Objective To compare H_p(3) calibration with a homemade (A) thermoluminescent dosimeter (TLD) and an imported (B) TLD in a standard X-ray RQR radiation field, to explore the different responses of A and B, and to provide foundation for the calibration of H_p(3). Methods A column mode was selected. H_p(3) calibration was performed using A and B in a standard X-ray RQR radiation field in the Secondary Standard Dosimetry Laboratory, National Institute for Radiological Protection, China Center for Disease Control and Prevention. Angle response, energy response, and linear response were calibrated with RQR4 (60 kV), RQR7 (90 kV), and RQR9 (120 kV), respectively. Results In terms of angle response, the calibration results of A were relatively high, while the calibration results of B were relatively low. In terms of energy response, the calibration results showed a similar pattern to angle response. In terms of linear response, the calibration results of both A and B were satisfactory. Conclusion Both A and B can be used for normal calibration of H_p(3) in a standard X-ray RQR radiation field. However, in actual monitoring, attention should be paid to the energy and angle response values of TLDs.

Objective:To investigate the influencing factors of refractory anastomotic stenosis after laparoscopic intersphincteric resection (Ls-ISR) for rectal cancer and construction of nomogram prediction model.Methods:The retrospective case-control study was conducted. The clinicopatho-logical data of 495 patients who underwent Ls-ISR for rectal cancer in two medical centers, including 448 patients in Peking University First Hospital and 47 patients in Cancer Hospital Chinese Academy of Medical Sciences, from June 2012 to December 2021 were collected. There were 311 males and 184 females, aged 61 (range, 20-84)years. Observation indicators: (1) incidence of anastomotic stenosis; (2) influencing factors of refractory anastomotic stenosis after Ls-ISR; (3) construction and evaluation of nomogram prediction model for refractory anastomotic stenosis after Ls-ISR. Follow-up was conducted using outpatient examination and telephone interview to detect the incidence of postoperative anastomotic leakage and anastomotic stenosis up to August 2022. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the t test. Measurement data with skewed distribution were represented as M(range). Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test. Univariate and multivariate analyses were conducted using the Logistic regression model. Factors with P<0.10 in univariate analysis were included in multivariate analysis. The R software (3.6.3 version) was used to construct nomogram prediction model. The receiver operating characteristic (ROC) curve was drawn and the area under curve (AUC) was used to evaluate the efficacy of nomogram prediction model. Results:(1) Incidence of anastomotic stenosis. All 495 patients underwent Ls-ISR successfully, without conversion to laparotomy, and all patients were followed up for 47(range, 8-116)months. During the follow-up period, there were 458 patients without anas-tomotic stenosis, and 37 patients with anastomotic stenosis. Of the 37 patients, there were 15 cases with grade A anastomotic stenosis, 3 cases with grade B anastomotic stenosis and 19 cases with grade C anastomotic stenosis, including 22 cases being identified as the refractory anastomotic stenosis. Fifteen patients with grade A anastomotic stenosis were relieved after anal dilation treat-ment. Three patients with grade B anastomotic stenosis were improved after balloon dilation and endoscopic treatment. Nineteen patients with grade C anastomotic stenosis underwent permanent stoma. During the follow-up period, there were 42 cases with anastomotic leakage including 17 cases combined with refractory anastomotic stenosis, and 453 cases without anastomotic leakage including 5 cases with refractory anastomotic stenosis. There was a significant difference in the refractory anastomotic stenosis between patients with and without anastomotic leakage ( χ2=131.181, P<0.05). (2) Influencing factors of refractory anastomotic stenosis after Ls-ISR. Results of multivariate analysis showed that neoadjuvant therapy, distance from tumor to anal margin ≤4 cm, clinic N+ stage were independent risk factors of refractory anastomotic stenosis after Ls-ISR ( hazard ratio=7.297, 3.898, 2.672, 95% confidence interval as 2.870-18.550, 1.050-14.465, 1.064-6.712, P<0.05). (3) Construction and evaluation of nomogram prediction model for refractory anastomotic stenosis after Ls-ISR. Based on the results of multivariate analysis, neoadjuvant therapy, distance from tumor to anal margin and clinic N staging were included to constructed the nomogram prediction model for refractory anastomotic stenosis after Ls-ISR. Results of ROC curve showed the AUC of nomogram prediction model for refractory anastomotic stenosis after Ls-ISR was 0.739 (95% confidence interval as 0.646-0.833). Conclusions:Neoadjuvant therapy, distance from tumor to anal margin ≤4 cm, clinic N+ stage are independent risk factors of refractory anastomotic stenosis after Ls-ISR. Nomogram prediction model based on these factors can predict the incidence of refractory anastomotic stenosis after Ls-ISR.

