BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

BACKGROUND:Traumatic brain injury is a condition in which the normal function of the brain is disrupted by a bump or impact to the head.It is necessary to find effective treatments and objective targets that can help doctors diagnose the injury status and restore the brain function of patients. OBJECTIVE:To explore the effect of electroacupuncture combined with low-frequency transcranial ultrasound stimulation on the electroencephalographic signals of rats with traumatic brain injury. METHODS:Forty 6-week-old SPF male Sprague-Dawley rats were randomly divided into five groups:sham group,model group,electroacupuncture group,low-frequency transcranial ultrasound stimulation group and combined group(electroacupuncture+low-frequency transcranial ultrasound stimulation),with eight rats in each group.Feeney weight-drop method was used to establish the animal model of traumatic brain injury.In the sham group,the bone window was only opened without impact.Interventions were started at 1 day after modeling.Electroacupuncture in the electroacupuncture group,low-frequency transcranial ultrasound stimulation in the low-frequency transcranial ultrasound stimulation group,and electroacupuncture+low-frequency transcranial ultrasound stimulation in the combined group were performed for days in total.The modified neurological severity scale score for assessing rats'neurological deficits was performed at 8 hours after modeling.The percentage of spontaneous alternation behavior in the Y-maze was measured at 7 days after modeling.Then,the electroencephalographic signals were collected and electroencephalographic data of α,β,θ,and δ waves were extracted by fast Fourier transform,and the value of oscillation amplitude and energy ratio were calculated in α,β,θ,and δ waves,as well as the Lempel-Ziv complexity and sample entropy. RESULTS AND CONCLUSION:Compared with the sham group,the modified neurological severity scale scores in the model group,electroacupuncture group,low-frequency transcranial ultrasound stimulation group and combined group were significantly increased at 8 hours after modeling(P<0.05).Compared with the sham group,the value of oscillation amplitude in δ wave and the value of δ energy ratio were significantly increased in the model group at 7 days after modeling,meanwhile the percentage of spontaneous alternation behavior in Y-maze,and the value of α/β energy ratio,Lempel-Ziv complexity,and sample entropy were significantly decreased(P<0.05).Compared with the model group,the value of oscillation amplitude in α and δ waves was significantly decreased in the combined group(P<0.05),while the value of α/β energy ratio was significantly increased(P<0.05)and the value of δ energy ratio was significantly decreased(P<0.05)in the electroacupuncture group,low-frequency transcranial ultrasound stimulation group and combined group.Compared with the electroacupuncture group and low-frequency transcranial ultrasound stimulation group,the value of δ energy ratio was significantly decreased in the combined group(P<0.05),while the percentage of spontaneous alternation behavior,the value of α/β energy ratio,the Lempel-Ziv complexity,and the sample entropy were significantly increased(P<0.05).To conclude,abnormal electroencephalographic signals can appear in rats with traumatic brain injury,while the electroacupuncture combined with low-frequency transcranial ultrasound stimulation can alleviate the abnormal electroencephalographic signals in rats,which suggests the electroencephalographic frequency domain value and nonlinear features can be used to assess the severity of traumatic brain injury.

BACKGROUND:With the continuous advancement of medical technology,stem cell therapy has been used to treat a variety of diseases,including amyotrophic lateral sclerosis. OBJECTIVE:To review the research progress of stem cell therapy for amyotrophic lateral sclerosis,and prospect the development trend of this field. METHODS:PubMed,China National Knowledge Infrastructure(CNKI),and WanFang Data were searched for articles published from 1995 to 2024 using the key words"amyotrophic lateral sclerosis,mesenchymal stem cells,neural stem/progenitor cells,pluripotent stem cells."A total of more than 1 700 articles were retrieved,and 58 articles were finally included in this review. RESULTS AND CONCLUSION:Amyotrophic lateral sclerosis is a neurodegenerative disease that affects lower motor neurons in the brainstem and spinal cord and upper motor neurons in the motor cortex.The related research of stem cells in the treatment of amyotrophic lateral sclerosis has become a research hotspot.In this review,we summarize the application of different types of stem cells in amyotrophic lateral sclerosis research,including mesenchymal stem cells,neural stem progenitor cells,and induced pluripotent stem cells,and evaluate the key points of preclinical research such as stem cell source,cell volume,stem cell modification methods,and drug delivery routes,which lays the foundation for the future application of stem cell therapy.

