BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.

BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.

With the acceleration of global population aging， the assessment and prediction of brain aging have become an important research direction in neuroscience. Brain age， as an indicator for measuring the biological age of the brain， can be used to assess individual cognitive function and predict the risk of neurodegenerative diseases. Neuroimaging techniques can reveal the structure and functional state of the brain， providing an important basis for brain age prediction. The hypoxic environment at high altitudes may accelerate brain aging， and its neuroimaging features provide a unique perspective for assessing brain aging. This article reviews the latest research advances in brain aging and brain age prediction under a high-altitude hypoxia environment， with a focus on the construction of brain age prediction models， the application of sMRI/DTI/fMRI， and the impact of high-altitude hypoxia on brain structure， function， and mechanisms， in order to provide a reference and directions for future research.
Neuroimaging

Objective To compare the biomechanical characteristics of novel retrograde intramedullary nail,common femoral retrograde intramedullary nail,and medial femoral condyle locking plate for treating distal femur type A fractures by finite element analysis,and study the advantages of retrograde intramedullary nail on medial femoral condyle.Methods A novel retrograde intramedullary nail on medial femur condyle was designed.CT scan was performed on lower limb bones of a male volunteer,and a three-dimensional(3D)model of the femur was established.The model was then segmented to create models of distal femur type A2 and A3 fractures.The 3D models of internal fixator were established.The small and standard retrograde intramedullary nail on medial femoral condyle,common femoral retrograde intramedullary nail,locking plate on medial femoral condyle were used for internal fixation on A2 type fracture.A3 type fracture was fixed with one of the above internal fixators combined with lateral condylar plate respectively.The 600 N axial load and 4 N·m torsional load were applied to the models.The displacement and stress of femurs,the displacement and stress of internal fixators,the micro-momentum between the internal fixator and the bone,the relative displacement of the two fracture broken ends were observed in each group.Results Among the A2 and A3 type fractures under axial loads,the correponding standard group and corresponding standard combined group had the smallest peak displacement and peak stress of internal fixation.Among the A2 and A3 type fractures under torsional loads,the correponding standard group and corresponding standard combined group had the smallest peak displacement of the femur and internal fixation.The relative displacement of the two broken ends in the standard combined group was the smallest.Conclusions Compared with femoral medial condylar locking plate and common retrograde intramedullary nail,this novel retrograde intramedullary nail on medial femur condyle has a mechanical advantage of reducing stress concentration and reducing the risk of internal fixation failure,and it can be used alone for distal femur type A2 fracture,or in combination with the lateral condylar plate to fix distal femur type A3 fracture.

Objective To compare the biomechanical characteristics of novel retrograde intramedullary nail,common femoral retrograde intramedullary nail,and medial femoral condyle locking plate for treating distal femur type A fractures by finite element analysis,and study the advantages of retrograde intramedullary nail on medial femoral condyle.Methods A novel retrograde intramedullary nail on medial femur condyle was designed.CT scan was performed on lower limb bones of a male volunteer,and a three-dimensional(3D)model of the femur was established.The model was then segmented to create models of distal femur type A2 and A3 fractures.The 3D models of internal fixator were established.The small and standard retrograde intramedullary nail on medial femoral condyle,common femoral retrograde intramedullary nail,locking plate on medial femoral condyle were used for internal fixation on A2 type fracture.A3 type fracture was fixed with one of the above internal fixators combined with lateral condylar plate respectively.The 600 N axial load and 4 N·m torsional load were applied to the models.The displacement and stress of femurs,the displacement and stress of internal fixators,the micro-momentum between the internal fixator and the bone,the relative displacement of the two fracture broken ends were observed in each group.Results Among the A2 and A3 type fractures under axial loads,the correponding standard group and corresponding standard combined group had the smallest peak displacement and peak stress of internal fixation.Among the A2 and A3 type fractures under torsional loads,the correponding standard group and corresponding standard combined group had the smallest peak displacement of the femur and internal fixation.The relative displacement of the two broken ends in the standard combined group was the smallest.Conclusions Compared with femoral medial condylar locking plate and common retrograde intramedullary nail,this novel retrograde intramedullary nail on medial femur condyle has a mechanical advantage of reducing stress concentration and reducing the risk of internal fixation failure,and it can be used alone for distal femur type A2 fracture,or in combination with the lateral condylar plate to fix distal femur type A3 fracture.

