Matched-pair Design Research Articles

Optimization of High-Frequency Ultrasound Imaging to Detect Incremental Changes in Mineral Content at the Cartilage–Bone Interface Ex Vivo

(1) Background: Osteoarthritis is a degenerative disease of the whole joint marked by cartilage–bone interface (CBI) remodeling, but methods to monitor subtle changes in mineralization are lacking. We optimized a non-destructive ultrasound imaging method to monitor incremental shifts in mineralization, using brief decalcification as a mimetic of CBI remodeling. (2) Methods: We used a 35-MHz transducer to scan 3 mm diameter bovine osteochondral explants wrapped with parafilm to produce surface-directed decalcification and dedicated 3D-printed holders to maintain sample orientation. Customized MATLAB codes and a matched pair design were used for quantitative hypothesis testing. (3) Results: Optimal scan precision was obtained when the High-Frequency Ultrasound (HFUS) focal distance was trained at the CBI. HFUS cartilage thickness increased by 53 ± 21 µm or 97 ± 28 µm after three or seven hours of ethylene diamine tetra-acetic acid (EDTA) (but not PBS), respectively, and was highly correlated with histological cartilage thickness (R = 0.98). The en face CBI backscatter pattern was irregular and shifted after the EDTA-displacement of the mineral front. Collective data suggested that the −10 dB echogenic CBI signal originated from the mineral front and varied topographically with undulating mineral thickness. (4) Conclusions: This imaging approach could be used to monitor tidemark remodeling in live explant cultures, toward identifying new treatments that inhibit tidemark advancement and slow osteoarthritis progression.

A pilot investigation on inflammatory markers and theta burst stimulation protocol interaction along a three-month recovery course following an isolated upper limb fracture.

This study investigates the effects of theta burst stimulation (TBS) on inflammatory markers in patients with isolated upper limb fractures (IULF). Participants underwent a 10-day TBS intervention following a randomized matched pair design. Blood samples collected at three time points were analyzed for inflammatory biomarkers, mainly including interleukin-1 receptor antagonist (IL-1Ra), IL-1β, and IL-6. Results revealed a significant interaction between TBS and time for IL-1Ra, indicating a more pronounced decrease in IL-1Ra expression over time in the active TBS group. However, IL-6 levels decreased over time regardless of TBS intervention, suggesting a natural decline in response to injury. No significant interaction was found for IL-1β. While IL-1Ra levels were associated with higher functional disability prior to treatment initiation, active TBS intervention led to a decrease of IL-1Ra levels at both follow-up time points. These changes were not associated with alterations in pain or disability, suggesting that TBS may primarily influence recovery processes independent of pain modulation. Notably, IL-1β levels were negatively correlated with disability in the active TBS group at the 3-month follow-up. This study sheds light on the potential of TBS to modulate inflammatory responses in orthopedic trauma, emphasizing the need for further research to elucidate its therapeutic implications. Clinical Significance: TBS may offer a promising adjunctive therapy for promoting functional recovery in patients with upper limb fractures.

The influence of parental burnout on middle school students' academic achievement: moderated mediation effect.

This study investigates the influence of parental burnout on the academic achievement of middle school students, as well as the mediating role of academic self-efficacy and the moderating role of middle school students' gender and parental gender. Utilizing a parent-child matched-pair design, a questionnaire survey was conducted with 738 middle school students and their parents (either fathers or mothers). The findings revealed that: (1) parental burnout significantly and negatively predicted middle school students' academic achievement; (2) academic self-efficacy partially mediated the relationship between parental burnout and middle school students' academic achievement; and (3) the gender of middle school students moderated the initial segment of this mediating effect, while parental gender did not significantly moderate the relationship, indicating that the significant negative predictive effect of parental burnout on academic self-efficacy was evident only among female middle students. These results not only enhance our understanding of the mechanisms and conditions under which parental burnout impacts middle school students' academic achievement, but also have important implications for improving middle school students' academic self-efficacy and overall academic performance.

Sample Size Estimation for Correlated Count Data With Changes in Dispersion.

