To compare gait parameters during single-task and dual-task walking in older adults, and to examine differences in dual-task costs between individuals with high versus low balance abilities under different task conditions.

BACKGROUND:Scaffold materials serve as platforms that provide space and structure,playing a crucial role in the regeneration of cartilage tissue.Scholars from around the world are exploring different approaches to fabricate more ideal scaffold materials. OBJECTIVE:To review the design principles and preparation methods of cartilage scaffolds,and to further explore the advantages and limitations of various preparation methods. METHODS:Literature searches were conducted on the databases of CNKI,WanFang Data,PubMed,and FMRS from 1998 to 2023.The search terms were"cartilage repair,cartilage tissue engineering,cartilage scaffold materials,preparation"in Chinese and English.A total of 57 articles were ultimately reviewed. RESULTS AND CONCLUSION:(1)The articular cartilage has a unique structure and limited self-repair capacity after injury.Even if self-repair occurs,the newly formed cartilage is typically fibrocartilage,which is far inferior to normal articular cartilage in terms of structure and mechanical properties.It is difficult to maintain normal function and often leads to degenerative changes.Currently,the design and fabrication of scaffold materials for cartilage repair need to consider the following aspects:biocompatibility and biodegradability,suitable pore structure and porosity,appropriate mechanical properties,and bioactivity.(2)Research on the preparation of cartilage scaffolds has made significant progress,continuously introducing new preparation methods and optimization strategies.These methods have their advantages and disadvantages,providing more possibilities for customized preparation and functional design of cartilage scaffolds according to specific requirements.

BACKGROUND:Bone formation is the process by which osteoblasts synthesize and secrete osteoid and promote its mineralization,which generally involves mechanical signal transduction.Osteoblasts are primarily regulated by mechanical factors such as gravity,compressive stress,tensile stress,fluid shear stress,and hydrostatic pressure in vivo,and different mechanical stimuli modulate the proliferation,differentiation,and apoptosis of osteoblasts through various mechanisms,including hormones,cytoskeletal proteins,and microRNAs.By clarifying the effects of biomechanical forces on osteoblasts,it provides ideas and a reference basis for the treatment of osteometabolic diseases involving osteoblasts. OBJECTIVE:To review the effects of different biomechanical forces on the biological characteristics of osteoblasts. METHODS:We conducted a literature search using PubMed,Web of Science,FMRS,CNKI,and WanFang databases for relevant publications published from 2000 to 2023,covering basic research and tissue engineering studies related to the effects of biomechanical forces on osteoblasts.Ultimately,a total of 70 articles were reviewed. RESULTS AND CONCLUSION:Different biomechanical forces have an impact on the biological characteristics of osteoblasts,including proliferation,differentiation,and apoptosis,and these effects are dependent on the intensity and duration of the applied force.Specifically,the effects are as follows:(1)Under microgravity conditions,osteoblast proliferation and differentiation are inhibited,resulting in a decrease in bone density and the development of osteoporosis.(2)Compared to microgravity,hypergravity has a promoting effect on osteoblast proliferation.(3)The effects of compressive stress on osteoblasts are dependent on the loading intensity and time.Appropriate compressive stress can promote osteoblast proliferation and differentiation,which is beneficial for bone tissue formation and repair,while excessive compressive stress can cause osteoblast apoptosis and bone tissue destruction.(4)The biological effects of different types of tensile stress on osteoblasts differ.Studies have shown that a strain rate within the range of 0-12%has a promoting effect on osteoblast proliferation.(5)Fluid shear stress can promote osteoblast proliferation and differentiation and enhance the bone-inducing effect of biomaterials.(6)Static hydrostatic pressure can affect the biological behavior of osteoblasts,including proliferation,differentiation,and apoptosis,and these effects are closely related to the time and intensity of the pressure.Understanding the effects of different biomechanical forces on osteoblasts is of great significance for a deeper understanding of bone growth and maintenance mechanisms.

