McMaster University
  • Hamilton, Ontario, Canada
Recent publications
Advancements in Microelectromechanical systems (MEMS) have enabled the manufacture of affordable and efficient wearable devices. In sensor-based gait analysis, motion and biofeedback sensor devices are easily attached to different parts of the body. Instrumentation of gait using different sensor technologies enables researchers and clinicians to capture high-resolution quantitative motion data within and beyond the lab. Integration of advanced sensor technologies provides objective and rater-independent multimodal outcomes that complement established clinical examination. Multi-modal data capture in ecologically valid, patient-relevant habitual settings opens new possibilities to monitor fluctuating and rare incidents by informing different aspects of impaired gait. Interconnected device communication and the Internet of Things (IoT) provide the infrastructural platform to enable remote gait assessment. However, an extended period of motion data recorded by different sensor technologies results in a vast amount of unlabelled data. Computational methods and artificial intelligence techniques (e.g., data mining) provide opportunities to manage data collected in unsupervised environments. Although technological advancement and algorithms promote remote gait assessment, more work needs to be done in terms of analytical and clinical validation to achieve robust and reliable gait analysis tools that contribute to better rehabilitation and treatment.
Background Some studies suggest that patients with pulmonary hypertension (PH) may be at higher risk of complications and death after noncardiac surgery. However, the magnitude of these associations is unclear. Objectives To determine the associations between PH and adverse outcomes after noncardiac surgery. Methods We searched PUBMED and EMBASE for studies published from January 1970 to April 2022. We included studies that reported the association between PH and one or more outcomes of interest occurring after noncardiac surgery. Data were pooled using random-effects models and reported as summary odds ratios (ORs) with 95% confidence intervals (CIs). Results Eighteen studies met eligibility criteria (n=18,214,760). PH was independently associated with mortality (adjusted odds ratio [OR] 2.09; 95% CI, 1.51-2.90; I²=98%; 8 studies). PH was associated with a higher unadjusted risk of deep venous thrombosis (OR 4.02; 95% CI, 2.14-7.54; I²=85%; 3 studies), pulmonary embolism (OR 4.16; 95% CI, 3.23-5.36; I²=69%; 7 studies), myocardial infarction (OR 1.49; 95% CI, 1.44-1.54; I²=0%; 5 studies), congestive heart failure or cardiogenic shock (OR 3.37; 95% CI, 1.73–6.60; I²=34%; 5 studies), length of hospital stay (mean difference 1.97 days; 95% CI, 0.81–3.12; I²=99%; 5 studies), and delayed extubation (OR 5.98; 95% CI, 1.70–21.02; I²=3%; 3 studies). PH was associated with lower unadjusted risk of postoperative stroke (OR 0.93; 95% CI, 0.88–0.98; I²=0%; 3 studies). Conclusion PH is a predictor of morbidity and mortality after noncardiac surgery. High quality studies are needed to determine effective strategies for reducing postoperative complications in this population.
The potential of MRI to predict cartilage mechanical properties across an entire cartilage surface in an ex vivo model would enable novel perspectives in modeling cartilage tolerance and predicting disease progression. The purpose of this study was to integrate MR imaging with full-surface indentation mapping to determine the relationship between femoral cartilage thickness and T2 relaxation change following loading, and cartilage mechanical properties in an ex vivo porcine stifle model. Matched-pairs of stifle joints from the same pig were randomized into either 1) an imaging protocol where stifles were imaged at baseline and after 35 min of static axial loading; and 2) full surface mapping of the instantaneous modulus (IM) and an electromechanical property named quantitative parameter (QP). The femur and femoral cartilage were segmented from baseline and post-intervention scans, then meshes were generated. Coordinate locations of the indentation mapping points were rigidly registered to the femur. Multiple linear regressions were performed at each voxel testing the relationship between cartilage outcomes (thickness change, T2 change) and mechanical properties (IM, QP) after accounting for covariates. Statistical Parametric Mapping was used to determine significance of clusters. No significant clusters were identified; however, this integrative method shows promise for future work in ex vivo modeling by identifying spatial relationships among variables.
