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Osteoarthritis (OA) is the most common joint disease, and good therapeutic results are often difficult to obtain due to its complex pathogenesis and diverse causative factors. After decades of research and exploration of OA, it has been progressively found that subchondral bone is essential for its pathogenesis, and pathological changes in subchondral bone can be observed even before cartilage lesions develop. Osteoclasts, the main cells regulating bone resorption, play a crucial role in the pathogenesis of subchondral bone. Subchondral osteoclasts regulate the homeostasis of subchondral bone through the secretion of degradative enzymes, immunomodulation, and cell signaling pathways. In OA, osteoclasts are overactivated by autophagy, ncRNAs, and Rankl/Rank/OPG signaling pathways. Excessive bone resorption disrupts the balance of bone remodeling, leading to increased subchondral bone loss, decreased bone mineral density and consequent structural damage to articular cartilage and joint pain. With increased understanding of bone biology and targeted therapies, researchers have found that the activity and function of subchondral osteoclasts are affected by multiple pathways. In this review, we summarize the roles and mechanisms of subchondral osteoclasts in OA, enumerate the latest advances in subchondral osteoclast-targeted therapy for OA, and look forward to the future trends of subchondral osteoclast-targeted therapies in clinical applications to fill the gaps in the current knowledge of OA treatment and to develop new therapeutic strategies.

BackgroundIon cyclotron range of frequencies (ICRF) heating is one of the most widely used auxiliary heating methods in tokamaks. The HL-3 tokamak plans to equip a 6 MW ICRF heating system to conduct discharge experiments of high-performance plasma.PurposeThis study optimizes the parameters of ICRF using numerical simulations with the purpose of supporting the reactor-level plasma in HL-3 in future.MethodsOn the basis of NBI heating in the HL-3 device, ICRF heating was considered, and the TRANSP code was employed to explore the influence of ICRF frequency and power in HL-3 on the neutron emission rate, as well as the distribution of fast ions. The ICRF frequency range was between 25 MHz and 40 MHz, and the ICRF power range was between 1 MW and 6 MW. The neutron signals based on the concept of neutron camera diagnosis were also simulated.ResultsThe simulation results show that the ICRF frequency and power significantly influence the neutron emission rate. The neutron emission rate is directly proportional to the ICRF heating power at a fixed ICRF frequency whilst the increase in the neutron emission rate significantly depends on the ICRF frequency when the ICRF heating power is fixed. Among the investigated parameters, the ICRF with a frequency of 30 MHz yields the maximum increase in the neutron emission rate. The simulation results of fast ions demonstrate that the synergetic heating of neutral beam injection and ICRF can heat fast ions up to 1 MeV after considering ICRF heating, which effectively increases the neutron emission rate. The simulation results of neutron camera indicate that neutron camera can effectively measure the changes in neutron emission rate and distribution profile caused by ICRF heating.ConclusionsThe simulation results demonstrate that the appropriate selection of the ICRF frequency and power can effectively increase the neutron emission rate in HL-3 experiments, the optimal combination of ICRF frequency/power is 30 MHz/6 MW for the scenario analyzed in this study. The simulation of neutron camera for HL-3 provides a reference for designing future neutron camera systems and measuring neutron spatial distributions.

Osteoarthritis (OA) is a prevalent cause of joint algesia, loss of function, and disability in adults, with cartilage injury being its core pathological manifestation. Since cartilage damage is non-renewable, the treatment outcome in the middle and late stages of OA is unsatisfactory, which can be minimized by changing lifestyle and other treatment modalities if diagnosed and managed in the early stages, indicating the importance of early diagnosis and monitoring of cartilage injury. Ultrasound technology has been used for timely diagnosis and even cartilage injury treatment, which is convenient and safe for the patient owing to no radiation exposure. Studies have demonstrated the effectiveness of ultrasound and its various quantitative ultrasound parameters, like ultrasound roughness index (URI), reflection coefficient (R), apparent integrated backscatter (AIB), thickness, and ultrasound elastography, in the early and accurate assessment of OA cartilage pathological changes, including surface and internal tissue, hardness, and thickness. Although many challenges are faced in the clinical application of this technology in diagnosis, ultrasound and ultrasound-assisted techniques offer a lot of promise for detecting early cartilage damage in OA. In this review, we have discussed the evaluation of ultrasonic cartilage quantitative parameters for early pathological cartilage changes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhang, Ning, Lu, Zhou, Shao, Yang and Hao.)

In magnetic resonance examination, the interaction between implants and the radio frequency (RF) fields induces heating in human tissue and may cause tissue damage. To assess the RF-induced heating of implants, three steps should be executed, including electromagnetic model construction, electromagnetic model validation, and virtual human body simulations. The crucial step of assessing RF-induced heating involves the construction of a test environment for electromagnetic model validation. In this study, a hardware environment, comprised of a RF generation system, electromagnetic field measurement system, and a robotic arm positioning system, was established. Furthermore, an automated control software environment was developed using a Python-based software development platform to enable the creation of a high-precision automated integrated test environment. The results indicate that the electric field generated in this test environment aligns well with the simulated electric field, making it suitable for assessing the RF-induced heating effects of implants.