Objective To explore the CTV to PTV external expansion boundary and the effect of the dose of normal lung tissue under different fixed modes by a comparative analysis of combined body position and thermoplastic film fixed set-up error of radiation therapy for lung cancer. Methods From October 2016 to March 2018, the patients who received chest radiology at the Tangshan people's hospital were enrolled as subjects retrospectively divided into two groups, including 50 patients with lung cancer radiotherapy with combined body position fixation, and 40 patients with lung cancer with thermoplastic film fixation. The two groups of patients drew the target areas in accordance with the unified standard, and the set-up error of left and right, up and down, front and rear ( x, y, z axis) were recorded respectively after 1 time/week cone CT( CBCT) matched with the planned CT image and analyzed by t test. According to the MPTV =2. 5Σ+0. 7δ, CTV to PTV external expansion boundary in the combined body position group were calculated. And the V5、V20 and V30 of two groups of patients were calculated and analyzed by TPS system. Results The set-up error of the combined body position group and thermoplastic film group were respectively (1. 00 ± 0. 58) mm and (3. 28 ± 0. 43) mm on the x axis, (1. 42 ± 0. 28) mm on the y axis and (4. 03 ± 0. 41) mm, (1. 06 ± 0. 44) mm and (3. 18 ± 0. 34) mm on the z axis. The set-up errors of the two groups were statistically significant on x, y and z axis( t= -20. 740, -35. 596, -25. 015,P<0. 05). There was no significant difference in set-up errors between the central and peripheral lung cancer patients and between left and right lung cancer patients(P>0. 05). Through the MPTV =2. 5Σ+0. 7δ, CTV to PTV external expansion boundary in the combined body position fixation group was 2. 906 , 3. 746 and 2. 958 mm on x, y and z axis respectively. The comparison between group A and B showed that the mean values of V5 , V20 and V30 in group B were reduced by 1. 5％, 3. 1％ and 4. 8％ respectively compared with group A. Conclusions The combined body position technique can improve the accuracy of lung cancer patients after radiation therapy,and further reduce the boundary of CTV to PTV, which is of certain value to reduce the occurrence of radiation pneumonitis.

The peroxisome proliferator-activated receptor gamma(peroxisome proliferator-activated receptor gamma,coactivator 1 beta,PPARGC1B)gene is an intranuclear receptor transcription fac-tor responsible for regulating the expression of target genes.To comprehend the characteristics and mutations of the PPARGC1B gene within the Sichuan yak population,the SNP loci of the PPARGC1B gene were identified through direct sequencing of PCR products.Additionally,the cod-ing region of the PPARGC1B gene was obtained via PCR amplification and sequencing.Bioinforma-tics analyses were conducted to predict protein-coding and mRNA secondary structure.This study identified four exon SNP mutation sites(E9-189A→C,E9-387G→A,E9-542C→T,and E9-554T→C)based on the single nucleotide polymorphism analysis of the PPARGC1B gene in Sichuan yaks.Notably,the E9-387G→A and E9-554T→C loci exhibited significant correlations with shear force and backfat thickness in Sichuan yaks.Subsequently,bioinformatics analysis of the four mutation sites revealed that the PPARGC1B protein is an acidic,unstable,non-transmembrane,and non-secretory hydrophilic protein with a coiled helix structure.It lacks a signal peptide and transmembrane region,predominantly functions in the nucleus,and features 106 phosphorylation sites,one glycosylation site,and one conserved RRM structure.The secondary structure comprises mainly α-helix and random coils.Although the protein structure of the PPARGC1B gene remained unchanged post-mutation,there were significant differences in mRNA secondary structure.These findings suggest that the polymorphic loci of the PPARGC1B gene in Sichuan yaks could serve as a theoretical basis for enhancing meat quality traits through molecular biological methods,presen-ting practical applications in breeding.

Objective    To analyze the outcomes of complicated congenital heart diseases (CCHD) patients accepting multiple (>2) re-sternotomy operations. Methods    We retrospectively analyzed the clinical data of 146 patients undergoing multiple cardiac re-sternotomy operations between 2015 and 2019 in our center. There were 95 males and 51 females with an age of 4.3 (3.1-6.8) years and a weight of 15.3 (13.4-19.0) kg at last operation. Results    The top three cardiac malformations were pulmonary atresia (n=51, 34.9%), double outflow of right ventricle (n=36, 24.7%) and functional single ventricle (n=36, 24.7%). A total of 457 sternotomy procedures were performed, with 129 (88.3%) patients undergoing three times of operations and 17 (11.7%) patients undergoing more than three times. Fifty-two (35.6%) patients received bi-ventricular repair, 63 (43.1%) patients received Fontan-type procedures, and 31 (21.2%) patients underwent palliative procedures. Ten (6.8%) patients experienced major accidents during sternotomy, including 7 (4.8%) patients of urgent femoral artery and venous bypass. Eleven (7.5%) patients died with 10 (6.8%) deaths before discharge. The follow-up time was 20.0 (5.8-40.1) months, and 1 patient died during the follow-up. The number of operations was an independent risk factor for the death after operation. Conclusion    Series operations of Fontan in functional single ventricle, repeated stenosis of pulmonary artery or conduit of right ventricular outflow tract post bi-ventricular repair are the major causes for the reoperation. Multiple operations are a huge challenge for CCHD treatment, which should be avoided.