suggest that a strategy for increasing population physical activity participation is to reconstruct the "social climate" through changing social norms and beliefs about physical activity (PA). In this study, we assessed whether the PA social climate in Canada has changed over a five-year period after controlling for sociodemographic factors and PA levels. Replicating a survey administered in 2018, a sample of adults in Canada (n = 2,507) completed an online survey assessing social climate dimensions, including but not limited to descriptive and injunctive norms. Descriptive statistics were calculated, and binary logistic regressions were conducted to assess the associations of sociodemographic factors and year of the survey with social climate dimensions. Results suggest some social climate constructs are trending in a positive direction between 2018 and 2023. Physical inactivity was considered a serious public health concern by 49% of respondents, second to unhealthy diets (52%). Compared to those who participated in the 2018 survey, participants in 2023 were less likely to see others walking or wheeling in their neighbourhood (OR = 1.58, 95% CI: 1.41, 1.78), but more likely to see people exercising (OR = 0.82, 95% CI: 0.73, 0.92) and kids playing in their neighbourhood (OR = 0.75, 95% CI: 0.66, 0.85). No changes were reported between 2018 and 2023 in individuals' perceptions of whether physical inactivity is due to individual versus external factors (OR = 0.99, 95% CI: 0.87, 1.13). The findings of this work indicate a modest positive shift in some measured components of the social climate surrounding PA although attributing causes for these changes remain speculative.

Exploring Piezo1, Piezo2, and TMEM150C in human brain tissues and their correlation with brain biomechanical characteristics

Unraveling the intricate relationship between mechanical factors and brain activity is a pivotal endeavor, yet the underlying mechanistic model of signaling pathways in brain mechanotransduction remains enigmatic. To bridge this gap, we introduced an in situ multi-scale platform, through which we delineate comprehensive brain biomechanical traits in white matter (WM), grey-white matter junctions (GW junction), and the pons across human brain tissue from four distinct donors. We investigate the three-dimensional expression patterns of Piezo1, Piezo2, and TMEM150C, while also examining their associated histological features and mechanotransduction signaling networks, particularly focusing on the YAP/β-catenin axis. Our results showed that the biomechanical characteristics (including stiffness, spring term, and equilibrium stress) associated with Piezo1 vary depending on the specific region. Moving beyond Piezo1, our result demonstrated the significant positive correlations between Piezo2 expression and stiffness in the WM. Meanwhile, the expression of Piezo2 and TMEM150C was shown to be correlated to viscoelastic properties in the pons and WM. Given the heterogeneity of brain tissue, we investigated the three-dimensional expression of Piezo1, Piezo2, and TMEM150C. Our results suggested that three mechanosensitive proteins remained consistent across different vertical planes within the tissue sections. Our findings not only establish Piezo1, Piezo2, and TMEM150C as pivotal mechanosensors that regulate the region-specific mechanotransduction activities but also unveil the paradigm connecting brain mechanical properties and mechanotransduction activities and the variations between individuals.

Unsupervised Stereo Matching with Surface Normal Assistance for Indoor Depth Estimation

To obtain more accurate depth information with stereo cameras, various learning-based stereo-matching algorithms have been developed recently. These algorithms, however, are significantly affected by textureless regions in indoor applications. To address this problem, we propose a new deep-neural-network-based data-driven stereo-matching scheme that utilizes the surface normal. The proposed scheme includes a neural network and a two-stage training strategy. The neural network involves a feature-extraction module, a normal-estimation branch, and a disparity-estimation branch. The training processes of the feature-extraction module and the normal-estimation branch are supervised while the training of the disparity-estimation branch is performed unsupervised. Experimental results indicate that the proposed scheme is capable of estimating the surface normal accurately in textureless regions, leading to improvement in the disparity-estimation accuracy and stereo-matching quality in indoor applications involving such textureless regions.