Objective:To summarized the clinical characteristics of intracranial germ cell tumors（iGCTs）in children, with the ultimate goal of facilitating early tumor identification and guiding the prompt selection of appropriate treatment strategies.Methods:A retrospective analysis was conducted on pediatric patients with primary iGCTs admitted to Beijing Tiantan Hospital Affiliated to Capital Medical University between March 2021 and June 2022. Patient age, gender, clinical manifestations, tumor marker levels in cerebrospinal fluid (CSF) and blood, imaging features, and histopathological examination results were meticulously collected and statistically analyzed.Results:A total of 126 pediatric patients with iGCTs were included in the study, of which 86 cases (68.3%) were male,and 40 cases (31.7%) were female.The average age was (10.0 ± 3.5) years old. The mean age of onset was found between 6~14 years old(80.1%), with a male-to-female ratio of 2.2:1.The tumors were predominantly located in the sellar region (30.2%), basal ganglia (23.8%), and pineal region (19.8%). Notably, there were distinct differences in tumor location across different age groups: pineal region tumors were most prevalent in preschool children (71.4%), basal ganglia tumors were more common in school-age children (41.9%), and sellar region involvement was highest among adolescent patients(44.8%). Based on molecular marker analysis and biopsy diagnosis, 79 cases were classified as germinoma, 3 as teratoma, 2 as yolk sac tumor, 1 as choriocarcinoma, and 41 as mixed germinoma.All children underwent head CT and MRI examinations. Among them, 99 cases showed high-density lesions on CT,while 27 cases showed mixed density,including 39 cases of calcification and 35 cases of hydrocephalus.MRI revealed atrophy of the cerebral peduncle, caudate nucleus head, or cerebral cortex in 38 cases, involvement of the basal ganglia in 33 cases, and midbrain involvement in 5 cases.Blood β-human chorionic gonadotropin (β-HCG) and alpha-fetoprotein (AFP) levels were examined in all patients, while CSF tumor marker levels were analyzed in 103 cases. There were 76 cases with elevated β-HCG in blood and/or cerebrospinal fluid, and 24 cases with elevated AFP in blood and/or CSF.Additionally, all 86 male patients underwent genital ultrasound, revealed testicular microlithiasis in 12 cases and testicular cysts in 6 cases.Conclusion:The clinical presentation of iGCTs in pediatric patients exhibits significant heterogeneity in terms of epidemiology, classification, tumor location, and molecular markers. Notably, CSF β-HCG and AFP levels are equally crucial diagnostic indicators alongside blood tumor markers.Histological examination should be performed as early as possible in clinically suspected cases with negative tumor markers. Clinicians should remain vigilant for early imaging negative potential cases. In addition, male children with testicular microlithiasis or cysts should be closely followed up.

Interventional therapy promises a novel treatment for muscle invasive bladder cancer(MIBC),but the long-term effect is limited,and combination therapy is necessary for MIBC.Cryoablation kills tumors by freezing tissue with ultra-low temperature,but its safety and efficacy for MIBC remains unclear.The research progresses in cryoablation for bladder cancer animal models and human MIBC were reviewed in this article.

Objective:This study aims to provide insights into the clinical features of anti-melanoma differentiation-associated protein-5(MDA5)-positive dermatomyositis (MDA5-DM) patients with fatal outcomes, leveraging pathogenic microbiota metagenomic analysis, to guide the clinical assessment and treatment choices.Methods:From January 2020 to August 2023, deceased patients diagnosed with MDA5-DM were identified at the Department of Rheumatology and Immunology, the Second Affiliated Hospital of Xi ′an Jiaotong University. Clinical data were retrospectively collected and analyzed using Mann Whitney U test and Fisher ′s exact test to summarize risk factors and treatment assessment for MDA5-DM patients with fatal outcomes. Results:①The proportion of male patients was higher than females among MDA5-DM patients with fatal outcomes, which differed from the incidence pattern, possibly associated with smoking and gender proportions (6/11 vs. 0/7, P=0.037). ②94%(17/18) patients presented initially with elevated ferritin levels [(1 350±942)ng/ml] and CRP [(47±36)mg/L]. ③All patients (18/18) exhibited early involvement of the upper lung lobes, including multiple nodules in 9/18, ground-glass opacities in 5/18, and solitary nodules in 4/18. ④Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid was negative in 4/16 cases, with cytomegalovirus and pneumocystis jirovecii being the most commonly detected pathogens in 5/16 cases each. ⑤89%(16/18) of patients continued to have lymphocyte counts persistently <0.5×10 9/L irrespective of treatment. Conclusion:Smoking may have adverse effects on male MDA5 patients. Early involvement of the upper lobe of the lungs is more common in MDA5 antibody positive deaths, and persistent lymphocyte depletion is an important factor in poor response. Enhancing mNGS analysis of bronchoalveolar lavage fluid and vigilance towards cytomegalovirusand Pneumocystis jirovecii could provide valuable clinical guidance.

