BACKGROUND:Bilateral-sagitta-split-ramus-osteotomy (BSSRO) has become a conventional method to correct facial deformities, and the finite element method is a significant way to study biomechanics of the mandible and temporomandibular joint (TMJ) after BSSRO. OBJECTIVE: To establish a precise and high simulation model of mandible containing TMJ after BSSRO with internal fixation, which is the base to study the biomechanics of the mandible and TMJ after BSSRO. METHODS: Spiral CT scan was used to get the data of DICOM that were input into MIMICS to establish the three-dimensional model of the mandible. The three-dimensional model was wrapped into a single closed shel for mesh generation and conversion in ANSYS. Then, the model was input into the ANSYS software for temporomandibular joint reconstruction and simulation of BSSRO and internal fixation. RESULTS AND CONCLUSION: The three-dimensional finite element model of mandible containing TMJ after BSSRO was established using MIMICS and ANSYS. This model had biological similarity and geometric similarity in comparison with the human tissues. The model could undergo various internal fixations through antedisplacement, retroposition and rotational movement of the distal end. Based on different experimental purposes, the established model can apply a load to al parts to study changes in stress and displacement of different tissues after BSSRO and internal fixation, and it also can be used to study the effect of different fixation materials on the rear stability after internal fixation.

Objective To investigate the value of blood oxygenation level dependent(BOLD)fMRI in assessing the functional changes of the lumbar dorsal extensor muscles before and after exercise in healthy young people.Methods The changes of the R2*value of lumbar dorsal extensor group in 30 healthy young volunteers(15 males and 15 females)before and after exercise was prospectively studied.BOLD-fMRI scans were performed on healthy young volunteers before and after exercise, the exercise mode was to perform the upper body flexion and extension movement with a simple Rome stool.The scanned images were processed and analyzed, the cross-sectional area and R2* value of the lumbar dorsal extensor muscles (including the multifidus,the longissimus and the iliocostalis)were measured at the upper margin of the L3 and L4 vertebral body before and after exercise.The paired t test was used to compare CSA and R2*values of muscles before and after loading. The CSA and R2* value of different muscles in different sides were compared by independent sample t test. Pearson correlation analysis was used to analyze the relevance between CSA and R2* in muscle before and after exercise. Results After exercise, the R2* values of multifidus,longissimus and iliocostalis at the upper margin of the L4 vertebral body were[(39.2±8.6),(38.9± 7.7),(41.6±7.8)]Hz,significantly lower than before exercise[(46.1±6.9),(45.3±6.2),(46.0±6.7)]Hz(P<0.01);the changes of R2*values of the muscles between the left and right sides before and after the movements were not statistically significant(P>0.05).The R2*values of longissimus and iliocostalis at the upper margin of the L3 vertebral body were[(44.2±9.1),(46.6±9.3)]Hz,significantly lower than before exercise[(48.6±7.2),(49.7± 6.8)]Hz (P<0.01), but the R2* values of multifidus after loading was (43.9 ± 9.0)Hz, there was no statistical difference compared with before exercise (46.8 ± 6.6)Hz (P>0.05);there was a significant difference in the changes of R2*value before and after the movement between the left and right side of iliocostalis(P<0.05).A significant negative correlation between CSA and R2*value was found in the iliocostalis on the right side at the upper margin of L3 vertebral body and in the multifidus on the left side at the upper margin of L4 vertebral body,and the correlation coefficients were (-0.697,-0.616).Conclusion BOLD-fMRI can be a new way to assess the functional changes of the lumbar dorsal extensor group before and after exercise.

OBJECTIVETo report on prenatal diagnosis and follow up of two patients with paternal uniparental disomy of chromosome 6 (pUPD6).

METHODSFetal cells were subjected to in situ culturing and G-banded chromosomal analysis. DNA samples of the fetuses and their parents were also analyzed with single nucleotide polymorphism microarray (SNP array).

RESULTSBoth fetuses had a normal male karyotype. SNP array analysis showed both have carried pUPD6.

CONCLUSIONpUPD6 can lead to transient neonatal diabetes mellitus type 1. Homozygous status of recessive mutations, disorder of gene imprinting, and its influence on placental function are the main factors to be considered during prenatal diagnosis and genetic counseling for pUPD6.

Objective To explore the value of T2-mapping imaging in assessment of lumbar dorsal extensors group (multifidus,longissimus and iliocostalis) function before and after exercises in healthy volunteers.Methods Totally 50 healthy young volunteers underwent T2-mapping imaging before and after exercises.T2 value and cross-section area (CSA) of multifidus,longissimus and iliocostalis were measured at the level of L3 and 14 superior border.Differences of CSA and T2 value were compared between left and right side muscles before and after exercises.The correlation between CSA difference and T2 difference before and after exercises was analyzed.Results At the level of L3 and L4 superior border,CSA and T2 value of bilateral multifidus,longissimus and iliocostalis increased after exercises (all P＜0.05).At the level of L3 superior border,CSA after exercises and CSA difference of left multifidus were higher than those of right side (all P＜0.05).Before exercises,there were statistical differences of T2 values on left and right side of longissimus and iliocostalis at the level of L3 superior border and the longissimus at the level of L4 superior border (all P＜0.05).Positive correlations were found between CSA difference and T2 difference on bilateral iliocostalis at the level of L3 and L4 superior border,as well as on bilateral multifidus at the level of L4 superior border (all P ＜0.05).Conclusion T2-mapping imaging can be used to assess the activity state of lumbar dorsal extensors group before and after exercises.