Objective:To investigate the efficacy of 3D-printed segmental tumor prosthesis for reconstruction of bone defects after resection of weight-bearing long bone tumors in the lower extremity.Methods:A total of 71 patients who received 3D-printed segmental metal tumor prosthesis for reconstruction of bone defects from August 2015 to August 2021 at the Musculoskeletal Tumor Center of Peking University People's Hospital were retrospectively analyzed. There were 40 males and 31 females, aged 23.08±18.52 years (range, 10-63 years). Tumor types: 49 cases of osteosarcoma, 9 cases of Ewing sarcoma, 3 cases of chondrosarcoma, 3 cases of synovial sarcoma, 2 cases of pleomorphic undifferentiated sarcoma, 2 cases of rhabdomyosarcoma, 2 cases of bone metastasis, and 1 case of low-grade malignant tumor of mesenchymal origin. Ennecking stage of bone tumor: 19 cases of stage III, 52 cases of stage IIb. Tumor location: femur 43 cases, tibia 28 cases. Operative time, intraoperative bleeding, patient survival and postoperative complications were recorded. Kaplan-Meier curves for prosthetic survival were plotted. The osseointegration at the prothesis-bone interface was determined by combination of clinical presentation and imaging. Limb function scores were evaluated using the Musculoskeletal Tumor Society (MSTS) 93 function score.Results:All 71 patients successfully completed the operation and were followed up for 24.4±13.2 months (range, 6.6-65.4 months). At the last follow-up, 50 patients survived without disease, 12 survived with the disease, and the remaining 9 cases died with disease. A total of 11 cases showed prosthesis failure, including 1 case of aseptic loosening, 3 cases of screw breakage or periprosthetic fracture, 1 case of periprosthetic infection, and 6 cases of tumor progression involving the prosthesis. The Kaplan-Meier curve showed that the 1-year, 3-year and 5-year survival rates of prosthesis were 94.2%±2.8%, 86.1%±4.7% and 79.5%±9.2%, respectively. 62 patients received functional follow-up, and the MSTS93 functional score at the last follow-up was 23.95±5.03 points (range, 10-30 points), with an excellent rate of 90% (56/62). The score of femoral prosthesis was 24.63±4.97 points (range, 13-30 points) and the score of tibial prosthesis was 23.29±5.09 points (range, 10-29).Conclusion:3D-printed segmental tumor prosthesis for reconstruction of bone defect after resection of weight-bearing long bone tumors in the lower extremity has a relative high survival rate, a low incidence of prosthetic complications, and a good recovery of function, and it can be used as an option for the postoperative reconstruction of bone tumors in weight-bearing bones of the lower extremity.