Objective:To explore the clinical efficacy of operative treatment of geriatric pelvic fractures.Methods:A retrospective study was conducted to analyze the clinical data of 55 geriatric patients with pelvic fracture who had been operatively treated at Department of Orthopaedic Trauma, Beijing Jishuitan Hospital from January 2020 to October 2023. There were 13 males and 42 females with an age of 72.0 (68.0, 83.3) years. By the AO/OTA classification, there were 47 cases of type B and 8 cases of type C; by the classification for fragility fractures of pelvis, there were 5 cases of type Ⅱ, 44 cases of type Ⅲ, and 6 cases of type Ⅳ. The patients received operative treatment 4.0 (3.0, 6.3) days after injury. Of the 10 patients treated by open reduction and closed reduction, the posterior ring was fixated by a plate in 7 and by screws in 3, and the anterior ring was fixated by either a plate, an external fixator or a minimally invasive anterior pelvic ring internal fixator except in the 2 cases receiving no fixation. Of the other 45 patients treated by closed reduction and fixation, the posterior ring was all fixated by screws except in the 2 cases receiving no fixation, and the anterior ring was fixated by either screws, an external fixator or a minimally invasive anterior pelvic ring internal fixator except in the 10 cases receiving no fixation. The major peri-operative complications, quality of fracture reduction, mortality, and functional recovery of the pelvis at the last follow-up were recorded.Results:There were no major peri-operative complications. According to the Matta criteria, the quality of fracture reduction was excellent in 31, good in 14, fair in 8 and poor in 2 cases, giving a good to excellent rate of 81.8% (45/55). Fifty-four cases were followed up for (15.4±9.1) months and 1 case was lost to the follow-up. Four cases died within 1 year after operation, giving a mortality of 7.4% (4/54). The modified Majeed score at the last follow-up was 69 (54, 76) for the 46 cases who had been followed up for longer than 4 months; the functional recovery of the pelvis at the last follow-up was rated as excellent in 27 cases, as good in 8 cases and as fair in 11 cases, giving a good to excellent rate of 76.1% (35/46) according to the criteria proposed by the faculty of the writers. The internal fixation failed in 3 cases during the follow-up.Conclusion:For the geriatric pelvic fractures, operative treatment can lead to satisfactory clinical outcomes.

Objective:To assess the rationality of the maximum lesion diameter of 15 mm in prostate imaging reporting and data system(PI-RADS)as a criterion for upgrading a lesion from category 4 to 5 and improve it to enhance the prediction of clinically significant prostate cancer(csPCa).Methods:In this study,the patients who underwent prostate magnetic resonance imaging(MRI)and prostate biopsy at Peking University First Hospital from 2019 to 2022 as a development cohort,and the patients in 2023 as a validation cohort were reviewed.The localization and maximum diameter of the lesion were fully evalua-ted.The area under the curve(AUC)and the cut-off value of the maximum diameter of the lesion to pre-dict the detection of csPCa were calculated from the receiver operating characteristics(ROC)curve.Confounding factors were reduced by propensity score matching(PSM).Diagnostic efficacy was com-pared in the validation cohort.Results:Of the 589 patients in the development cohort,358(60.8％)lesions were located in the peripheral zone and 231(39.2％)were located in the transition zone,and 496(84.2％)patients detected csPCa.The median diameter of the lesions in the peripheral zone was smaller than that in the transition zone(14 mm vs.19 mm,P＜0.001).In the ROC analysis of the maximal diameter on the csPCa prediction,there was no statistically significant difference between the peri-pheral zone(AUC=0.709)and the transition zone(AUC=0.673,P=0.585),and the cut-off values were calculated to be 11.5 mm for the peripheral zone and 16.5 mm for the migrating zone.By calcula-ting the Youden index for the cut-off values in the validation cohort,we found that the categorisation by lesion location led to better predictive results.Finally,the net reclassification index(NRI)was 0.170.Conclusion:15 mm as a criterion for upgrading the PI-RADS score from 4 to 5 is reasonable but too general.The cut-off value for peripheral zone lesions is smaller than that in transitional zone.In the future consideration could be given to setting separate cut-off values for lesions in different locations.