Clinical endpoints based on repeated measurements arise in many clinical research studies, and require specialized methods for sample size and power calculations. In clinical trials that measure counts over time, such as bleeding events in hemophilia, the dispersion of their distributions might change upon treatment and the measurements might be correlated. The generalized estimating equations (GEE) approach has been widely used for modeling correlated data and comparing rates. In this paper, we investigate the properties of GEE when applied to count outcomes with changes in dispersion. We derive general closed-form formulas to estimate sample size when the dispersion parameters and distributions of count data vary across two correlated measurements based on the GEE approach. These formulas allow for power and sample size estimation for intra-participant comparison of rates before and after an intervention, randomized controlled trials with equal allocation, or matched pairs designs. These formulas are derived for the following distributions: Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial distributions, and do not assume that measurements before and after an intervention come from the same distribution. Furthermore, we propose modified methods for estimating sample size and confidence intervals for the negative binomial distributions to overcome Type I error inflation, which is especially useful for large changes in the negative binomial dispersion parameter. We perform simulations, and evaluate the performance of the empirical power and Type I error over a range of parameters. Applications and R functions implementing the methods are also provided.

Enhancement of Interferon-γ Secretion by Lepidium meyenii Extract Supplementation After Exhaustive Endurance Exercise in Healthy Men: A Double-blind, Placebo-controlled Trial.

Aim: To investigate the effects of 12-week Lepidium Meyenii extract supplementation on immune responses and inflammatory cytokines after exhaustive endurance exercise (EEE), emphasizing its novel focus on peripheral blood mononuclear cells (PBMCs) cytokine secretion and the implications of interferon-γ (IFN-γ) as a marker for immune modulation. Methods: Twenty healthy men were recruited and assigned into maca and placebo groups using a matched-pair design based on their maximal oxygen consumption (V̇O2max). All participants consumed 2.25 g of maca or placebo twice per day for 12 weeks, and they then performed EEE. Researchers collected blood samples before exercise, immediately after exercise, and at 2, 4, and 24 hours post-exercise to analyze immune functions and inflammatory markers. Results: No significant differences were observed in the variables between the two groups before supplementation. However, interferon-γ levels from peripheral blood mononuclear cells were significantly higher in the maca group than in the placebo group immediately and at 24 hours after exercise. Regarding the main time effect, the number of lymphocytes in all participants was significantly lower at 2 and 4 hours after exercise than before supplementation. The CD4+/CD8+ ratio in the groups was significantly lower immediately after exercise than before supplementation, and the ratio retuned to baseline levels at 2 hours after exercise. Conclusion: A 60-minute EEE session induces the open window phenomenon, characterized by immune suppression. Moreover, 12-week maca supplementation had positive effects only on interferon-γ levels from peripheral blood mononuclear cells.

Give it your all or hardly give? The role of mentors' beliefs about protégé advancement potential and gender in mentoring relationships

Our research challenges assumptions about equity in formal mentoring programs. Drawing on mentoring schema and diversified mentoring theory, we theorized that mentors' beliefs about their protégés' advancement potential predict the career support they provide and the quality of their relationship, and that these effects vary by gender. Using matched-pair designs, we tested our model in two field studies of mentors and their protégés (total n = 355 dyads). Supporting theoretical predictions, mentors showed less interest in their protégés' careers, provided less career guidance, experienced less respect, and were less satisfied with their relationship when they believed their protégé had low advancement potential. Protégés also experienced less respect in their relationship when their mentor perceived them as lacking potential. Gender played a nuanced role. While mentors saw female and male protégés as having equivalent advancement potential, female protégés were seen as having less potential and experienced less respect when assigned a male rather than a female mentor. Compared to their female counterparts, male mentors felt more respected in their relationship when they believed their assigned protégé had high potential. Our findings challenge assumptions about the career support and respect provided in mentoring programs, offer insights about the nuanced effects of gender, and call for interventions that help organizations fulfill the promise of mentoring.