Objective:To evaluate the clinical outcome of a special physeal sparing knee prosthesis for pediatric distal femoral osteosarcoma regarding the functional outcome, retention of the growth potential of the proximal tibia, and postoperative complications.Methods:A retrospective study was conducted to review 37 pediatric patients with osteosarcoma of distal femur who were treated in a single musculuskeletal tumor center between August 2015 and January 2019. Among them, 21 were boys and 16 were girls, aged from 5 to 12 years at the time of operation, with an average age of 9.1±2.1 years and the height of 115 to 160 cm, with an average of 140±10 cm. Tumor resection of distal femur was performed and the bone defect was reconstructed by a special hinged knee prosthesis which can preserve the proximal tibial epiphyseal plate. Demographic data was recorded. Overall leg length and tibial length was assessed by full-length standing anteroposterior radiographs of bilateral lower extremity with the patella pointing anteriorly preoperativelly and postoperativelly at each follow up. And the growth potential of the affected proximal tibia was calculated by comparing with the preoperative length of tibia. Meanwhile, the functional outcome was assessed by using the Musculoskeletal Tumor Society (MSTS) system, and the postoperative complications were analysed.Results:All patients underwent the tumor resection and reconstruction operation successfully. The average operation duration was 143±41 minutes, ranging 90 to 250 minutes. The average intraoperative blood loss was 314±397 ml, ranging 30 to 2 200 ml. The patients were followed up for 24 to 64 months, averaging 42.3±12.1 months. The postoperative knee range of motion was 100-130 degrees, with an average of 115.6±7.2 degrees. The postoperative MSTS score was 23-30, with an average of 26.7±1.6. To the last follow-up, the limb length discrepancy of the lower limb was 1.3 to 10 cm, and the length of the tibia was shortened from 0 to 3.8 cm compared with the opposite side, with an average of 1.3±1.0 cm. The growth percentage of the proximal tibial epiphysis on the affected side was 30% to 100%, with an average of 70%±17%. Totally, 13 patients suffered postoperative complication, the overall incidence of complications was 35% (13/37), and prosthesis-related complications were 16% (6/37). Three patients with wound dehiscence were managed by debridement and antibiotics. Radiographs revealed femoral stem loosening in a single patient 3 years after the initial operation and then the prosthesis was converted to an adult tumor knee endoprosthesis. Two cases experienced breakage of the femoral stem at 30 and 33 months, respectively, due to an accidental injury. They received revision surgery, and a new femoral prosthesis component was replaced. One patient developed femoral stem breakage at 10 months after surgery due to fatigue fracture, which treated with revision surgery. Tumor recurrence occurred in 6 patients. Among them, tumor recurrence in soft tissue occurred in 4 patients, and treated with regional resection without further recurrence. The other 2 patients experienced tumor recurrence at the distal femoral site, and treated with resection and prosthetic revision.Conclusion:The physeal sparing pediatric knee prosthesis can preserve the growth potential of the proximal tibial epiphyseal plate with good postoperative function and low incidence of prosthesis complications. Therefore, it can be an alternativeespecially for skeletally immature patients with distal femur osteosarcoma.

OBJECTIVE： To establish a method for simultaneous determination of contents of β-pinene， linalool， L-camphor， L-borneol， β-caryophyllene and xanthoxylin in the oil of Blumea balsamifera. METHODS： GC method was adopted. The determination was performed on RTX-1701 capillary column （programmed temperature）. The FID detector was controlled at 240 ℃. The inlet temperature was set at 240 ℃. The carrier gas was high-purity nitrogen 3 mL/min. The the sample size was 0.5 μL， and split ratio was 50 ∶ 1. RESULTS： The linear range of β-pinene， linalool， L-camphor， L-borneol， β-caryophyllene and xanthoxylin were 0.029 7-0.267 1 mg/mL （r＝0.999 9）， 0.024 3-0.218 9 mg/mL （r＝0.999 9）， 0.126 0-1.134 0 mg/mL （r＝0.999 9）， 0.217 2-1.954 8 mg/mL （r＝0.999 9）， 0.136 3-1.226 9 mg/mL （r＝0.999 9）， 0.044 5-0.400 3 mg/mL（r＝0.999 5）， respectively. The limits of quantitation were 0.028 5， 0.008 7， 0.018 6， 0.016 8， 0.014 5， 0.042 1 mg/mL； the limits of detection were 0.009 4， 0.002 9， 0.006 1， 0.005 5， 0.004 8， 0.013 9 mg/mL， respectively. RSDs of precision， stability， reproducibility and durability tests were all lower than 3％. The average recoveries were 98.13％-101.30％（RSD＝1.20％，n＝9），98.44％-101.81％（RSD＝1.28％，n＝9），98.26％-101.05％（RSD＝1.19％，n＝9），99.08％-101.58％（RSD＝0.89％，n＝9），98.66％-101.66％（RSD＝1.17％，n＝9），98.84％-103.60％（RSD＝0.96％，n＝9）， respectively. The contents of 6 components in the sample were 14.552-46.766， 16.951-22.096， 80.597-113.115， 205.224-242.537， 47.761-135.697， 26.493-45.771 mg/g， respectively. CONCLUSIONS： The established method is simple， accurate， precise and reproducible， which can be used for simultaneous determination of contents of 6 components in the oil of B. balsamifera. It can provide reference for comprehensive evaluation and extraction technology study of the oil of B. balsamifera.