Purpose In this study,tract-based spatial statistical analysis was used to analyze the diffusion tensor imaging(DTI)data of breast cancer patients after chemotherapy,to observe the changes of white matter microstructure after chemotherapy and their correlation with neuropsychological cognitive test results,and to provide imaging markers for the evaluation of brain injury after chemotherapy for breast cancer.Materials and Methods A total of 29 patients with breast cancer before chemotherapy treatment and 30 patients with breast cancer after chemotherapy treatment were enrolled in the study from November 2022 to June 2023 in the Affiliated Taizhou People's Hospital of Nanjing Medical University.Neuropsychological cognitive test[Montreal cognitive assessment(MoCA),mini-mental state examination(MMSE)]and whole brain DTI examination were respectively performed in the two groups.Fractional anisotropy(FA)and mean diffusivity(MD)were used to compare the differences between the two groups at the structural level.The correlation between the results of DTI and neuropsychological cognitive test was analyzed.Results Compared with the patients with breast cancer before chemotherapy treatment group,patients with breast cancer after chemotherapy treatment group had decreased FA values in bilateral anterior corona radiata,superior corona radiata,corpus callosum body and genu,left posterior thalamic radiation,left external capsule,bilateral superior longitudinal fasciculus,and increased MD values in bilateral anterior corona radiata,superior corona radiata,right posterior corona radiata,corpus callosum body and genu,right posterior thalamic radiation,bilateral superior longitudinal fasciculus.The FA values of left superior corona radiata(r=0.302)and left external capsule(r=0.370)were positively correlated with MMSE results,and the FA values of left outer capsule(r=0.328)were positively correlated with MoCA results(all P<0.05).The MD values of corpus callosum body(r=-0.343)and genu(r=-0.378),left superior corona radiata(r=-0.311),right posterior corona radiata(r=-0.376),right posterior thalamic radiation(r=-0.341)and right superior longitudinal fasciculus(r=-0.392)were negatively correlated with MMSE results(all P<0.05).Conclusion In the chemotherapy group,FA and MD values in multiple brain regions are abnormal,and there is a certain correlation between FA and MD values in some brain regions and neurocognitive test results.The changes of FA and MD values in different brain areas may be potential imaging markers of the abnormal white matter microstructure in breast cancer patients treated with chemotherapy.

Objective:To evaluate the short-term and long-term outcomes of patients with locally advanced low rectal cancer who achieved clinical complete response (cCR) or near-clinical complete response (near-cCR) after neoadjuvant chemoradiotherapy (nCRT) and then underwent local excision.Methods:This was a descriptive case series study. Clinical data of patients with low rectal cancer who received neoadjuvant therapy, achieved cCR or near-cCR, underwent local excision, and had complete postoperative follow-up data were retrospectively analyzed. The study period was from May, 2015 to October, 2024, and the patients were treated at Fujian Medical University Union Hospital. Indications for local excision in this study were as follows: pathologically confirmed rectal adenocarcinoma, with the lower edge of the tumor ≤ 6 cm from the anal verge; maximum diameter of the lesion ≤ 2 cm after nCRT; no regional lymph node metastasis detected by transrectal endoscopic ultrasound (ERUS), pelvic magnetic resonance imaging (MRI), or positron emission tomography-computed tomography (PET-CT) after nCRT; MRI showing fibrosis of the primary lesion with a small amount of high signal on diffusion-weighted imaging (DWI), consistent with ymrT0-1 stage; serum carcinoembryonic antigen level within the normal range (< 5 μg/L) after nCRT; complicated with severe underlying diseases such as cardiovascular and cerebrovascular diseases and assessed as unable to tolerate radical surgery through comprehensive evaluation; and signed informed consent for local excision. The contraindications were: colonoscopic pathology indicating poorly differentiated adenocarcinoma or signet ring cell carcinoma; suspected lateral lymph node metastasis before neoadjuvant therapy; patients with residual lesions exceeding 3 cm in range after treatment. A total of 153 patients were included in this study, including 84 males and 69 females. The median age was 62 years, and the median distance from the tumor to the anal verge after neoadjuvant therapy was 4.0 cm. The short-term efficacy indicators of this study included postoperative complications of local excision and postoperative pathological results, and the long-term efficacy indicators included oncological prognosis (3-year cumulative local recurrence rate, 3-year cumulative distant metastasis rate, 3-year progression-free survival, and 3-year overall survival) and anal function at 1 year after surgery evaluated using the Low Anterior Resection Syndrome (LARS) scale where the total score is 42 points such that 0-20 points indicate no LARS, 21-29 points indicate mild LARS, and 30-42 points indicate severe LARS.Results:Postoperative pathology showed 122 cases (79.7%) of ypT0 stage, 10 cases (6.5%) of ypT1 stage, 18 cases (11.8%) of ypT2 stage, and 3 cases (2.0%) of ypT3 stage. The incidence of surgery-related complications was 42.5% (65/153), and the main complications included perianal pain (39.9%, 61/153), intestinal wall incision dehiscence (21.6%, 33/153), and intestinal wall incision infection (18.3%, 28/153). The proportion of patients who received hypofractionated radiotherapy before surgery and developed intestinal wall incision dehiscence was 65.2% (15/23), which was higher than that in the conventional long-course (13.6%, 16/118) and short-course radiotherapy groups (16.7%,2/12) (χ 2=30.55, P<0.001); of the 20 patients who received additional immunotherapy before surgery, 13 developed intestinal wall incision dehiscence was 65.0%, which was higher than that in the group without additional immunotherapy [15.0%(20/133),χ 2=25.66, P<0.001]. The median follow-up time of the entire group was 35.4 months. During the follow-up period, there were 9 cases of postoperative local recurrence, with a 3-year cumulative local recurrence rate of 7.9% and 5 cases of distant metastasis, with a 3-year cumulative distant metastasis rate of 5.0%. The 3-year progression-free survival rate was 89.0%, and the 3-year overall survival rate was 95.9%. At 1 year after surgery, 10 cases (10.5%, 10/95) had severe anal dysfunction, and the median LARS score of the entire group was 5.0 (range: 0-41.0) points. Conclusions:For patients with locally advanced low rectal cancer who achieve cCR or near-cCR after neoadjuvant therapy, local excision results in favorable oncological prognosis and anal function preservation effects; however, the incidence of complications is relatively high.