Psilocybin and Eugenol Reduce Inflammation in Human 3D EpiIntestinal Tissue

Inflammation plays a pivotal role in the development and progression of inflammatory bowel disease (IBD), by contributing to tissue damage and exacerbating the immune response. The investigation of serotonin receptor 2A (5-HT2A) ligands and transient receptor potential (TRP) channel ligands is of significant interest due to their potential to modulate key inflammatory pathways, mitigate the pathological effects of inflammation, and offer new avenues for therapeutic interventions in IBD. This study investigates the anti-inflammatory effects of 5-HT2A ligands, including psilocybin, 4-AcO-DMT, and ketanserin, in combination with TRP channel ligands, including capsaicin, curcumin, and eugenol, on the inflammatory response induced by tumor necrosis factor (TNF)-α and interferon (IFN)-γ in human 3D EpiIntestinal tissue. Enzyme-linked immunosorbent assay was used to assess the expression of pro-inflammatory markers TNF-α, IFN-γ, IL-6, IL-8, MCP-1, and GM-CSF. Our results show that psilocybin, 4-AcO-DMT, and eugenol significantly reduce TNF-α and IFN-γ levels, while capsaicin and curcumin decrease these markers to a lesser extent. Psilocybin effectively lowers IL-6 and IL-8 levels, but curcumin, capsaicin, and 4-AcO-DMT have limited effects on these markers. In addition, psilocybin can significantly decrease MCP-1 and GM-CSF levels. While ketanserin lowers IL-6 and GM-CSF levels, there are no effects seen on TNF-α, IFN-γ, IL-8, or MCP-1. Although synergistic effects between 5-HT2A and TRP channel ligands are minimal in this study, the results provide further evidence of the anti-inflammatory effects of psilocybin and eugenol. Further research is needed to understand the mechanisms of action and the feasibility of using these compounds as anti-inflammatory therapies for conditions like IBD.

Endosomal dysfunction contributes to cerebellar deficits in spinocerebellar ataxia type 6

Spinocerebellar ataxia type 6 (SCA6) is a rare disease that is characterized by cerebellar dysfunction. Patients have progressive motor coordination impairment, and postmortem brain tissue reveals degeneration of cerebellar Purkinje cells and a reduced level of cerebellar brain-derived neurotrophic factor (BDNF). However, the pathophysiological changes underlying SCA6 are not fully understood. We carried out RNA-sequencing of cerebellar vermis tissue in a mouse model of SCA6, which revealed widespread dysregulation of genes associated with the endo-lysosomal system. Since disruption to endosomes or lysosomes could contribute to cellular deficits, we examined the endo-lysosomal system in SCA6. We identified alterations in multiple endosomal compartments in the Purkinje cells of SCA6 mice. Early endosomes were enlarged, while the size of the late endosome compartment was reduced. We also found evidence for impaired trafficking of cargo to the lysosomes. As the proper functioning of the endo-lysosomal system is crucial for the sorting and trafficking of signaling molecules, we wondered whether these changes could contribute to previously identified deficits in signaling by BDNF and its receptor tropomyosin kinase B (TrkB) in SCA6. Indeed, we found that the enlarged early endosomes in SCA6 mice accumulated both BDNF and TrkB. Furthermore, TrkB recycling to the cell membrane in recycling endosomes was reduced, and the late endosome transport of BDNF for degradation was impaired. Therefore, mis-trafficking due to aberrant endo-lysosomal transport and function could contribute to SCA6 pathophysiology through alterations to BDNF-TrkB signaling, as well as mishandling of other signaling molecules. Deficits in early endosomes and BDNF localization were rescued by chronic administration of a TrkB agonist, 7,8-dihydroxyflavone, that we have previously shown restores motor coordination and cerebellar TrkB expression. The endo-lysosomal system is thus both a novel locus of pathophysiology in SCA6 and a promising therapeutic target.

Trace Sample Proteome Quantification by Data-Dependent Acquisition without Dynamic Exclusion

Despite continuous technological improvements in sample preparation, mass-spectrometry-based proteomics for trace samples faces the challenges of sensitivity, quantification accuracy, and reproducibility. Herein, we explored the applicability of turboDDA (a method that uses data-dependent acquisition without dynamic exclusion) for quantitative proteomics of trace samples. After systematic optimization of acquisition parameters, we compared the performance of turboDDA with that of data-dependent acquisition with dynamic exclusion (DEDDA). By benchmarking the analysis of trace unlabeled human cell digests, turboDDA showed substantially better sensitivity in comparison with DEDDA, whether for unfractionated or high pH fractionated samples. Furthermore, through designing an iTRAQ-labeled three-proteome model (i.e., tryptic digest of protein lysates from yeast, human, and E. coli) to document the interference effect, we evaluated the quantification interference, accuracy, reproducibility of iTRAQ labeled trace samples, and the impact of PIF (precursor intensity fraction) cutoff for different approaches (turboDDA and DEDDA). The results showed that improved quantification accuracy and reproducibility could be achieved by turboDDA, while a more stringent PIF cutoff resulted in more accurate quantification but less peptide identification for both approaches. Finally, the turboDDA strategy was applied to the differential analysis of limited amounts of human lung cancer cell samples, showing great promise in trace proteomics sample analysis.