Superior capsular reconstruction using the long head of the biceps does not negatively affect outcomes in terms of pain or stiffness in the repair of large rotator cuff tears at 6 months post-operatively: matched-pair design for equivalence study

Superior capsular reconstruction using the long head of the biceps does not negatively affect outcomes in terms of pain or stiffness in the repair of large rotator cuff tears at 6 months post-operatively: matched-pair design for equivalence study

The Effect of Photobiomodulation on Bone Mineral Density, Serum Vitamin D, and Bone Formation Markers in Individuals with Complete Spinal Cord Injuries with Osteoporosis.

Study design: A quasi-experimental study utilized a matched-pair design, administering photobiomodulation at four-sites on one side of the body and assigning control to the other side at corresponding sites. Objectives: This study aimed to assess photobiomodulation treatment effects on bone mineral density (BMD) measurement using dual-energy X-ray-absorptiometry in individuals with complete spinal cord injury (C.SCI) and osteoporosis. Methods: Eight patients received treatment at four-sites: forearm-mid-distal (MID), proximal-femur, distal-femur, and proximal-tibia, totaling 32 sites. Using an 830 nm gallium-aluminum-arsenide semiconductor laser irradiation was administered three times weekly for 8 weeks. Different doses (energy density) were determined depending on bone depth from skin surface, as assessed by sonography and adjusted through irradiation time to be 8, 10, and 12 J/cm2 for depths <1 cm, between 1 and 1.5 cm, and >1.5 cm, respectively, using 200 mW power to deliver the optimal isodose of laser at each depth of bone within each therapeutic site. BMD was measured at baseline, week 8 of treatment, and week 15 of follow-up. Serum 25-(OH)-vitamin D and bone formation markers including osteocalcin and bone-alkaline-phosphatase (B-ALP) were also assessed at baseline and week 8 of treatment. Results: Significant increases in BMD were noted in proximal-femur and forearm-MID at both week 8 and week 15. Serum 25-(OH)-vitamin D levels significantly increased after treatment. However, no notable changes were observed in distal-femur and proximal-tibia BMD or in osteocalcin and B-ALP levels. Conclusions: Photobiomodulation (830 nm) laser demonstrated efficacy in improving BMD at proximal-femur and forearm-MID in individuals with C.SCI. Moreover, the observed positive influence on vitamin D levels suggests a potential photobiomodulation role, warranting further investigation.

A comparison of walking performance between individuals with and without asymptomatic peripheral artery disease using the six-minute walk test and the incremental shuttle walk test.

Two walking tests including the six-minute walk test (6MWT) and the incremental shuttle walk test (ISWT) are widely used to evaluate functional ability in individuals with disease conditions. However, it remains unclear whether these walking tests effectively manifest clinical impairment in individuals with asymptomatic peripheral artery disease (PAD). We aimed (i) to compare the walking performance of individuals with and without asymptomatic PAD using the 6MWT and ISWT, and (ii) to investigate the correlation between ankle-brachial index and toe-brachial index (ABI-TBI) and the walking distance. A cross-sectional, crossover, matched pairs design was employed in this study. Asymptomatic PAD was diagnosed using ABI-TBI measurements. Seventy-six participants (38 with asymptomatic PAD and 38 without PAD) were randomly ordered to perform the walking tests. During the 6MWT, participants walked along the 30-meter corridor at their self-selected pace for six minutes, and the six-minute walk distance (6MWD) covered was recorded. In the ISWT, participants walked at a 12 prescribed speed level, and the incremental shuttle walk distance (ISWD) covered was recorded. Result revealed no difference in 6MWD between individuals with asymptomatic PAD and without PAD (mean distance: 501.6 m vs 516.8 m, p = 0.24). Asymptomatic PAD individuals exhibited a significantly shorter ISWD than those without PAD (median distance: 270 m vs 340 m, p = 0.003). No participants reported any leg pain symptoms during the 6MWT and ISWT. A statistically significant positive correlation was observed between the right leg TBI and ISWD in all participants (r = 0.23, p = 0.04). Individuals with asymptomatic PAD demonstrated poorer walking performance than those without PAD when assessed using ISWT but not the 6MWT. Asymptomatic PAD is also associated with diminished walking performance during the ISWT. Thus, ISWT may show the clinical impairment in this population.