Objective:To investigate the incidence, risk factors, and outcomes of falls among the elderly community population in Beijing.Methods:A cross-sectional survey was conducted using stratified multistage random sampling to select urban and rural residents aged 65 years and older in Beijing. Mortality data was collected after the baseline survey for 5 years. The incidence of falls was weighted based on the composition ratios of age and gender from the 2010 Nation-wide Population Census of Beijing. A logistic regression model was used to analyze the impacts of demographic sociology of common chronic diseases on fall occurrence. The Cox proportional hazards regression model was used to analyze the fall and 5-year survival association.Results:A total of 2 968 participants completed the questionnaire, at cross-sectional survey, with an average age of (73.2±6.0) years, and 1 581 (53.8%) participants were female. Three hundred and sixty-one individuals experienced a fall within the past year. Among those who fell, 64 (17.7%) fell twice, and 95 (26.6%) fell three or more times. Of them, 14.4% (52) had post-fall fractures, with the wrist, knee, and hip being the most common fracture sites, accounting for 25.0%, 17.3%, and 15.4%, respectively. The weighted fall incidence was 12.4% (95% CI: 11.2%-13.5%). Aging, being female, and living in rural areas were more likely to fall. Logistic regression analysis showed that after adjusting for age, gender, and urban-rural status, the risk of falls for those living alone ( OR=1.48, 95% CI: 1.08-2.04) or living with children/grandchildren ( OR=1.51, 95% CI: 1.15-1.97) were significantly higher than those living with their spouse. In addition, the risk of falls was elevated significantly among the elderly with hypertension, diabetes, stroke, dementia, depression status, urinary incontinence, arthritis, insomnia, vision, and hearing loss, dependence on activities of daily living (ADL), general and poor self-rated health (SRH). The Cox proportional hazard regression model revealed that the 5-year risk of death increased by 65% ( HR=1.65, 95% CI: 1.29-2.11) for those who experienced a fall, which increased with fall frequency. This elevated risk persisted after adjusting for chronic conditions, ADL, and SRH. Conclusions:Ageing, female, living in rural regions, having common chronic diseases, dependence on ADL, general and poor SRH, living alone or living with children/grandchildren were associated with the elevated fall risk. The occurrence of fall was seasonal. The most common short-term adverse consequence after a fall was fractures, while the long-term effect was an increased risk of death.

Objective:To evaluate the clinical efficacy of a novel reduction device in the treatment of A3N0/1 thoracolumbar fracture using navigation-assisted techniques.Methods:A retrospective analysis was conducted on 45 patients (29 males, 16 females; mean age 40.67±16.11 years, range 24-57) with thoracolumbar fractures who underwent fracture reduction and pedicle screw fixation via the Wiltse approach at Zhengzhou Orthopaedic Hospital between January 2022 and January 2023. Injury levels included: T 10 in 2 cases, T 11 in 5 cases, T 12 in 13 cases, L 1 in 20 cases, L 2 in 3 cases, L 3 in 2 cases. All patients underwent fracture reduction via the Wiltse approach using the spinal fracture reduction instrument for vertebral body reduction. Among them, 20 patients received O-arm navigation-assisted internal fixation and vertebral reduction (O-arm group), while 25 received C-arm fluoroscopy-guided internal fixation and vertebral reduction (C-arm group). Operative time, intraoperative blood loss, vertebral reduction time using the instrument, first-time screw placement success rate, screw placement accuracy, and complications were compared. Mid-vertebral body height ratio (MVBHr), local Cobb angle of the fractured vertebra, visual analogue scale (VAS) score, and Oswestry disability index (ODI) were compared preoperatively, at 1 week postoperatively, 3 months postoperatively, and final follow-up. Results:All surgeries were successfully completed in both groups. Operative time was significantly shorter in the O-arm group (106.8±14.4 min) than in the C-arm group (119.1±16.4 min, P<0.05). All patients were followed up for a mean duration of 15.9±3.9 months (range 12-20 months). Vertebral reduction time was significantly shorter in the O-arm group (11.0±2.2 min) than in the C-arm group (20.4±5.7 min, P<0.05). The first-time screw placement success rate was significantly higher in the O-arm group (100%) than in the C-arm group (95.3%, P<0.05). Screw placement accuracy (Grade I) was significantly higher in the O-arm group (117 screws, 97.5%) than in the C-arm group (136 screws, 90.7%, P<0.05). No cases of wrong-level surgery, infection, or spinal cord/nerve injury occurred. Both groups showed significant improvements in MVBHr, Cobb angle, VAS, and ODI at all postoperative time points compared to preoperative values ( P<0.05). At final follow-up, the O-arm group demonstrated significantly better outcomes than the C-arm group in MVBHr (90.6%±4.5% vs. 86.4%±6.9%, P<0.05), Cobb angle (7.6°±1.8° vs. 10.1°±3.2°, P<0.05), VAS (1.3±0.4 vs. 1.7±0.6, P<0.05), and ODI (4.6%±1.9% vs. 7.7%±2.0%, P<0.01). Conclusion:O-arm navigation-assisted intrasegmental push reduction for A3N0/1 type thoracolumbar fractures demonstrates advantages including faster and more accurate screw placement, precise reduction with improved outcomes, and significant postoperative pain relief.

Liver cancer is one of the leading causes of cancer-related mortality worldwide.The treatment paradigm of HCC is shifting from traditional"single-modality resection"toward an integrated model featuring"multi-strategy synergy".In recent years,neoadjuvant therapies,particularly those combining interventional approaches with immunotherapy before surgery had attracted much attention.The current evidences and emerging trends of interventional and immune-driven strategies in neoadjuvant therapy for liver cancer were reviewed in this article.