Background Pancreatic cancer is the third leading cause of cancer death in the United States, which is attributed to limited treatment options. Complementary and alternative medicine (CAM) therapies have been proposed to provide benefits in treating pancreatic cancer. Despite its importance in treatment, clinicians are not generally well equipped to counsel their patients about CAM therapies. This review identified the quantity and assessed the quality of clinical practice guidelines (CPGs) providing CAM recommendations for the treatment and/or management of pancreatic cancer. Methods A systematic review was conducted to identify pancreatic cancer CPGs. MEDLINE, EMBASE and CINAHL were searched from 2011 to 2022. The Guidelines International Network (GIN) and the National Center for Complementary and Integrative Health (NCCIH) websites were also searched. Eligible CPGs published by non-profit agencies on treatment and/or management of pancreatic cancer for adults were assessed using the Appraisal of Guidelines, Research and Evaluation II (AGREE II) instrument. Results From 31 eligible search results, 7 CPGs mentioned CAM and 3 CPGs made CAM recommendations. The mean scaled domain percentages of the CPGs in this study (overall, CAM-specific) were as follows: scope and purpose (81.3%, 77.8%), stakeholder involvement (63.9%, 42.6%), rigor-of-development (51.0%, 40.3%), clarity-of-presentation (83.3%, 54.6%), applicability (42.3%, 30.5%), and editorial independence (58.3%, 58.3%). Conclusions Evaluation of the CPGs demonstrated that quality varied both within and between CPGs. CPGs that scored well could be used by patients and clinicians as the basis for discussion for the use of CAM therapies. Future research should identify other appropriate CAM therapies for further development of CPGs for pancreatic cancer. Registration The protocol was registered on PROSPERO (registration number: CRD42022334025).
Acoustic sensing has attracted significant attention recently, thanks to the pervasive availability of device support. However, adopting consumer-grade devices (e.g., smartphones) to deploy acoustic sensing applications faces the challenge of device/OS heterogeneity. Researchers have to pay tremendous efforts in tackling platform-dependent details even in simply accessing raw audio samples, thus losing focus on innovating sensing algorithms. To this end, this paper presents the first Acoustic Software Defined Platform (ASDP): a versatile sensing and general benchmarking platform. ASDP encompasses several customized acoustic modules running on a ubiquitous computing board, backed by a dedicated software framework. It is superior to commodity devices in controlling and reconfiguring physical layer settings, thus offering much better usability. The tailored software framework abstracts platform details and provides user-friendly interface for fast prototyping, while maintaining adequate programmability. To demonstrate the usefulness of ASDP, we showcase several relevant applications based on it. The promising outcomes make us believe that the release of our ASDP could greatly advance acoustic sensing research.
Individuals differ in the extent to which they believe that their emotions are controllable or not, and these beliefs have significant impacts on emotional functioning. A strong belief that your emotions are uncontrollable (fixed mindset) is a vulnerability for emotional dysfunction, such as internalizing symptoms; however, the proximal mechanisms that might explain how emotional beliefs manifest as symptoms remain unclear. Across two studies, we examined whether mindset was indirectly related to internalizing symptoms through use of avoidance-based strategies and whether perceptions of stress function to amplify this relationship. In Study 1, (N = 163; mean age = 17.9), a fixed mindset was associated with a greater presence of depression and anxiety symptoms in undergraduates indirectly through the use of avoidance for anxiety, but not depression. Perceived stress did not moderate the indirect effect. In Study 2 (N = 183; mean age = 18.74) we replicated this model and extended this finding by examining social-avoidance. There was an indirect effect of mindset on anxiety and on depression via the use of avoidance-based strategies; however, there was no moderating effect of perceived stress. These findings extend the previous literature by demonstrating for role of avoidance in understanding the relationship between fixed mindsets and internalizing symptoms.