The integration of multi-source data and the establishment of early warning indicator systems constitute pivotal elements for advancing surveillance and early warning capacities in respiratory infectious diseases. Given the multifaceted transmission mechanisms and complex contributing factors inherent in respiratory infectious diseases, surveillance datasets and associated early warning indicators demonstrate notable heterogeneity and sophisticated interrelationships. Furthermore, as surveillance and early warning requirements significantly vary across diverse epidemiological scenarios, accurate assessment of the value and applicability of distinct data types and indicators is imperative. This paper systematically reviews and synthesizes recent advancements in surveillance data and early warning indicators for respiratory infectious diseases, drawing on both domestic and international research. Particular attention is dedicated to analyzing the applicability and efficacy of various data types and indicators within multiple practical contexts, aiming to provide robust theoretical frameworks and methodological guidance to facilitate the development of resilient and efficient surveillance and early warning systems for respiratory infectious diseases.

The prevention and control of emerging and reemerging infectious diseases are crucial for national biosecurity, and surveillance and reporting of pneumonia of unknown etiology are main ways for the early detection of these diseases and mitigation of their severity. This paper summaries the surveillance methods for pneumonia of unknown etiology and emerging and reemerging infectious diseases globally, indicating that such surveillance is mainly conducted based on hospital. Western countries primarily combine active and passive surveillance while utilizing artificial intelligence technology to rapidly identify cases. China mainly use passive surveillance based on the surveillance system for pneumonia of unknown etiology, with the function of early warning in the identification of emerging infectious diseases, such as avian influenza. However, with the improvement in the surveillance system operation, the overlap with other surveillance disease systems, such as influenza, has occurred, and the improvements in case definition and operational protocol are needed. It is recommended to improve the specificity of the case definition, strenthen training in hospital staff, inclduing clinical workers and office workers, and formulate incentive mechanisms. It is necessary to emphasize the responsibility of clinicians as the main force for the detection and reporting of pneumonia of unknown etiology and emerging infectious diseases, improve the appilication of artifical intelligent technique and conduct multi-source surveillance, such as third-party testing.

With the change of infectious disease incidence pattern and the development of related technologies, progresses have been made in the research of infectious disease epidemiology. In recent years, due to the change in the requirements of infectious disease prevention and control, the research focus has expanded from common infectious diseases to diseases which have been eliminated or might be eliminated, as well as emerging and re-emerging infectious diseases. Infectious disease data has been characterized by multiple sources and modalities. Along with the rapid development of pathogen detection methods, infectious disease surveillance has shifted from a single disease-targted one to a comprehensive one. Moreover, novel technologies such as multi-omics and artificial intelligence have been applied in infectious disease epidemiology research. The international cooperation in this field has become increasingly crucial, and the revision of the International Health Regulations and the negotiation of pandemic agreement will have a profound impact. In the future, infectious disease epidemiology research will develop with more powerful tools to improve its capabilities.