Research and application of bag filter system for railway ballast bed coal suction vehicles: An optimization and application study.

The current bag filter system used by railway ballast bed coal suction vehicles for cleaning coal dust from railway tunnels has low operational efficiency and generates significant volumes of dust. This paper describes a simulation test unit designed to enhance the dust removal performance in railway tunnels. The flow field inside the simulation test unit is investigated under different operating conditions through numerical simulations, and the variations in air volume and working resistance, total dust collection efficiency, and optimal operating parameters of a pulse cleaning system are identified through a series of experiments. The numerical results show that the pulse cleaning system does not significantly affect the uniformity of the flow field distribution at the bottom of the filter cartridge during the process of operation. The experimental research indicates that the simulation test unit satisfies the design requirements, achieving an average total dust removal efficiency of 99.93%. A field application shows that the total dust mass concentration at the operator position can be reduced from 335.8 mg∙m-3 to 4.2 mg∙m-3, effectively improving the operating environment within the tunnel.

Exosomes Derived from Quercetin-Treated Bone Marrow Derived Mesenchymal Stem Cells Inhibit the Progression of Osteoarthritis Through Delivering miR-124-3p to Chondrocytes.

Osteoarthritis (OA) is a chronic disease characterized by the progressive loss of cartilage and failure of the diarrheal joint. Quercetin has been reported to attenuate the development of OA. Bone marrow derived mesenchymal stem cell (BMSC)-derived exosomes are involved in OA progression. However, the role of BMSC-derived exosomes in quercetin-mediated progression of OA remains unclear. Western blotting and RT-qPCR were used to assess protein and mRNA levels, respectively. CCK8 assay was performed to assess cell viability, and cell apoptosis was assessed using flow cytometry. A dual-luciferase assay was performed to assess the relationship between miR-124-3p and TRAF6 expression. Furthermore, in vivo experiments were performed to test the function of exosomes derived from Quercetin-treated BMSCs in OA patients. IL-1ß significantly inhibited the viability of chondrocytes, whereas the conditioned medium of Quercetin-treated BMSCs (BMSCsQUE-CM) reversed this phenomenon through exosomes. IL-1ß notably upregulated MMP13 and ADAMT5 and reduced the expression of COL2A1 in chondrocytes, which were rescued by BMSCsQUE-CM. The effects of BMSCsQUE-CM on these three proteins were reversed in the absence of exosomes. Exosomes can be transferred from BMSCs to chondrocytes, and exosomes derived from Quercetin-treated BMSCs (BMSCsQue-Exo) can reverse the apoptotic effects of IL-1ß on chondrocytes. The level of miR-124-3p in BMSCs was significantly upregulated by quercetin, and miR-124-3p was enriched in BMSCsQue-Exo. TRAF6 was identified as a direct target of miR-124-3p, and BMSCsQue-Exo abolished the IL-1ß-induced activation of MAPK/p38 and NF-κB signaling. Furthermore, BMSCsQue-Exo significantly attenuated OA progression in vivo. Exosomes derived from Quercetin-treated BMSCs inhibited OA progression through the upregulation of miR-124-3p.

[A retrospective study on manual reduction combined with Chinese Orthopaedic ankle external fixator in the treatment of trimalleolar fracture].