Objective:To investigate the effect of thermal conductivity on the apical sealing ability of different dental gutta-percha cones during the warm vertical condensation obturation.Methods:Four kinds of dental gutta-percha cones were used in this study:Bio-GP points (BP,B&L,Korea),large-tapered gutta-percha (DP,DENTSPLY,America),PROTAPER Universal gutta-percha points (DPP,DENTSPLY,America) and mtwo gutta-percha points (VP,VDW,Germany).Volume differences method was used to determine the main components and the thermal conductivity determinator was used to measure the thermal conductivity of these dental gutta-percha cones.Furthermore,20 cones randomly selected from each kind of dental gutta-percha cones.And 10 cones of each dental gutta-percha cones,which were cut out the part of 4 mm in length from the apical end,were heated (200 ℃) from the upper end without compression,and the temperature of the gutta perchacones surface was monitored in time by the infrared thermal imager during the whole heating process.In addition,the rest of the 10 cones of each dental gutta-percha cones were used to obturate the root canal in the transparent root canal resin model using warm vertical condensation technique.The cross-sectional surface was observed by stereomicroscope (× 40) at 1 mm and 3 mm from the working length and the gutta-percha obturation area proportion was measured and analyzed.The data were analyzed by one-way ANOVA.Results:The proportion of inorganic fillers (80.90％ ± 1.14 ％) (P ＜ 0.05) and the thermal conductivity (2.247 ± 0.002)of DP was siguificantly higher than BP (79.28％ ± 3.88％,1.179 ± 0.003),DPP (68.46％ 5.09％,0.604 ±0.001),VP (78.86％ ± 1.87％,1.150 ±0.001) (P ＜0.05).During the thermal obturation without compression at the setting temperature (200 ℃),DP could achieve 65 ℃ beyond 1 mm from the heating point,and BP,DPP and VP only reached 65 ℃ within 1 mm.After warm vertical condensation obturation,all the groups showed increased gutta-percha obturation area proportion.At the position of WL-3,DP (96.89％ ±0.03％) showed significantly higher proportion of gutta-percha obturation area than BP (95.47％ ±0.06％),DPP (95.21％ ±0.03％) and VP (95.15％ ±0.03％) (P ＜ 0.05).Conclusion:DP contains more inorganic fillers,possesses higher thermal conductivity,and leads a better apical sealing ability than BP,DPP and VP at the position of WL-3 during warm vertical condensation obturation.

OBJECTIVETo analyze the main death causes among infants in Guangzhou in 2010-2013 and to provide an objective and scientific basis for risk communication of public health emergencies in the future.

METHODSDescriptive epidemiological method was used to analyze the death causes among infants reported in Guangzhou from the National Death Registration Reporting Information System. The death causes among infants were classified by the 10th international classification of diseases (ICD-10). The constitution and rank order of death causes among infants were analyzed according to the underlying causes of deaths.

RESULTSA total of 4 880 cases of infant deaths were reported in Guangzhou from 2010 to 2013 and infant deaths in floating population were 1.8 (3 135/1 745) times of registered population. The deaths of male infants were 1.73 (3 094/1 786) times of female infants. The neonatal group accounted for 52.32% (2 553/4 880) of total infant deaths and early neonatal group accounted for 64.86% (1 656/2 553) of total neonatal deaths. The top five causes of infant deaths followed by perinatal diseases, congenital malformations, respiratory diseases (mainly pneumonia), accidental deaths and communicable diseases. The mortality ratios were respectively 44.12% (2 153 cases) , 24.73% (1 207 cases), 6.86% (335 cases), 3.48% (170 cases), 3.01% (147 cases) , and no vaccine-related death case was reported.

CONCLUSIONThe primary cause of infant deaths in Guangzhou 2010-2013 was perinatal diseases.