MOVER tests for non-inferiority of the difference between two binary-outcome treatments in the matched-pairs design

ABSTRACT A non-inferiority trial is usually conducted to investigate whether a new drug/treatment is no worse than a reference drug/treatment by a small, pre-specified, non-inferiority margin. This study aimed to assess the non-inferiority of the difference between two binary-outcome treatments in a matched-pairs design based on the method of variance of estimates recovery (MOVER). The processes for estimating the confidence interval of a single proportion included in the MOVER are the Wilson score interval, Agresti – Coull interval, Jeffreys interval, modified Jeffreys interval, score method with continuity correction, and arcsin interval. The performance of the six MOVER tests, the fiducial test, and the restricted maximum likelihood estimation test were evaluated by comparing their type I error rates and power at different pre-assigned levels and with varying combinations of parameters. The evaluation results showed that the modified Jeffreys MOVER test can be a competitive alternative to the other recommended tests. It can control type I errors well, and its power is not inferior to other methods. The proposed tests were illustrated with three real-world examples.

Differences in social support, emotion invalidation, psychological needs, cognitive emotion regulation in maritally adjusted and maladjusted women in Pakistan: A matched pairs design.

The present study aimed to find out differences of social support, perceived emotion invalidation, psychological needs, and use of adaptive and maladaptive cognitive emotion regulation strategies in maritally adjusted and maladjusted after controlling for age, education, employment status, and depressive symptomatology. The cross-sectional study uses a matched pairs design. The sample was divided into two groups; maritally adjusted and maladjusted women (n = 40 pairs) on basis of scores obtained on revised-dyadic adjustment scale. Forty maritally adjusted women were matched with 40 maritally maladjusted women according to age, education, and employment status. Social support questionnaire, perceived invalidation of emotion scale, basic psychological need satisfaction frustration scale, cognitive emotion regulation questionnaire, and center for epidemiologic studies depression scale were administered. One-way ANCOVA revealed that maritally maladjusted women had lower level of social support [mean difference; -5.65(-9.97, -1.33), p < 0.05, partial η2 = 0.08] and more emotional invalidation [mean difference; 15.36(13.08, 17.65), p < 0.001, partial η2 = 0.71] compared to maritally adjusted women after controlling for the effect of depressive symptomatology. Maritally maladjusted women had more need frustration [mean difference; 10.75(7.59, 13.92), p < 0.001, partial η2 = 0.38] compared to maritally adjusted women. However, maritally adjusted women had more need satisfaction [mean difference; 13.36(9.67, 17.05), p < 0.001, partial η2 = 0.41] compared to maritally maladjusted women. Maritally adjusted women used more adaptive CER strategies (acceptance, refocus on planning and putting into perspective) [mean difference; 4.66(2.36, 6.95), p < 0.001, partial η2 = 0.18] compared to maritally maladjusted women whereas, maritally maladjusted women used more maladaptive strategies (self-blame, catastrophizing and blaming others) [mean difference; 4.66(2.77, 6.54), p < 0.001, partial η2 = 0.25] compared to maritally adjusted women. Maladjusted women had less social support and more emotional invalidation of emotions and psychological needs frustration. They used more maladaptive strategies to manage their negative emotions in comparison to maritally adjusted women. Identification of these cognitive emotion regulation strategies will help clinicians and counselors to devise psychological intervention targeting the use of adaptive strategies to minimize the negative mental health consequences.