OBJECTIVE: To evaluate the needle puncture safety and clinical efficacy of manual reduction combined with external fixation of ankle frame in the treatment of trimalleolar fracture under the guidance of Chinese Osteosynthesis (CO) theory. METHODS: The clinical data of 118 patients with trimalleolar fractures admitted from December 2010 to December 2021 were retrospectively analyzed. Fifty-three patients were treated with manual reduction combined with external fixation of ankle frame(observation group). Sixty-five patients were treated with open reduction and internal fixation with plate and screws(control group). The operation time, hospitalization days, non-weight-bearing time of the affected limb, clinical healing time of fracture, incidence of complications, visual analogue scale (VAS) before and 1 month after operation, and American Orthopedic Foot and Ankle Society(AOFAS) score of ankle joint before and 1 year after operation were compared between the two groups. RESULTS: Patients in both groups were followed up for more than 1 year. All patients were followed up, and the duration ranged from 14 to 70 months, with an average of(35.28±14.66) months. There were statistically significant in operation time, hospitalization days, non-load-bearing time of affected limbs, clinical healing time of fractures and VAS score one month after operation between the two groups. One month after operation, the VAS score of the observation group was lower than that of the control group(t=3.343, P=0.001). The operation time of the observation group was significantly shorter than that of the control group(t=9.091, P=0.000). The hospitalization days in the observation group were significantly less than those in the control group(t=5.034, P=0.000). The non-load-bearing time of the affected limb in the observation group was significantly shorter than that in the control group(t=11.960, P=0.000). The clinical healing time of fracture in the observation group was significantly shorter than that in the control group(t=4.007, P=0.000). There was no significant difference in AOFAS score between the two groups one year after operation(t=0.417, P=0.678). In the observation group, there were 2 cases of pinhole infection and 3 cases of loss of reduction less than 2 mm. There were 3 cases of surgical incision infection in the control group. There was no significant difference in the incidence of complications between the two groups(χ2=0.446, P=0.504). CONCLUSION: Manual reduction combined with external fixation is safe and effective in the treatment of trimalleolar fracture under the guidance of CO theory, and the function of ankle joint recovers well after operation. This therapy has good clinical value.

Manual Reduction and Plaster External Fixation for the Treatment of Closed Total Talus Dislocation: Case Report and Literature Review.

BACKGROUND: Total dislocation of the talus from all its surrounding joints (talonavicular, tibiotalar, subtalar) is one kind of serious injury of the lower extremity with rare occurrence. It is usually accompanied by fractures of the talus and its periphery, as well as severe soft tissue injury, which is difficult to reset. Complications such as skin necrosis and infection are prone to occur in the early stage, and talus necrosis are prone to occur in the late stage, all of which aggravate disease severity and increase difficulties for its treatment. CASE PRESENTATION: Herein, we reported a case of right talus total dislocation accompanied by medial malleolus fracture and posterior tubercle fracture caused by traffic accident. One hour after injury, the doctor tried to perform manual reduction but failed. Then, we successfully performed manual reduction and plaster external fixation on this patient under anesthesia 6 h after injury, followed by the oral administration of Chinese medicine for 3 months. Twenty months of follow-up investigations revealed that no skin necrosis, talus dislocation, talus necrosis, or other complications occurred; no obvious joint degeneration was observed and the fractures of medial malleolus and talus healed well. MRI of ankle joint indicated the disappearance of ankle effusion caused by injury, and the bone marrow edema had also subsided at talus, medial malleolus, and lateral malleolus and calcaneus. Patient presented with no ligament relaxation, ankle instability, pain, swelling, or functional limitation of the injured limb. AOFAS score reached 100. Daily functions and recreation activities were recovered back to the normal level. CONCLUSION: For patients with closed total dislocation of the talus, fine therapeutic effects can be achieved by early closed manual reduction and plaster external fixation under anesthesia, in combination with oral Chinese herbal medicine afterwards. It is worthy of reference for clinicians.

An Efficient Multi-Dimensional Resource Allocation Mechanism for Beam-Hopping in LEO Satellite Network.

Low Earth Orbit (LEO) satellite communication networks have become an important means to provide internet access services for areas with limited infrastructure. Compared with the Geostationary Earth Orbit (GEO) satellites, the LEO satellites have limited on-board communication caching and calculating resources. Furthermore, the distribution of traffic requests is dynamically changing and uneven due to the relative movement between the LEO satellites and the ground. Therefore, how to schedule the multi-dimensional resources is an important issue for the LEO satellite communication networks. Beam-hopping is an efficient approach to improve the resource utilization by dynamically allocating time, power, and frequency according to the traffic requests. This paper proposes an efficient multi-dimensional resource allocation mechanism for beam-hopping in LEO satellite networks, which simultaneously satisfies the GEO interference avoidance. First, we construct the beam-hopping model of LEO satellites, and formulate the resource optimization problem. Second, we provide the weighted greedy strategy to determine the illumination pattern. In order to reduce the search space, the cells are clustered to non-interference clusters. Then, an improved genetic algorithm is provided to jointly allocate the communication resources. Finally, we construct various simulations to evaluate our proposed mechanism. Compared with the random-BH, polling-BH and traditional genetic algorithm, our algorithm achieves better performance in terms of both system throughput, access success rate, average delay and fairness between cells. The performance improvement is more significant in scenarios where traffic demand is unevenly distributed.

