Lower Extremity Muscle Strength and Risk of Self-Reported Hip or Knee Osteoarthritis

Purpose: The purpose of this study was to investigate the gender-specific longitudinal association between quadriceps strength and self-reported, physician-diagnosed hip or knee osteoarthritis (OA). Methods: Subjects were 3081 community-dwelling adults who were free of OA, joint symptoms and injuries, completed a maximum treadmill exercise test, had isokinetic knee extension and flexion and isotonic leg press strength measurements taken at baseline and returned at least one written follow-up survey. Multivariate logistic regression was used to estimate odds ratios and 95% confidence intervals. Results: Women with moderate or high isokinetic quadriceps strength had a significantly reduced risk (55% to 64%) of hip or knee OA. A similar, nonsignificant trend was noted among men. Moderate isotonic leg press strength was protective for hip or knee osteoarthritis among men only. Conclusions: These results suggest that quadriceps weakness is an independent and modifiable risk factor for lower extremity OA, particularly among women

Air toxics provisions of the Clean Air Act: Potential impacts on energy

This report provides an overview of the provisions of the Clean Air Act and its Amendments of 1990 that identify hazardous air pollutant (HAP) emissions and addresses their regulation by the US Environmental Protection Agency (EPA). It defines the major energy sector sources of these HAPs that would be affected by the regulations. Attention is focused on regulations that would cover coke oven emissions; chromium emission from industrial cooling towers and the electroplating process; HAP emissions from tank vessels, asbestos-related activities, organic solvent use, and ethylene oxide sterilization; and emissions of air toxics from municipal waste combustors. The possible implications of Title III regulations for the coal, natural gas, petroleum, uranium, and electric utility industries are examined. The report discusses five major databases of HAP emissions: (1) TRI (EPA's Toxic Release Inventory); (2) PISCES (Power Plant Integrated Systems: Chemical Emissions Studies developed by the Electric Power Research Institute); (3) 1985 Emissions Inventory on volatile organic compounds (used for the National Acid Precipitation Assessment Program); (4) Particulate Matter Species Manual (EPA); and (5) Toxics Emission Inventory (National Aeronautics and Space Administration). It also offers information on emission control technologies for municipal waste combustors

Operation of a pilot alpha waste incinerator at the Savannah River Laboratory

The pilot incinerator was built and operated successfully at design throughput with simulated wastes. Operating ranges of stable incinerator performance were defined as a function of air and waste feed rates for different materials and mixtures of materials. The complete range of waste materials can be burned without producing tar or soot. The limiting capacity of this incinerator is 0.5 kg/h if all latex rubber is charged or approximately 0.84 kg/h with a waste mixture. Off-gas particulate sampling prior to scrubbing indicates negligible solid carryover. The only material which may present off-gas cleaning problems is a light white smoke which accompanies the burning of PVC. The incinerator was operated continuously between 850 and 1000/sup 0/C from startup on September 6, 1977 until shutdown on February 2, 1978. The 3.6-kW electric heater for the primary combustion chamber burned out on January 13; however, adequate burning temperatures were provided by the eight 1.25-kW heaters in the afterburner to maintain sootless burning. As a result, future incinerator operation will be at 900/sup 0/C rather than 1000/sup 0/C. After 5 months of operation, the condition of the ceramics was very good, and the metal components showed no deterioration or serious corrosion. The incinerator was modified by installing a different design gas burner block, and two baffles and a choke in the afterburner to increase turbulence and mixing. It was started up again on February 27, 1978. (DLC

Public perceptions of synthetic cooling agents in electronic cigarettes on Twitter

Amid a potential menthol ban, electronic cigarette (e-cigarette) companies are incorporating synthetic cooling agents like WS-3 and WS-23 to replicate menthol/mint sensations. This study examines public views on synthetic cooling agents in e-cigarettes via Twitter data. From May 2021 to March 2023, we used Twitter Streaming Application Programming Interface (API), to collect tweets related to synthetic cooling agents with keywords such as 'WS-23, ''ice, ' and'frozen.' The deep learning RoBERTa (Robustly Optimized BERT-Pretraining Approach) model that can be optimized for contextual language understanding was used to classify attitudes expressed in tweets about synthetic cooling agents and identify e-cigarette users. The BERTopic (a topic modeling technique that leverages Bidirectional Encoder Representations from Transformers) deep-learning model, specializing in extracting and clustering topics from large texts, identified major topics of positive and negative tweets. Two proportion Z-tests were used to compare the proportions of positive and negative attitudes between e-cigarette users (vapers) and non-e-cigarette-users (non-vapers). Of 6, 940, 065 e-cigarettes-related tweets, 5, 788 were non-commercial tweets related to synthetic cooling agents. The longitudinal trend analysis showed a clear upward trend in discussions. Vapers posted most of the tweets (73.05%, 4, 228/5, 788). Nearly half (47.87%, 2, 771/5, 788) held a positive attitude toward synthetic cooling agents, which is significantly higher than those with a negative attitude (19.92%, 1, 153/5, 788) with a P-value < 0.0001. The likelihood of vapers expressing positive attitudes (60.17%, 2, 544/4, 228) was significantly higher (P < 0.0001) than that of non-vapers (14.55%, 227/1, 560). Conversely, negative attitudes from non-vapers (30%, 468/1, 560) were significantly (P < 0.0001) higher than vapers (16.2%, 685/4, 228). Prevalent topics from positive tweets included “enjoyment of specific vape flavors, ” “preference for lush ice vapes, ” and “liking of minty/icy feelings.” Major topics from negative tweets included “disliking certain vape flavors” and “dislike of others vaping around them.” On Twitter, vapers are more likely to have a positive attitude toward synthetic cooling agents than non-vapers. Our study provides important insights into how the public perceives synthetic cooling agents in e-cigarettes. These insights are crucial for shaping future U.S. Food and Drug Administration (FDA) regulations aimed at safeguarding public health