Effective Mechanical Properties of Periodic Cellular Solids with Generic Bravais Lattice Symmetry via Asymptotic Homogenization

In this paper, the scope of discrete asymptotic homogenization employing voxel (cartesian) mesh discretization is expanded to estimate high fidelity effective properties of any periodic heterogeneous media with arbitrary Bravais's lattice symmetry, including those with non-orthogonal periodic bases. A framework was developed in Python with a proposed fast-nearest neighbour algorithm to accurately estimate the periodic boundary conditions of the discretized representative volume element of the lattice unit cell. Convergence studies are performed, and numerical errors caused by both voxel meshing and periodic boundary condition approximation processes are discussed in detail. It is found that the numerical error in periodicity approximation is cyclically dependent on the number of divisions performed during the meshing process and, thus, is minimized with a refined voxel mesh. Validation studies are performed by comparing the elastic properties of 2D hexagon lattices with orthogonal and non-orthogonal bases. The developed methodology was also applied to derive the effective properties of several lattice topologies, and variation of their anisotropic macroscopic properties with relative densities is presented as material selection charts.

Primates and disability: Behavioral flexibility and implications for resilience to environmental change

Congenital malformations, conditions, injuries, and illness can lead to long-term physical impairment and disability in nonhuman primates. How individual primates change their behaviors flexibly to compensate for their disabilities can inform our understanding of their resilience and ability to adjust to environmental change. Here, we synthesize the literature on nonhuman primates and disability, addressing the questions: how does disability influence behavior in primates? What insights can we take from the literature to better understand and predict the capacity of primates to modify their behaviors in the face of human-induced environmental change? We conducted a systematic review of the literature on spontaneous physical impairment and disability in captive, free-ranging, and wild primates. We surveyed 2807 articles on Web of Science and Scopus and identified 114 studies that fit our predetermined inclusion criteria. Behavioral plasticity, maternal and conspecific care, and the potential for innovation of novel behaviors allow many primates with disabilities to compensate when faced with challenges that are outside the scope of usual circumstances. We also found that 60% of the publications connected primate physical impairment and disability to human activities, suggesting an entangled relationship among humans, the environment, and primate disability. Disability and physical impairments provide an opportunity to examine how primates modify their behavior when presented with challenging conditions, and their potential resilience to a changing environment.

An unsupervised learning approach to identify immunoglobulin utilization patterns using electronic health records

BACKGROUND

Managing Canada's immunoglobulin (Ig) product resource allocation is challenging due to increasing demand, high expenditure, and global shortages. Detection of groups with high utilization rates can help with resource planning for Ig products. This study aims to uncover utilization subgroups among the Ig recipients using electronic health records (EHRs).

METHODS

The study included all Ig recipients (intravenous or subcutaneous) in Calgary from 2014 to 2020, and their EHR data, including blood inventory, recipient demographics, and laboratory test results, were analyzed. Patient clusters were derived based on patient characteristics and laboratory test data using K-means clustering. Clusters were interpreted using descriptive analyses and visualization techniques.

RESULTS

Among 4112 recipients, six clusters were identified. Clusters 1 and 2 comprised 408 (9.9%) and 1272 (30.9%) patients, respectively, contributing to 62.2% and 27.1% of total Ig utilization. Cluster 3 included 1253 (30.5%) patients, with 86.4% of infusions administered in an inpatient setting. Cluster 4, comprising 1034 (25.1%) patients, had a median age of 4 years, while clusters 2-6 were adults with median ages of 46-60. Cluster 5 had 62 (1.5%) patients, with 77.3% infusions occurring in emergency departments. Cluster 6 contained 83 (2.0%) patients receiving subcutaneous Ig treatments.

CONCLUSION

The results identified data-driven segmentations of patients with high Ig utilization rates and patients with high risk for short-term inpatient use. Our report is the first on EHR data-driven clustering of Ig utilization patterns. The findings hold the potential to inform demand forecasting and resource allocation decisions during shortages of Ig products.

Automated Coronary Artery Tracking with a Voronoi-Based 3D Centerline Extraction Algorithm

Coronary artery disease is one of the leading causes of death worldwide, and medical imaging methods such as coronary artery computed tomography are vitally important in its detection. More recently, various computational approaches have been proposed to automatically extract important artery coronary features (e.g., vessel centerlines, cross-sectional areas along vessel branches, etc.) that may ultimately be able to assist with more accurate and timely diagnoses. The current study therefore validated and benchmarked a recently developed automated 3D centerline extraction method for coronary artery centerline tracking using synthetically segmented coronary artery models based on the widely used Rotterdam Coronary Artery Algorithm Evaluation Framework (RCAAEF) training dataset. Based on standard accuracy metrics and the ground truth centerlines of all 32 coronary vessel branches in the RCAAEF training dataset, this 3D divide and conquer Voronoi diagram method performed exceptionally well, achieving an average overlap accuracy (OV) of 99.97%, overlap until first error (OF) of 100%, overlap of the clinically relevant portion of the vessel (OT) of 99.98%, and an average error distance inside the vessels (AI) of only 0.13 mm. Accuracy was also found to be exceptionally for all four coronary artery sub-types, with average OV values of 99.99% for right coronary arteries, 100% for left anterior descending arteries, 99.96% for left circumflex arteries, and 100% for large side-branch vessels. These results validate that the proposed method can be employed to quickly, accurately, and automatically extract 3D centerlines from segmented coronary arteries, and indicate that it is likely worthy of further exploration given the importance of this topic.