Objective:To explore the short-term efficacy of fixation with a 3D printed individualized custom-made plate in the treatment of elderly patients with periprosthetic femoral fracture.Methods:Retrospectively analyzed were the 5 elderly patients with periprosthetic femoral fracture who had been treated by fixation with a 3D printed individualized custom-made plate from January 2022 to July 2022 at Department of Orthopaedics and Traumatology, Beijing Jishuitan Hospital. There were 3 males and 2 females, aged 81, 86, 77, 91 and 87 years, respectively. One left and 4 right limbs were affected. Vancouver classification: type B1 ( n=3), type B2 ( n=1), and type C ( n=1). The time from operation to injury was 5, 6, 10, 5 and 7 days, respectively. Preoperatively, the femur affected, prosthesis and individualized plate with a greater trochanteric hook, loop cable channel and bone-like trabecular microporous structure were custom-made by 3D printing according to 1:1 models. Virtual operations were simulated to formulate surgical protocols. The operation time, length of surgical incision, intraoperative blood loss and transfusion, hospital stay, hip function and complications at the last follow-up were recorded. Results:The 5 patients were followed up for 12, 7, 10, 3 and 6 months, respectively. There were no events of superficial incision or deep prosthesis infection. Respectively, the operation time was 1.8, 1.7, 2.3, 2.0 and 3.3 h; the length of surgical incision 31, 30, 38, 27 and 30 cm; the intraoperative bleeding volume 400, 300, 300, 500 and 600 mL; the length of hospital stay 8, 9, 15, 14 and 11 d. Four patients received intraoperative blood transfusion of 300, 900, 150 and 1, 050 mL, respectively. One patient died of a heart attack 3 months after discharge; another patient developed dyskinesia at the contralateral limb 3 months after discharge due to cerebral infarction and died of recurrent cerebral infarction 7 months after discharge. At the last follow-up, the Harris hip scores of 3 patients were 86, 77 and 69 points, respectively. None of the patients had complications like breakage or loosening of implants.Conclusion:In the treatment of elderly patients with periprosthetic femoral fracture, fixation with a 3D printed individualized custom-made plate may lead to fine limb function and good short-term curative efficacy.

Objective:To investigate the early clinical effectiveness of using customized 3D printed acetabular augment to repair large acetabular bone defects in delayed total hip arthroplasty after failed treatment of acetabular fractures.Methods:A retrospective study was conducted to analyze the 6 patients who had undergone 3D printed acetabular augment to reconstruct acetabular bone defects in delayed total hip replacement from July 2021 to January 2023 after failed treatment of acetabular fractures. They were all males, with an age of (51.3±15.0) years. Paprosky classification: 2 cases of type ⅡB, 1 case of type ⅡC, and 3 cases of type ⅢA. Recorded were surgical time, intraoperative bleeding, hospitalization time, and visual analogue scale (VAS), and modified Merle d'Aubigné & Postel score, Harris hip score, and leg length discrepancy at the last follow-up.Results:For the 6 patients, the mean surgical time was (222.5±46.9) min, the mean intraoperative bleeding 1,100 (1,000, 2,625) mL, the mean hospitalization time (9.0±4.5) d, and the mean follow-up time (11.8±7.9) months. At the last follow-up, the VAS [(2.5±1.0) points] significantly decreased compared with the preoperative value [(6.2±0.8) points], the modified Merle d'Aubigné & Postel score [(13.2±2.1) points] and Harris hip score [(67.8±15.3) points] significantly increased compared with the preoperative values [(6.7±0.8) and (34.2±8.4) points], the vertical position of center of rotation [(22.5±5.2) mm] and the horizontal position of center of rotation [(40.7±2.6) mm] were significantly reduced compared with the preoperative values [(38.1±14.2) and (53.1±10.0) mm] ( P<0.05). At the last follow-up, the leg length discrepancy was (6.2±3.6) mm, showing no statistically significant difference from the preoperative value [(18.7±1.7) mm] ( P>0.05). At the last follow-up, no clear line at the cup-bone or augment-bone interface, or no possible prosthetic loosening or displacement was observed on the X-ray films. Conclusion:In delayed total hip arthroplasty after failed treatment of acetabular fractures, the customized 3D printed augment for repair of large bone defects in the acetabulum can reconstruct the normal rotation center of the hip joint, provide reliable stability for the cup prosthesis, and enable patients to obtain significant improvements in hip function.