The purpose of this study is to improve the quality of the multi-track laser cladding coating. The Taguchi-Grey relation method was selected to realize process parameter optimization. The Taguchi method is used to design an L16 orthogonal experiment. The influence of three important laser cladding parameters (laser power, powder feeding rate, and scanning speed) on the micro-hardness, maximum load value, yield strength, UTS, and elongation had been analyzed based on the analysis of variance (ANOVA) and signal to noise ratio (SNR) methods. The results showed that the yield strength, UTS, and elongation were significantly affected by the laser power; the powder feeding rate denoted a highly significant influence on the microhardness and yield strength; and the scanning speed was a highly significant factor that had an influence on the maximum load value. Then, grey relational analysis (GRA) was used to convert five response targets into a single grey relational grade (GRG) that could be quantified in order to optimize the parameters for maximum micro-hardness, maximum load value, yield strength, UTS, and elongation. Finally, the optimum cladding process parameters were obtained. Through analysis of microstructure, the reduction of the Laves phase might be the main reason for the improvement of coating performance after optimization.
Background Collecting duct carcinoma (CDC) is biologically more aggressive than clear cell renal cell carcinoma (ccRCC). We tested for differences in cancer specific mortality (CSM) rates according to CDC vs. ISUP (International Society of Urological Pathology) 4 ccRCC histological subtype. We hypothesized that the survival disadvantage still applies, even after most detailed adjustments. Methods Within Surveillance, Epidemiology, and End Results database (2004–2018), we identified 380 CDC vs. 6273 ISUP 4 ccRCC patients of all stages. Propensity score matching (age, sex, race/ethnicity, T, N, and M stages, nephrectomy, and systemic therapy status), Kaplan-Meier plots and multivariable Cox regression models were used. Results All 380 CDC were matched (1:2) with 760 ISUP4 ccRCC patients. Prior to matching CDC patients exhibited higher rates of lymph node invasion (37.6 % vs. 14.7 %, p < 0.001), and of distant metastases (40.8 % vs. 30.4 %, p < 0.001). Systemic therapy rates were higher in CDC (29.5 % vs. 20.5 %, p < 0.001). However, nephrectomy rates were higher in ISUP4 ccRCC patients (97.5 % vs. 84.7 %, p < 0.001). After matching, in multivariable Cox regression models addressing CSM, CDC was associated with a HR of 1.5 (p < 0.001) in the overall population vs. 1.9 (p = 0.014) in stage I-II vs. 1.4 (p = 0.022) in stage III vs. 1.6 in stage IV (p < 0.001), relative to ISUP4 ccRCC. Conclusion CDC patients exhibited 40–90 % higher CSM than their ISUP4 ccRCC counterparts in the overall analysis, as well as in stage specific analyses. The CSM disadvantage applies despite higher rates of systemic therapy in CDC patients.
Much research suggests democracies invest more in human capital formation than dictatorships. In particular, scholars have suggested that democracies outspend autocracies on education, due to electoral and interest group pressures. However, some democracies spend no more on education - and some spend much less - than autocracies. What explains this variation within democracies? The answer is the influence of landed agricultural elites. Urban industrial elites support human capital investment because it leads to higher rates of return even if wages increase. Yet greater education spending encourages out-migration from the countryside, reducing the supply and increasing the price of agricultural labor. Given the differential impact of education spending across economic sectors, the effect of democracy on education spending may be conditional on the power of landed elites. We test this argument in two ways. First, we run a series of time series cross-sectional regressions on data from 107 countries for the period 1970 to 2000. Second, we conduct a difference-in-difference analysis, comparing countries that democratize at high versus low levels of land inequality, for 73 countries for the same time period. Results confirm a negative relationship between the power of landed elites and investment in public education under democracy, adding important and novel insight into the sources of differences in public-goods spending and human capital investment both within across political regimes.