Equivalence Assessment via the Difference Between Two AUCs in a Matched-Pair Design with Nonignorable Missing Endpoints

Equivalence Assessment via the Difference Between Two AUCs in a Matched-Pair Design with Nonignorable Missing Endpoints

The Impact of Family Firms and Supervisory Boards on Corporate Environmental Quality

This paper examines the impact of family ownership and supervisory board characteristics on carbon emission disclosure. It uses balanced panel data and a matched-pair design of 124 non-financial firms listed on the Indonesia Stock Exchange from 2017 to 2019. This study finds that family firms and larger boards improve, while female board members harm carbon emission performance. Further analyses reveal non-linear relationships between family ownership and carbon performance. When control rights are limited, family firms prioritize controlling managers and improving carbon quality. Conversely, they prioritize personal objectives over environmental concerns when there are high control rights, resulting in decreased carbon emission performance. Additionally, family board members generate more carbon information, indicating the family owners effectively utilize their position on the supervisory boards to influence the company’s carbon emission performance. Finally, the study reports that more faculty member boards seem to hurt carbon emission reduction efforts. This result suggests that the diversity of their professional experiences does not affect the environmental effectiveness of supervisory boards. Our findings highlight the importance of understanding SEW principles and their connection to families in comprehending Indonesian corporate carbon emissions disclosures. The findings of this study enrich the worldwide literature by exploring the potential benefits of family business environmental performance. This study also adds to the literature on corporate governance, especially the role played by supervisory boards. Our findings align with the resource dependence theory, emphasizing the central function of supervisory boards as a monitoring tool. This study is constrained by its reliance on carbon emission data extracted from the annual reports of public firms, with a particular emphasis on pre-COVID-19 data. Future research should focus on sustainability reports and explore the time frame encompassing COVID-19 (2020–2022 datasets) to determine any differences in the findings.

Pigeonhole Design: Balancing Sequential Experiments from an Online Matching Perspective

Practitioners and academics have long appreciated the benefits of covariate balancing when they conduct randomized experiments. For web-facing firms running online A/B tests, however, it still remains challenging in balancing covariate information when experimental subjects arrive sequentially. In this paper, we study an online experimental design problem, which we refer to as the online blocking problem. In this problem, experimental subjects with heterogeneous covariate information arrive sequentially and must be immediately assigned into either the control or the treated group. The objective is to minimize the total discrepancy, which is defined as the minimum weight perfect matching between the two groups. To solve this problem, we propose a randomized design of experiment, which we refer to as the pigeonhole design. The pigeonhole design first partitions the covariate space into smaller spaces, which we refer to as pigeonholes, and then, when the experimental subjects arrive at each pigeonhole, balances the number of control and treated subjects for each pigeonhole. We analyze the theoretical performance of the pigeonhole design and show its effectiveness by comparing against two well-known benchmark designs: the matched-pair design and the completely randomized design. We identify scenarios when the pigeonhole design demonstrates more benefits over the benchmark design. To conclude, we conduct extensive simulations using Yahoo! data to show a 10.2% reduction in variance if we use the pigeonhole design to estimate the average treatment effect. This paper was accepted by George Shanthikumar, data science. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.02184 .

Evaluation of Orexin-A Salivary Levels and its Correlation with Attention After Non-invasive Brain Stimulation in Female Volleyball Players

BackgroundThe capacity to change attention from one area to another depending on the many environmental circumstances present is a crucial aspect of selective attention and is strictly correlated to reaction time. The cholinergic system of the basal forebrain is crucial for attentive abilities. Several inputs, particularly orexin neurons, whose cell bodies are found in the postero-lateral hypothalamus, can activate the cholinergic system. The aim of this study was to investigate if high frequencies rTMS at dorsolateral prefrontal cortex (DLPFC) in highly trained volleyball players can change Orexin-A levels, attention and reaction time. This study was a double-blinded (participant and evaluator) matched-pair experimental design. Twenty right-handed female volleyball players were recruited for the study (age 24.6 ± 2.7 years; height 177.0 ± 5.5 cm; body mass 67.5 ± 6.5 kg; BMI 21.5 ± 1.2).ResultsThe main finding of this study was that 10 Hz rTMS to the DLPFC seems to increase Orexin-A salivary levels and the percentage of correct answers, while decreasing RT. After rTMS, the athletes show an increase in the percentage of correct answers immediately after the end of stimulation, and also after 15 and 30 min. Moreover, the athletes show decreases in reaction time after the end of stimulation and after 15 and 30 min to the end of stimulation, while no differences were found at the end of stimulation. Finally, the athletes show significant increases in Orexin-A salivary levels after stimulation with a peak after 30’ of the end.ConclusionThe results of our study seem to indicate that there is a relationship between salivary Orexin-A levels and RT. These results could provide useful tools for modulating sports training; in fact, if confirmed, they could lead coaches to offer their athletes rTMS sessions appropriately integrated with training. In fact, alternating attention is a mental flexibility that enables people to change their point of focus and switch between tasks requiring various levels of cognition.