Objective:To elucidate the recent therapeutic efficacy of the intelligent fracture reduction robotic system in managing pelvic fractures.Methods:A retrospective evaluation of 49 pelvic fracture patients treated using the intelligent fracture reduction robotic system at Beijing Jishuitan Hospital's trauma orthopedics department between March 2021 and December 2022 was conducted. The cohort included 30 males and 19 females, with a mean age of 51.51±18.71 years (20-92 years range). Fractures were classified according to the Tile system: B1 type in 2 cases, B2 in 7, B3 in 3, C1 in 30, and C2 in 3. The median interval between injury and surgery was 6 days, with a range of 2-22 days. The robotic system assisted in pelvic fracture reduction and stabilization surgeries. Preoperative and postoperative evaluations involved pelvic CT scans, anteroposterior, inlet, and outlet radiographic images. Fracture displacement and reduction outcomes were assessed via X-ray imagery. Data captured included intraoperative blood loss, duration of surgery, fracture stabilization techniques, and postoperative monitoring period. The Majeed scoring system gauged functional outcomes.Results:Of the patients, 48 underwent minimally invasive interventions with robotic assistance, while one case necessitated open reduction and internal fixation due to an unsuccessful reduction. The duration between injury and operation ranged from 2 to 22 days. Average surgical time stood at 206.5±7.1 minutes (105-440 min range), and median intraoperative blood loss was 100ml (10-600 ml range). Using the Matta reduction criteria, 30 postoperative cases exhibited excellent and 9 good outcomes for posterior pelvic ring displacement, translating to a 93% (38/41) positive rate. For anterior pelvic ring shifts, 45 showed excellent and 3 good outcomes, culminating in a 100% (48/48) success rate. Follow-up for the 48 cases lasted 11.0 months (3-23 months range), with the Majeed functional score averaging 81.9±17.0 points (42-100 point range). 27 cases scored excellent, and 11 good, yielding a combined positive outcome rate of 79.2% (38/48).Conclusion:Employing the intelligent fracture reduction robotic system in pelvic fracture treatments facilitates minimally invasive interventions and yields favorable short-term clinical results.

Objective:To explore the effect of job insecurity on work engagement, and examine the mediating role of job satisfaction and the moderating role of occupational proactive behavior.Methods:Using the convenient sampling method, nurses from Southern University of Science and Technology Hospital and Jiangyou Second People's Hospital were selected as the research objects in July 2022. General information questionnaire, Occupational Insecurity Scale, Occupational Satisfaction Scale, Work Engagement Scale and Occupational Proactive Behavior were used for questionnaire investigation. A total of 598 valid questionnaires were collected. Model 4 and Model 7 in the SPSS 22.0 Process were used to test the mediating effect and the moderated mediating effect respectively.Results:Occupational insecurity was negatively correlated with occupational satisfaction and work engagement ( r=-0.202, -0.165, P<0.01) , while occupational satisfaction was positively correlated with work engagement ( r=0.549, P<0.01) . Work satisfaction played a completely mediating role in the effect of job insecurity on work engagement (mediating effect value: -0.090 9, 95% confidence interval: -0.14 - -0.04) , accounting for 65.30% of the total effect. Occupational active behavior positively moderated the relationship between job insecurity and job satisfaction (β=0.07, P<0.01) . Conclusions:Nurses' work engagement is at a high level, but occupational insecurity will reduce nurses' job satisfaction and thus reduce their work engagement. Nurses with high occupational proactive behavior can alleviate the weakening of job insecurity on job satisfaction.

Objective:To describe a systematic approach on identification of poisonous mushroom by investigating two cases of Omphalotus guepiniformis poisoning in Jianyang district, Nanping, Fujian province. Methods:Two incidents of food poisoning on 10 migrant workers were investigated. The remaining suspected mushroom samples were collected and the same fresh mushroom specimens were also collected in the following field investigations from the same dead tree and fallen trunk. These mushroom specimens were identified based on morphological and phylogenetic analyses.Results:On November 24 and 26, 2018, 8 and 2 migrant workers from Jianyang District, Nanping ate wild mushrooms and developed acute nausea, vomiting, abdominal pain and other symptoms within 10 to 90 min after consumption. They were diagnosed as mushroom poisoning, with gastroenteritis as the main manifestation. Further analysis showed that the more poisonous mushroom were consumed, the shorter latency and longer duration of nausea and vomiting were resulted. After admission, gastric lavage, catharsis, acid preparation, gastric protection, fluid replenishment and other symptomatic support treatments were given in time, all patients were discharged in 1-3 d. Based on morphological and phylogenetic analyses, the samples were identified as O. guepiniformis. Conclusions:The two incidents were caused by accidental consumption of O. guepiniformis. Awareness education about poisonous mushroom should be provided to migrant workers to prevent more such poisoning incidents in the future.