Aim Some studies have reported that children with poor motor functioning tend to improve over time. However, much existing research does not account for regression towards the mean (RTM). Here, we examine measurement stability among 589 children aged 4–5 years. Method We administered the Movement Assessment Battery for Children 2nd Edition annually to 269 children initially scoring above and 252 at or below the 16th percentile. We measured agreement between year 1 and year 2 standard scores using Pearson correlation and derived expected regression towards the mean (RTM). We then regressed follow-up on baseline scores, controlling for relative age, sex, and exact interval between assessments. Finally, we performed a small illustrative simulation. Outcomes and results The mean score in the poor-coordination group rose from 5.6 (SD = 1.5) to 7.2 (SD = 2.8). Year 1 and year 2 scores were correlated at r = 0.66, corresponding to predicted RTM in the MI group of 1.56, close to the observed change of 1.57. Degree of change was not associated with time between assessments. Interpretation Observed improvements in motor functioning were consistent with measurement error. The stability of motor functioning may be greater than it appears from past research, and reported functional improvements in some studies may be illusory. What this paper adds? -Impaired motor coordination is common and can meaningfully affect functioning. -Our analysis suggests that coordination is generally stable. -Apparent improvement in research may often be produced by measurement error.
The inclusion of microencapsulated phase change materials (MPCM) in construction materials is a promising solution for increasing the energy efficiency of buildings and reducing their carbon emissions. Although MPCMs provide thermal energy storage capability in concrete, they typically decrease its compressive strength. A unified framework for the mixture design of concrete incorporating MPCM is yet to be developed to facilitate practical applications. This study proposes a mix design procedure using a novel ternary machine learning (ML) paradigm. For this purpose, the tabular generative adversarial network (TGAN) was utilized to generate large synthetic mixture design data based on the limited available experimental observations. The synthetic data is then employed to construct robust predictive ML models. The gradient boosting regressor (GBR) model trained with synthetic data outperformed the model trained with real data, achieving a testing coefficient of determination (R 2) of 0.963 and mean absolute error (MAE) of 2.085 MPa. The TGAN-GBR model was ultimately integrated with the particle swarm optimization (PSO) algorithm to construct a powerful recommendation system for optimizing the mixture design of concrete and mortar incorporating different types of MPCMs. Extensive parametric analyses along with the employed optimization procedure accomplished the mixture design of latent heat thermal energy storage concrete with maximum MPCM inclusion and minimum cement content for various compressive strength classes. The proposed framework enables energy conservation technology in the design of eco-friendly building materials with acceptable mechanical performance.
In patients with non–ST-elevation myocardial infarction (NSTEMI), total occlusion of the culprit coronary artery (OCA) is not uncommon. We sought to determine the frequency and clinical impact of OCA at presentation in a large population of patients presenting with NSTEMI and who underwent systematic early invasive management. We performed a post hoc analysis of the TAO (Treatment of Acute Coronary Syndrome with Otamixaban) randomized trial, which included patients with NSTEMI with systematic coronary angiography within 72 hours. We compared the baseline characteristics and outcomes of patients according to whether the culprit vessel was occluded (thrombolysis in myocardial infarction flow grade [TFG] 0 to 1) or patent (TFG 2 to 3) at presentation. A total of 7,473 patients with NSTEMI with only 1 culprit lesion identified were enrolled, of whom 1,702 patients had OCA (22.8%). In the OCA group, coronary angiography was performed earlier (18 ± 15 vs 20 ± 16 hours, p <0.01), the culprit lesion was less likely to be the left anterior descending artery (26.5% vs 41.4%, p <0.001) but with more frequent angiographic thrombus (49.9% vs 22.7%, p <0.01). Culprit artery percutaneous coronary intervention during the index procedure was also more frequent (88.5% vs 78.1%, p <0.001) but with a lower rate of TFG grade 3 after the procedure and higher subsequent peak troponin I levels (8.3 ± 13.6 µg/L vs 5.6 ± 11.9 µg/L, p <0.001). At day 7, patients with OCA had higher mortality, and this persisted after adjustment on gender, Grace risk score, cardiovascular risk factors, and culprit vessel location (0.9% vs 0.4%, p = 0.02; adjusted odds ratio [OR] = 2.55, 95% confidence interval [CI] 1.23 to 5.29, p = 0.01). The absolute difference of mortality was maintained through 30 days: 1.2% versus 0.8%, p = 0.13; OR: 1.72, 95% CI 0.97 to 3.05, but mortality rates were similar by 180 days: 1.5% versus 1.6%, p = 0.8, adjusted OR = 1.11, 95% CI 0.69 to 1.80, p = 0.66. In conclusion, a significant proportion of patients with NSTEMI have a totally occluded culprit vessel at presentation. These patients are at higher risk of early mortality but not at 6 months.