[Soft tissue changes observed through musculoskeletal ultrasound in the treatment of knee osteoarthritis with needle-knife].

OBJECTIVE: To study soft tissue changes observed through musculoskeletal ultrasound (MSUS) in the treatment of knee osteoarthritis with needle-knife, so as to provide MSUS basis for needle-knife in the treatment of knee osteoarthritis. METHODS: Forty patients with knee osteoarthritis treated in the Third Affiliated Hospital of Beijing University of Chinese Medicine from December 2011 to December 2012 were selected according to inclusion and exclusion criteria. All the patients were treated with needle-knife release method. The VAS scores and knee joint circumference were recorded before treatment and 2 weeks after treatment. The changes of knee joint hydrops articuli and joint synovial thickness were measured through MSUS. RESULTS: The knee pain index was 6.850 +/- 1.417 before treatment and 2.790 +/- 1.299 after treatment;the index after treatment was lower than that of before treatment. The knee joint circumference was 407.320 +/- 45.151 mm before treatment and 391.240 +/- 41.129 mm after treatment; the knee joint circumference decreased after treatment. The amount of hydrops articuli observed by musculoskeletal ultrasound showed that 47 knees were cured, 19 knees improved and 2 knees failed. The synovial membrane thickness: 43 knees cured, 17 knees improved and 8 knees failed. CONCLUSION: The hydrops articuli and synovial thickness of knee joint of patients with knee osteoarthritis observed under the MSUS is consistent with the main symptoms and signs, which suggests that MSUS observation on soft tissue changes before and after needle knife in the treatment of knee osteoarthritis with high reliability.

[Analysis of the failure mechanisms of the revision hip arthroplasties].

OBJECTIVE: To investigate the failure mechanisms of revision hip arthroplasties and evaluate the effects of surgical technique, prosthesis design and patient-related risk factors on different failure mechanisms. METHODS: A review of all revision hip arthroplasties from November 1995 to June 2008 identified 30 patients who underwent 30 revisions with 18 males and 12 females. The overall mean age for primary arthroplasties was 49 years (range 25-68 years) and 53 years (range 27-72 years) for index revision arthroplasties and the average interval between these two operations was 43.8 months (0-156 months). The failure mechanisms of index revision arthroplasties and primary arthroplasties were assessed and compared. Direct comparisons were made of data for the different age categories in terms of time to failures and reasons for failures. RESULTS: Regarding revision or prosthesis removal as the end point of the study, the reasons for 30 revision arthroplasties were aseptic loosening in 22 hips (73.3%), infection in 4 hips (13.3%), periprosthetic fracture in 3 hips and instability in 1 hip (3.3%). The overall mean age for last arthroplasties or prosthesis removal was 58 years (range 38-77 years) with an average interval of 78.8 months (range 1-216 months) from previous revision arthroplasties. The mean time to failure for patients above 60 years of age was significantly shorter than patients below 60 years of age (P < 0.01). CONCLUSION: The majority of failure mechanisms of revision hip arthroplasties are ineffective fixation of revisional implants and recurrence of local infection, which reveals the limitations to joint reconstruction philosophy and surgical technique.

[An investigation on failure mechanisms of primary 327 hip arthroplasties].

OBJECTIVE: To summarize the detailed failure mechanisms of revision hip arthroplasties and related risk factors. METHODS: From November 1988 to July 2008 revision of total hip arthroplasties was performed in 327 patients. The medical history, clinical and imaging material and operation records were investigated. RESULTS: Regarding revision as the end point of the study, the reasons for 327 revision arthroplasties were aseptic loosening in 226 hips (69.1%), infection in 52 hips (15.9%), periprosthetic fracture in 22 hips (6.7%), instability in 17 hips (5.2%), stem fracture in 5 hips (1.5%) and liner dissociation in 5 hips (1.5%). CONCLUSIONS: The main failure mechanisms of primary hip arthroplasties are aseptic loosening and infection of implants, which could be attributed to improper selection of operation indications and implants and limitations to surgical philosophy and technique.