Bootstrap Inference for Quantile Treatment Effects in Randomized Experiments with Matched Pairs

Abstract This paper examines methods of inference concerning quantile treatment effects (QTEs) in randomized experiments with matched-pairs designs (MPDs). Standard multiplier bootstrap inference fails to capture the negative dependence of observations within each pair and is therefore conservative. Analytical inference involves estimating multiple functional quantities that require several tuning parameters. Instead, this paper proposes two bootstrap methods that can consistently approximate the limit distribution of the original QTE estimator and lessen the burden of tuning parameter choice. Most especially, the inverse propensity score weighted multiplier bootstrap can be implemented without knowledge of pair identities.

Geographic pair matching in large-scale cluster randomized trials

Cluster randomized trials are often used to study large-scale public health interventions. In large trials, even small improvements in statistical efficiency can have profound impacts on the required sample size and cost. Location integrates many socio-demographic and environmental characteristics into a single, readily available feature. Here we show that pair matching by geographic location leads to substantial gains in statistical efficiency for 14 child health outcomes that span growth, development, and infectious disease through a re-analysis of two large-scale trials of nutritional and environmental interventions in Bangladesh and Kenya. Relative efficiencies from pair matching are ≥1.1 for all outcomes and regularly exceed 2.0, meaning an unmatched trial would need to enroll at least twice as many clusters to achieve the same level of precision as the geographically pair matched design. We also show that geographically pair matched designs enable estimation of fine-scale, spatially varying effect heterogeneity under minimal assumptions. Our results demonstrate broad, substantial benefits of geographic pair matching in large-scale, cluster randomized trials.

Comparison of the efficacy of Cf-252 neutron intracavitary brachytherapy monotherapy with neutron intracavitary brachytherapy plus external beam radiotherapy in stage IB1 cervical cancer

Comparison of the efficacy of Cf-252 neutron intracavitary brachytherapy monotherapy with neutron intracavitary brachytherapy plus external beam radiotherapy in stage IB1 cervical cancer

Evidence from Finland and Sweden on the relationship between early-life diseases and lifetime childlessness in men and women.

The percentage of people without children over their lifetime is approximately 25% in men and 20% in women. Individual diseases have been linked to childlessness, mostly in women, yet we lack a comprehensive picture of the effect of early-life diseases on lifetime childlessness. We examined all individuals born in 1956-1968 (men) and 1956-1973 (women) in Finland (n = 1,035,928) and Sweden (n = 1,509,092) to the completion of their reproductive lifespan in 2018. Leveraging nationwide registers, we associated sociodemographic and reproductive information with 414 diseases across 16 categories, using a population and matched-pair case-control design of siblings discordant for childlessness (71,524 full sisters and 77,622 full brothers). The strongest associations were mental-behavioural disorders (particularly among men), congenital anomalies and endocrine-nutritional-metabolic disorders (strongest among women). We identified new associations for inflammatory and autoimmune diseases. Associations were dependent on age at onset and mediated by singlehood and education. This evidence can be used to understand how disease contributes to involuntary childlessness.

Effects of Anodal Transcranial Direct Current Stimulation With Overground Gait Training on Lower Limb Performance in Individuals With Incomplete Spinal Cord Injury

Effects of Anodal Transcranial Direct Current Stimulation With Overground Gait Training on Lower Limb Performance in Individuals With Incomplete Spinal Cord Injury