Context Outcomes in renal cell carcinoma (RCC) are reported inconsistently, with variability in definitions and measurement. Hence, it is difficult to compare intervention effectiveness and synthesise outcomes for systematic reviews and to create clinical practice guidelines. This uncertainty in the evidence makes it difficult to guide patient-clinician decision-making. One solution is a core outcome set (COS): an agreed minimum set of outcomes. Objective To describe outcome reporting, definitions, and measurement heterogeneity as the first stage in co-creating a COS for localised renal cancer. Evidence acquisition We systematically reviewed outcome reporting heterogeneity in effectiveness trials and observational studies in localised RCC. In total, 2822 studies (randomised controlled trials, cohort studies, case-control studies, systematic reviews) up to June 2020 meeting our inclusion criteria were identified. Abstracts and full texts were screened independently by two reviewers; in cases of disagreement, a third reviewer arbitrated. Data extractions were double-checked. Evidence synthesis We included 149 studies and found that there was inconsistency in which outcomes were reported across studies and variability in the definitions used for outcomes that were conceptually the same. We structured our analysis using the outcome classification taxonomy proposed by Dodd et al. Outcomes linked to adverse events (eg, bleeding, outcomes linked to surgery) and renal injury outcomes (reduced renal function) were reported most commonly. Outcomes related to deaths from any cause and from cancer were reported in 44% and 25% of studies, respectively, although the time point for measurement and the analysis methods were inconsistent. Outcomes linked to life impact (eg, global quality of life) were reported least often. Clinician-reported outcomes are more frequently reported than patient-reported outcomes in the renal cancer literature. Conclusions This systematic review underscores the heterogeneity of outcome reporting, definitions, and measurement in research on localised renal cancer. It catalogues the variety of outcomes and serves as a first step towards the development of a COS for localised renal cancer. Patient summary We reviewed studies on localised kidney cancer and found that multiple terms and definitions have been used to describe outcomes. These are not defined consistently, and often not defined at all. Our review is the first phase in developing a core outcome set to allow better comparisons of studies to improve medical care.
Objectives: We set out to determine the accuracy of the interRAI Emergency Department (ED) Screener in predicting the need for detailed geriatric assessment in the ED. Our secondary objective was to determine the discriminative ability of the interRAI ED Screener for predicting the odds of discharge home and extended ED length of stay (>24 hours). Methods: We conducted a multiprovince prospective cohort study in Canada. The need for detailed geriatric assessment was determined using the interRAI ED Screener and the interRAI ED Contact Assessment as the reference standard. A score of ≥5 was used to classify high-risk patients. Assessments were conducted by emergency and research nurses. We calculated the sensitivity, positive predictive value, and false discovery rate of the interRAI ED Screener. We employed logistic regression to predict ED outcomes while adjusting for age, sex, academic status, and the province of care. Results: A total of 5629 older ED patients across 11 ED sites were evaluated using the interRAI ED Screener and 1061 were evaluated with the interRAI ED Contact Assessment. Approximately one-third of patients were discharged home or experienced an extended ED length of stay. The interRAI ED Screener had a sensitivity of 93%, a positive predictive value of 82%, and a false discovery rate of 18%. The interRAI ED Screener predicted discharge home and extended ED length of stay with fair accuracy. Conclusion: The interRAI ED Screener is able to accurately and rapidly identify individuals with medical complexity. The interRAI ED Screener predicts patient-important health outcomes in older ED patients, highlighting its value for vulnerability screening.