Cucurbit[6]uril Hyperpolarized Chemical Exchange Saturation Transfer Pulse Sequence Parameter Optimization and Detectability Limit Assessment at 3.0T

Molecular imaging is the future of personalized medicine; however, it requires effective contrast agents. Hyperpolarized chemical exchange saturation transfer (HyperCEST) can boost the signal of Hyperpolarized 129 Xe MRI and render it a molecular imaging modality of high efficiency. Cucurbit[6]uril (CB6) has been successfully employed in vivo as a contrast agent for HyperCEST MRI, however its performance in a clinical MRI scanner has yet to be optimized. In this study, MRI pulse sequence parameter optimization was first performed in CB6 solutions in phosphate-buffered saline (PBS), and subsequently in whole sterile citrated bovine blood. The performance of four different depolarization pulse shapes (sinusoidal, 3-lobe sinc (3LS), rectangular (block), and hyperbolic secant (hypsec) was optimized. The detectability limits of CB6 in a clinical 3.0T MRI scanner was assessed using the optimized pulse sequences. The 3LS depolarization pulses performed best, and demonstrated 24 % depletion in a 25 μM solution of CB6 in PBS. It performed similarly in blood. The CB6 detectability limit was found to be 100 μM in citrated bovine blood with a correspondent HyperCEST depletion of 30 % ±9 %. For the first time, the HP 129 Xe HyperCEST effect was observed in red blood cells (RBC) and had a similar strength as HyperCEST in plasma.

Is Academic Agency Relevant for the School-to-Work Transition of Lower Attainers? Evidence from Canada and England

Academic agency is recognized as an important predictor of higher education attainment among the general population during the school-to-work transition. However, there is little evidence on whether (a) academic agency is associated with higher education attainment among young people facing education difficulties (i.e., lower attainers), (b) academic agency is associated with a smooth entry in a meaningful job among lower attainers, and (c) these associations vary across educational contexts. This study draws on longitudinal data from lower attainers in the province of Québec (Mage = 16.31, SD = 0.98; 48% females) and in England (Mage = 15.86, SD = 0.72; 42% females), two regions with similar education systems, yet different vocational training provision. In both samples, fewer than one in four participants reach higher education by age 20. Also, in both countries academic agency is associated with a greater likelihood of being in higher education compared to other employment and education outcomes at age 20, but not with rapid entry into meaningful employment. Thus, focussing on higher education attainment and academic-related factors such as academic agency is of limited relevance for understanding lower attainers' success over school-to work transitions. For them, understanding this transition also requires considering rapid entry in meaningful employment, as well as non-academic forms of agency supporting such work-oriented outcomes.

Not just range limits: Warming rate and thermal sensitivity shape climate change vulnerability in a species range center

Climate change manifests unevenly across space and time and produces complex patterns of stress for ecological systems. Species can also show substantial among-population variability in response to environmental change across their geographic range due to evolutionary processes. Explanatory factors or their proxies, such as temperature and latitude, help parse these sources of environmental and intraspecific variability; however, overemphasizing latitudinal trends can obscure the role of local environmental conditions in shaping population vulnerability to climate change. Focusing on the geographic center of a species range to disentangle latitude, we test the hypothesis that populations from warmer regions of a species range are more vulnerable to ocean warming. We conducted a mesocosm experiment and field reciprocal transplant with four populations of a marine snail, Nucella lamellosa, from two regions in British Columbia, Canada, that differ in thermal characteristics: the Central Coast, a cool region, and the Strait of Georgia, one of the warmest regions of this species' range and one that is warming faster than the Central Coast. Populations from the Strait of Georgia experienced growth reductions at contemporary summertime seawater temperatures in the laboratory and showed stark reductions in survival and growth under future seawater conditions and when outplanted at their native transplant sites. This indicates a high vulnerability to ocean warming, especially given the faster rate of ocean warming in this region. In contrast, populations from the cooler Central Coast demonstrated high performance at contemporary seawater temperatures and high growth and survival in projected future seawater temperatures and at their native outplant sites. Given their position within the geographic center of N. lamellosa's range, extirpation events in the vulnerable Strait of Georgia populations could compromise connectivity within the metapopulation and lead to gaps across this species' range. Overall, our study supports predictions that populations from warm regions of species ranges are more vulnerable to environmental warming, suggests that the Strait of Georgia and other inland or coastal seas could be focal points for climate change effects and ecological transformation, and emphasizes the importance of analyzing climate change vulnerability in the context of regional environmental data and throughout a species' range.