Objective:To explore the classification performance of combined model constructed from CT signs combined with radiomics for discriminating COVID-19 pneumonia and other viral pneumonia.Methods:The clinical and CT imaging data of 181 patients with viral pneumonia confirmed by reverse transcription-polymerase chain reaction in 15 hospitals of Yunnan Province from March 2015 to March 2020 were analyzed retrospectively. The 181 patients were divided into COVID-19 group (89 cases) and non-COVID-19 group (92 cases), which were further divided into training cohort (126 cases) and test cohort (55 cases) at a ratio of 7∶3 using random stratified sampling. The CT signs of pneumonia were determined and the radiomics features were extracted from the initial unenhanced chest CT images to build independent and combined models for predicting COVID-19 pneumonia. The diagnostic performance of the models were evaluated using receiver operating characteristic (ROC) analysis, continuous net reclassification index (NRI) calibration curve and decision curve analysis.Results:The combined models consisted of 3 significant CT signs and 14 selected radiomics features. For the radiomics model alone, the area under the ROC curve (AUC) were 0.904 (sensitivity was 85.5%, specificity was 84.4%, accuracy was 84.9%) in the training cohort and 0.866 (sensitivity was 77.8%, specificity was 78.6%, accuracy 78.2%) in the test cohort. After combining CT signs and radiomics features, AUC of the combined model for the training cohort was 0.956 (sensitivity was 91.9%, specificity was 85.9%, accuracy was 88.9%), while that for the test cohort was 0.943 (sensitivity was 88.9%, specificity was 85.7%, accuracy was 87.3%). The AUC values of the combined model and the radiomics model in the differentiation of COVID-19 group and the non-COVID-19 group were significantly different in the training cohort ( Z=-2.43, P=0.015), but difference had no statistical significance in the test cohort ( Z=-1.73, P=0.083), and further analysis using the NRI showed that the combined model in both the training cohort and the test cohort had a positive improvement ability compared with radiomics model alone (training cohort: continuous NRI 1.077, 95 %CI 0.783-1.370; test cohort: continuous NRI 1.421, 95 %CI 1.051-1.790). The calibration curve showed that the prediction probability of COVID-19 predicted by the combined model was in good agreement with the observed value in the training and test cohorts; the decision curve showed that a net benefit greater than 0.6 could be obtained when the threshold probability of the combined model was 0-0.75. Conclusion:The combination of CT signs and radiomics might be a potential method for distinguishing COVID-19 and other viral pneumonia with good performance.

Objective:To explore the repairing effects of 3D-printed nano-β-tricalcium phosphate (β-TCP) scaffolds loaded with vancomycin and bone morphogenetic protein-2 (BMP-2) for seawater -soaked tibial bone defects in rabbits. Methods:A total of 27 male New Zealand White rabbits were assigned to the normal group using a random number table method, with each group consisting of 9 rabbits. The rabbit tibial bone defect model was created using the osteotomy surgical method. Eight hours after operation, the wounds in the control group and seawater group were immersed in seawater for 2 hours, and those in the normal group were not immersed. After an observation period of 5-7 days, no significant redness or purulent discharge was observed in the wound appearance, then debridement was performed followed by corresponding implantations: the control group with gelatin sponges loaded with vancomycin and BMP-2, and the other two groups with 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2. After filling the bone defects with the respective materials, all groups underwent layer-by-layer suturing of the wound, followed by disinfection with iodine and injection of gentamicin to prevent infection. The affected limbs were then immobilized using a plaster cast. The affected limbs were imaged using anteroposterior X-ray at 4, 8 and 16 weeks after operation, and the repair effects were evaluated using the Lane-Sandhu X-ray scoring system. At 16 weeks after operation, the bone defect tissues were collected for HE staining to observe bone tissue growth.Results:At 4 weeks after operation, the Lane-Sandhu X-ray score in the control group was significantly lower than that in the normal group [(2.8±1.1)points vs. (1.1±0.9)points] ( P<0.05), and that in the seawater group [(2.2±1.0)points] was not significantly different from those in the other two groups (all P>0.05). At 8 weeks after operation, the seawater group [(6.1±0.9)points] and the control group [(2.8±1.0)points] exhibited lower Lane-Sandhu X-ray score compared to the normal group [(8.2±1.0)points] (all P<0.05), and the seawater group showed a higher score compared to the control group ( P<0.05). At 16 weeks after operation, the control group [(3.8±1.0)points] exhibited a lower Lane-Sandhu X-ray score compared to the normal group [(10.0±1.3)points] and the seawater group [(9.3±1.2)points] (all P<0.05), while no significant difference was noted between the latter two ( P>0.05). At 16 weeks after operation, histological observations revealed varying degrees of bone tissue formation in three groups, with the normal group showing the best bone defect repair effect, followed by the seawater group. Conclusion:The 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2 are effective for the treatment of seawater -soaked bone defects, which can promote bone tissue repair.