Osteogenic lineage restriction by osteoprogenitors cultured on nanometric grooved surfaces – the role of focal adhesion maturation

The differentiation of progenitor cells is dependent on more than biochemical signalling. Topographical cues in natural bone extracellular matrix guide cellular differentiation through the formation of focal adhesions, contact guidance, cytoskeletal rearrangement and ultimately gene expression. Osteoarthritis and a number of bone disorders present as growing challenges for our society. Hence, there is a need for next generation implantable devices to substitute for, or guide, bone repair in vivo. Cellular responses to nanometric topographical cues need to be better understood in vitro in order to ensure the effective and efficient integration and performance of these orthopaedic devices. In this study, the FDA approved plastic polycaprolactone, was embossed with nanometric grooves and the response of primary and immortalised osteoprogenitor cells observed. Nanometric groove dimensions were 240 nm or 540 nm deep and 12.5 μm wide. Cells cultured on test surfaces followed contact guidance along the length of groove edges, elongated along their major axis and showed nuclear distortion, they formed more focal complexes and a lower proportions of mature adhesions relative to planar controls. Down-regulation of the osteoblast marker genes RUNX2 and BMPR2 in primary and immortalised cells was observed on grooved substrates. Down-regulation appeared to directly correlate with focal adhesion maturation, indicating the involvement of ERK 1/2 negative feedback pathways following integrin mediated FAK activation

Knee joint coordination during single-leg landing in different directions

Knee joint coordination during jump landing in different directions is an important consideration for injury prevention. The aim of the current study was to investigate knee and hip kinematics on the non-dominant and dominant limbs during landing. A total of 19 female volleyball athletes performed single-leg jump-landing tests in four directions; forward (0°), diagonal (30° and 60°) and lateral (90°) directions. Kinematic and ground reaction force data were collected using a 10-camera Vicon system and an AMTI force plate. Knee and hip joint angles, and knee angular velocities were calculated using a lower extremity model in Visual3D. A two factor repeated measures ANOVA was performed to explore limb dominance and jump direction. Significant differences were seen between the jump directions for; angular velocity at initial contact (p < 0.001), angular velocity at peak vertical ground reaction force (p < 0.001), and knee flexion excursion (p = 0.016). Knee coordination was observed to be poorer in the early phase of velocity-angle plot during landing in lateral direction compared to forward and diagonal directions. The non-dominant limb seemed to have better coordination than the dominant limb during multi-direction jump landing. Therefore, dominant limbs appear to be at a higher injury risk than non-dominant limbs

The effect of proprioceptive knee bracing on knee stability during three different sport related movement tasks in healthy subjects and the implications to the management of Anterior Cruciate Ligament (ACL) injuries

Abstract Introduction: Proprioceptive knee braces have been shown to improve knee mechanics, however much of the work to date has focused on tasks such as slow step down tasks rather than more dynamic sporting tasks. Objective: This study aimed to explore if such improvements in stability may be seen during faster sports specific tasks as well as slower tasks. Method: Twelve subjects performed a slow step down, single leg drop jump and pivot turn jump with and without a silicone web brace. 3D kinematics of the knee were collected using a ten camera Qualisys motion analysis system. Reflective markers were placed on the foot, shank, thigh and pelvis using the Calibrated Anatomical Systems Technique. A two way ANOVA with repeated measures was performed with post-hoc pairwise comparison to explore the differences between the two conditions and three tasks. Results: Significant differences were seen in the knee joint angles and angular velocities in the sagittal, coronal and transverse planes between the tasks. The brace showed a reduction in knee valgum and internal rotation across all tasks, with the most notable effect during the single leg drop jump and pivot turn jump. The transverse plane also showed a significant reduction in the external rotation knee angular velocity when wearing the brace. Discussion: The brace influenced the knee joint kinematics in coronal and transverse planes which confirms that such braces can have a significant effect on knee control during dynamic tasks. Further studies are required exploring the efficacy of proprioceptive braces in athletic patient cohort. Acknowledgements This study is partly founded by Erasmus+ program who have sponsored two masters students. The braces were supplied by DJO Global, Inc. The suppliers played no role in the design, execution, analysis and interpretation of the data or writing of this study

Cigarette smoking and risk of total knee replacement for severe osteoarthritis among Chinese in Singapore - the Singapore Chinese health study

10.1016/j.joca.2014.03.013Osteoarthritis and Cartilage226764-77