138 research outputs found

    Tensile Properties, Collagen Content, and Crosslinks in Connective Tissues of the Immature Knee Joint

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    The major connective tissues of the knee joint act in concert during locomotion to provide joint stability, smooth articulation, shock absorption, and distribution of mechanical stresses. These functions are largely conferred by the intrinsic material properties of the tissues, which are in turn determined by biochemical composition. A thorough understanding of the structure-function relationships of the connective tissues of the knee joint is needed to provide design parameters for efforts in tissue engineering.The objective of this study was to perform a comprehensive characterization of the tensile properties, collagen content, and pyridinoline crosslink abundance of condylar cartilage, patellar cartilage, medial and lateral menisci, cranial and caudal cruciate ligaments (analogous to anterior and posterior cruciate ligaments in humans, respectively), medial and lateral collateral ligaments, and patellar ligament from immature bovine calves. Tensile stiffness and strength were greatest in the menisci and patellar ligament, and lowest in the hyaline cartilages and cruciate ligaments; these tensile results reflected trends in collagen content. Pyridinoline crosslinks were found in every tissue despite the relative immaturity of the joints, and significant differences were observed among tissues. Notably, for the cruciate ligaments and patellar ligament, crosslink density appeared more important in determining tensile stiffness than collagen content.To our knowledge, this study is the first to examine tensile properties, collagen content, and pyridinoline crosslink abundance in a direct head-to-head comparison among all of the major connective tissues of the knee. This is also the first study to report results for pyridinoline crosslink density that suggest its preferential role over collagen in determining tensile stiffness for certain tissues

    Impact of the COVID-19 Pandemic on Patient Preferences and Decision Making for Symptomatic Urolithiasis

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    Background: Pandemic restrictions have changed how patients approach symptomatic kidney stones. We used a mixed-methods digital ethnographic approach to evaluate social media discussions about patient concerns and preferences for urolithiasis care during the COVID-19 pandemic. Materials and Methods: We retrospectively analyzed kidney stone-related discussions on a large social media platform using qualitative analysis and natural language processing-based sentiment analysis. Posts were mined for demographic details, treatments pursued, and health care encounters. Pre-COVID-19 (January 1, 2020-February 29, 2020) and COVID-19 (March 1, 2020-June 1, 2020) posts were extracted from the popular online Reddit discussion board, r/KidneyStones, which is dedicated to discussions related to urolithiasis. Results: We extracted n = 649 posts (250 pre-COVID-19, 399 COVID-19); 150 from each cohort underwent thematic analysis and data extraction. Quantitative sentiment analysis was performed on 418 posts (179 pre-COVID-19, 239 COVID-19) that described stone-related decision making before intervention. Notable discussion themes during COVID-19 focused on barriers to care and concerns about stone management. Discussants exhibited more negative and anxious tones during COVID-19, based on sentiment analysis (p \u3c 0.01). Patient preferences shifted away from in-person visits and procedures (p \u3c 0.001). Mean reported stone size among those visiting emergency room (ER) increased from 5.1 to 10.5 mm (p \u3c 0.001). The proportion of discussants preferring conservative management with stones ≥10 mm increased (12.5% pre-COVID-19 vs 26% during COVID-19, p = 0.002). Opioid mentions increased from 9% to 27% of posts (p \u3c 0.001) and were most associated with conservative management discussions. Conclusions: Online discussion forums provide contemporaneous insight into patients\u27 experiences during a time when traditional patient-centered research methodologies are limited due to social distancing. During the pandemic, patients with symptomatic kidney stones expressed anxiety regarding outpatient encounters and reluctance toward procedural intervention. Patients opted instead for at-home conservative treatment beyond clinical guidelines and reserved ER visits for larger stones, potentially causing self-harm. Opioid discussions proliferated, an alarming consequence of the pandemic

    International equity portfolio investment and enforcement of insider trading laws: a cross-country analysis

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    In this study, we examine the effects of stringent insider trading laws’ enforcement, institutions and stock market development on international equity portfolio allocation using data from 44 countries over the period 2001-2015. Our results suggest that stringent insider trading laws and their enforcement exert a positive and significant impact on international portfolio investment allocation. Further analysis indicates that the interaction between a country’s institutional quality, stock market development and enforcement of insider trading laws have a positive and significant effect on international equity portfolio allocation. The findings of this study have implications for the design of portfolio investment trading strategies and contribute to the literature on foreign equity investment decisions

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