The adverse health effects of air pollution remains a daunting public health problem globally. The research of the health effects of air pollution provides important evidence for ambient air quality standard establishments and air pollution interventions. In recent years, causal inference has been gradually introduced into the observational study of environmental epidemiology, which provides more statistical method options for the study of causal relationships between air pollution and population health effects. Controlling confounders in observational studies is a major challenge for causal inference. This study introduces the causal inference methods for the identification and control of confounding factors currently used in the study of air pollution and population health effects, in order to provide methodological reference and basis for the causal inference study of air pollution and population health effects in China.

The adverse health effects of air pollution remains a daunting public health problem globally. The research of the health effects of air pollution provides important evidence for ambient air quality standard establishments and air pollution interventions. In recent years, causal inference has been gradually introduced into the observational study of environmental epidemiology, which provides more statistical method options for the study of causal relationships between air pollution and population health effects. Controlling confounders in observational studies is a major challenge for causal inference. This study introduces the causal inference methods for the identification and control of confounding factors currently used in the study of air pollution and population health effects, in order to provide methodological reference and basis for the causal inference study of air pollution and population health effects in China.

Objective To compare the clinical efficacy and imaging results of uniportal interlaminar endoscopy(UIE)and unilateral biportal endoscopy(UBE)for the treatment of lumbar disc herniation.Methods The clinical information for 50 patients diagnosed with lumbar disc herniation was collected,and treated by UIE endoscopic surgery and UBE endoscopic surgery in the The First People's Hospital of Hefei city from March 2021 to October 2022 were retrospectively analyzed.The patients were divided into two groups,UIE group and the UBE group.Perioperative indexes including incision length,operation time,intraoperative blood loss,and surgical complications,clinical efficacy indexes including VAS scores of low back pain and leg pain before surgery,3 days after surgery,3 months after surgery,6 months after surgery,and 12 months after surgery,ODI scores of dysfunc-tion index,and imaging results including spinal canal area,vertebral space height,before surgery and 1 year after surgery were recorded and compared between the two groups.Results Both groups completed the procedure and were followed up for 12～18 months,with an average of 15 months.1 case was dural injury,no nerve root injury,and no nerve root symptoms during the follow-up.The symptoms of lumbar and leg pain were all relieved in both groups after the procedure.The UBE groups hawed larger surgical incisions,more intraoperative blood loss,and shorter operative time compared to the UIE group(P＜0.05,respectively).Both groups had significant develop-ments in the VAS scores,ODI scores of back,and leg pain at 3 days,3 months,6 months,and 12 months after the operation(all P＜0.05).The UIE group showed significant developments in the VAS scores and ODI scores of back and leg pain at 3 days and 3 months after the operation,as compared to the UBE group(P＜0.05).The imaging analysis did not showed significant changes in the height of intervertebral space and the angle of lumbar lordosis,but a significantly larger increase in the dural sac area in both groups one year after the procedure,and the UBE group had even a larger increase than the UIE group(P＜0.05).Conclusion Both UIE and UBE have good clinical efficacy and imaging results in the treatment of lumbar disc herniation via interlaminal approach.However,the UIE group is superior to the UBE group in terms of the operation time,intraoperative blood loss,postoperative VAS score of low back pain as well as the decompression effectiveness.

Objective To investigate the effects of different extracorporeal membrane oxygenation(ECMO)bypass modes on the prognosis of patients with combined pulmonary fibrosis and emphysema(CPFE)during lung transplantation.Methods A retrospective analysis was conducted on 44 CPFE patients who underwent lung transplantation,and they were divided into the venous-venous ECMO(VV-ECMO)group(30 cases)and the venous-arterial ECMO(VA-ECMO)group(14 cases).The preoperative,intraoperative,postoperative and follow-up related indicators of two groups were compared.Results Compared with the VV-ECMO group,the patients in the VA-ECMO group were younger,had higher pulmonary artery pressure before surgery,fewer posterolateral incision types,longer operation times,and higher incidence of postoperative bronchopleural fistula(all P<0.05).The pulmonary artery pressure decreased after surgery in both groups,with a greater decrease in the VA-ECMO group(P<0.05).There was no statistically significant difference in postoperative survival rates between the two groups(P>0.05).Conclusions Both VA-ECMO and VV-ECMO are safe and effective in lung transplant patients with CPFE.The bypass mode has no significant impact on the short and medium-term prognosis of the patients.VA-ECMO is more suitable for patients with higher preoperative pulmonary artery pressure.