Mathematical optimization can be a useful strategy for minimizing energy usage while designing low-energy buildings. To handle building energy optimization challenges, this study provides an effective hybrid technique based on the pelican optimization algorithm (POA) and the single candidate optimizer (SCO). The suggested hybrid algorithm (POSCO) benefits from both the robust local search power of the single candidate method and the efficient global search capabilities of the pelican optimization. To conduct the building optimization task, the optimization method was developed and integrated with the EnergyPlus codes. The effectiveness of the proposed POSCO method was verified using mathematical test functions, and the outcomes were contrasted with those of conventional POA and other effective optimization techniques. Application of POSCO for global function optimization reveals that, among the thirteen considered functions, the proposed method was best at finding the global solution for seven functions, while providing superior results for the other functions when compared with competitive techniques. The suggested POSCO is applied for reducing an office buildings' annual energy use. Comparing POSCO to POA procedures, the building energy usage is reduced. Furthermore, POSCO is compared to simple POA and other algorithms, with the results showing that, at specific temperatures and lighting conditions, the POSCO approach outperforms selected state-of-the-art methods and reduces building energy usage. As a result, all data suggests that POSCO is a very promising, dependable, and feasible optimization strategy for dealing with building energy optimization models. Finally, the building energy optimization findings for various climatic conditions demonstrate that the changes to the weather dataset had limited effect on the efficiency of the optimization procedure.
The Cox proportional hazards model is commonly used in evaluating risk factors in cancer survival data. The model assumes an additive, linear relationship between the risk factors and the log hazard. However, this assumption may be too simplistic. Further, failure to take time-varying covariates into account, if present, may lower prediction accuracy. In this retrospective, population-based, prognostic study of data from patients diagnosed with cancer from 2008 to 2015 in Ontario, Canada, we applied machine learning-based time-to-event prediction methods and compared their predictive performance in two sets of analyses: (1) yearly-cohort-based time-invariant and (2) fully time-varying covariates analysis. Machine learning-based methods—gradient boosting model (gbm), random survival forest (rsf), elastic net (enet), lasso and ridge—were compared to the traditional Cox proportional hazards (coxph) model and the prior study which used the yearly-cohort-based time-invariant analysis. Using Harrell’s C index as our primary measure, we found that using both machine learning techniques and incorporating time-dependent covariates can improve predictive performance. Gradient boosting machine showed the best performance on test data in both time-invariant and time-varying covariates analysis.
With the increasing number of options for the treatment of moderate‐to‐severe atopic dermatitis, clinicians need guidance on a practical approach to selecting a systemic agent for specific patient populations. We convened an expert panel consisting of 12 members to conduct a literature review and summarize relevant data related to six scenarios of clinical interest: comorbid asthma, ocular surface disease, history of cancer, past and ongoing infections of interest (including herpes simplex virus, herpes zoster, hepatitis B, and tuberculosis), pregnancy and lactation, and the elderly. We performed a literature search and examined each clinical scenario with respect to three major categories of available systemic agents: traditional systemics (azathioprine, cyclosporine A, methotrexate, and mycophenolate mofetil), Janus kinase inhibitors (abrocitinib, baricitinib, and upadacitinib), and biologics (dupilumab, lebrikizumab, and tralokinumab). The expert panel and steering committee met virtually to review the data and discuss the drafted consensus statements. A modified Delphi process was used to arrive at a set of final consensus statements related to the systemic treatment of AD in these specific patient populations. To provide practical guidance on the choice of systemic therapy for atopic dermatitis in these six topics of clinical interest, 25 expert consensus statements and a summary of the supporting data are presented herein.