Cause of Death ; China ; Communicable Diseases ; Congenital Abnormalities ; Female ; Humans ; Infant ; Infant Death ; Infant Mortality ; Infant, Newborn ; Male ; Perinatal Mortality ; Respiratory Tract Diseases

BACKGROUND:Discectomy and pedicle fixation fusion are golden standard to repair lumbar degenerative disease, but the treatment would induce other complications such as degeneration of adjacent segments or severer pre-existing spinal degeneration. For the problem of lumbar fusion and fixation, lumbar elastic fixation has recently been a hot focus. ＜br> OBJECTIVE:To evaluate the short-term effectiveness of dynamic lumbar pedicle fixation in repair of lumbar spinal stenosis and lumbar disc herniation. ＜br> METHODS:From December 2010 to December 2012, 62 cases of lumbar spinal stenosis and lumbar disc herniation treated with lumbar dynamic system were included. The involved segments included:5 cases at L 3/4 , 20 cases at L 4/5 , 20 cases at L 5 S 1 , 6 cases at double segment L 3/4 and L 4/5, 8 cases at double segment L 4/5 , L 5 S 1 , 3 cases at L 3/4 and L 5 S 1 . There were 34 males and 28 females with an average age of 50.8 years (range 32 to 72 years). According to different fixation systems, they were assigned to three groups:general dynamic lumbar fixation system in 17 cases, K-Rod posterior dynamic stabilization system in 28 cases, and Dynesys system in 17 cases. The fol ow-up time was from 24 to 48 months. Evaluation indexes included visual analogue scale, Oswestry disability index, imaging analysis and excellent and good rate of curative effects. ＜br> RESULTS AND CONCLUSION:Compared with before treatment, visual analogue scale score and Oswestry disability index were significantly improved at 6 months after treatment and final fol ow-up (P＜0.01). No apparent changes were detected in the length of inserted segments and adjacent segments before treatment and during final fol ow-up. There were no significant differences in the excellent and good rate in each group after treatment (P>0.05). These data indicated that the lumbar dynamic system was an effective option for lumbar disc herniation and spinal stenosis. Although there are some differences in the structure of three kinds of flexible fixation, no obvious difference in early therapeutic effects was detected. Long-term effects deserve further investigations.

Objective To investigate the distribution of-6411A/G (rs208679) polymorphism in the 5' region of catalase (CAT) gene among Han population in Chongqing and its correlation with noiseinduced hearing loss (NIHL).Methods A total of 225 healthy volunteers (normal control group) and 237 noise exposure cases (noise exposure group) were collected from the unrelated Han people in Chongqing.The noise exposure group were further divided into non-deaf group (n =170) and deaf group (n =67) according the presence or absence of NIHL.rs208679 polymorphism in the 5' region of CAT gene was identified using the improved multiplex ligation detection reaction (iMLDR) technique.Genotypes,allelic frequencies and clinical deaf incidence were compared among groups.Results Three genotypes (AA,AG,and GG) were detected in the rs208679 locus.Frequencies of A and G alleles in normal control group and noise exposure group were 0.76 and 0.24 respectively.Genotype distribution in normal control group and noise exposure group showed no deviation from the Hardy-Weinberg equilibrium (P ＞0.05).There were no significant differences in gene polymorphism (AA,AG,and GG) and allelic frequencies (A and G) between normal control group and noise exposure group and between deaf group and non-deaf group (P ＞ 0.05).However,significant difference was observed between deaf group and non-deaf group in recessive analysis (GG vs AG + AA,P ＜ 0.05).Conclusion rs208679 is the predisposing gene to NIHL and can be used as the biomarker for NIHL susceptibility.

Through random sampling,a total of 300 residents of Beijing Changping Ming Tombs Town were selected for home-based questionnaires.The smoking rate of interviewed residents was 21.4％ (53/248).The rate in men (42/125,33.6％ ) was bigber than that in women ( 11/123,8.9％ ).The rate in those with higher education was lower than that in those with lower educational level ( x2 =27.12,P ＜ 0.05 ).The population awareness of tobacco hazards was 80.6％ (200/248).Awareness in smokers was lower than the average awareness of ex-smokers and nonsmokers ( x2 =5.07,P ＜ 0.05 ).The higher the education level,the higher the awareness of tobacco health hazards ( x2 ≈ 19.72,P ＜ 0.05 ).There were differences in awareness among different age groups (x2 =13.37,P ＜ 0.05 ).