White matter (WM) injury is frequently observed along with dementia. Positron emission tomography with amyloid-ligands (Aβ-PET) recently gained interest for detecting WM injury. Yet, little is understood about the origin of the altered Aβ-PET signal in WM regions. Here, we investigated the relative contributions of diffusion MRI-based microstructural alterations, including free water and tissue-specific properties, to Aβ-PET in WM and to cognition. We included a unique cohort of 115 participants covering the spectrum of low-to-severe white matter hyperintensity (WMH) burden and cognitively normal to dementia. We applied a bi-tensor diffusion-MRI model that differentiates between (i) the extracellular WM compartment (represented via free water), and (ii) the fiber-specific compartment (via free water-adjusted fractional anisotropy [FA]). We observed that, in regions of WMH, a decrease in Aβ-PET related most closely to higher free water and higher WMH volume. In contrast, in normal-appearing WM, an increase in Aβ-PET related more closely to higher cortical Aβ (together with lower free water-adjusted FA). In relation to cognitive impairment, we observed a closer relationship with higher free water than with either free water-adjusted FA or WM PET. Our findings support free water and Aβ-PET as markers of WM abnormalities in patients with mixed dementia, and contribute to a better understanding of processes giving rise to the WM PET signal.
Comb polymers were prepared by reacting a poly(ethylene‐alt‐maleic anhydride) with alkyl amines or PEG amines. The resulting polymers were used to modify bleached softwood kraft pulp fiber surfaces by catalyst‐free grafting in a process suitable for pulp mill implementation. Pulp fibers were impregnated with a polymer solution and cured above 100 oC. High grafting yields were obtained despite having up to 88% of the anhydride groups consumed by amine derivatization. Grafting yields were more than 90% when the polymer dosage was <13 g/kg (dry polymer/dry fiber) for alkyl derivatives and <38 g/kg for PEG derivatives. We propose that the upper dosage limit for efficient grafting reflects the need for direct contact between cellulose and every polymer chain for ester linkage formation. For a given polymer dosage, the cured pulp sheets had a maximum wet tensile index, TImax, when either curing time or temperature was increased. Both the alkyl and PEG derivatives fit the power law for the wet TImax~βΓru0.54‐0.62 where β values were the estimated conversion of succinic acid moieties to anhydrides when the pulp sheets were cured, and Γru is the dimensionless polymer content that is numerically equal to the amount of applied polymer in mmol repeat units/g dry fiber. However, high polymer dosages give experimental TImax values that fall below the power law, irrespective of curing intensity, because the pulp sheets contain unfixed polymer chains that lubricate fiber/fiber joints, lowering wet strength. This article is protected by copyright. All rights reserved.
The subsynovial connective tissue is an integral component of flexor tendon gliding in the carpal tunnel, which is strained during longitudinal tendon displacement. We tested the effects of repetition frequency and finger load on flexor tendon function throughout active finger movement. Eleven participants performed metacarpophalangeal joint flexion/extension of the long finger cyclically at three repetition frequencies (0.75, 1.00, 1.25 Hz) and two finger loads (3.5, 7 N). Relative displacement between the flexor digitorum superficialis tendon and subsynovial connective tissue was assessed as the shear‐strain index with colour ultrasound throughout the entire time history of finger flexion and extension. In addition, long finger joint angles were measured with electrogoniometry while flexor digitorum superficialis and extensor digitorum muscle activities were measured with fine‐wire electromyography to characterize the finger movements. The shear‐strain index increased with greater finger flexion (p=0.001), representing higher relative displacement between tendon and subsynovial connective tissue; however, no changes were observed throughout finger extension. The shear‐strain index also increased with higher repetition frequencies (p=0.013) and finger loads (p=0.029), further modulating time dependent effects during finger flexion versus extension. Using ultrasound, we characterized the time dependent response of the shear‐strain index, in vivo, providing valuable data on flexor tendon function during active finger movement. Our results infer greater subsynovial connective tissue strain and shear during repetitive and forceful finger movements. Future research characterizing time dependent effects in carpal tunnel syndrome patients may further elucidate the relations between subsynovial connective tissue function, damage, and carpal tunnel syndrome. This article is protected by copyright. All rights reserved.
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18,066 members
Behnam Sadeghirad
  • Departments of Anethesia and Clinical Epidemiology & Biostatistics
Omar M. Bdair
  • Department of Mathematics and Statistics
Matiar Howlader
  • Department of Electrical and Computer Engineering
Carlos Alberto Cuello-Garcia
  • Health Research Methods Evidence and Impact
Loubna Akhabir
  • Department of Medicine
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