Objective To investigate the normal position and configuration of anterior mediastinum.Methods Chest CT scanning was performed in 100 healthy volunteers. Various parameters of the anterior mediastinum were measured, including position (shift distance from medial line of the body),frontal and retral width, and anterioposterior dimension.Results The normal range (with the limit of 95%) of the anterior mediastinum included: the position was shifted 5 mm to right and 15 mm to left, the frontal width was under 30 mm in both man and woman, the posterior width was under 40 mm in woman, and under 50 mm in man, the anterioposterior diameter was under 30 mm in woman and under 35 mm in man.Conclusion The normal region about position and configuration of the anterior mediastinum is established in this study. These data will helpful in detecting the subtle mediastinal shift or other abnormal situation affected the mediastinum.

Objective To evaluate the effects of the project of ditching for drain on Oncomelania hupensis snail control and flood prevention security and explore the optimal engineering design plan in Dongting Lake region. Methods A retrospective study was performed on the previous studies about the project of ditching for drain. The reference values of project indices were determined. The outside levee of Nanhu New Distinct of Yueyang City in Dongting Lake region was selected as the study area , and the cross section of marshland perpendicular to the center line of the levee was extracted to research. According to the situa?tions of various water levels,a dynamic simulation was performed on the effect and security of the project of ditching for drain through the software FLAC3D. Results The retrospective study showed that the project would be effective when the relatively subsoil water level decreased by 0.35 m,and the soil water content decreased correspondingly. The dynamic simulation by FLAC3D showed that the minimum safe distances between transverse ditch 1,vertical ditch and levee toe should be 25 m and 13 m respectively. The digging depth of transverse ditch and vertical ditch should be 1.2 m and 1.0 m respectively. If the width of marshland in drought period was less than 500 m,one transverse ditch was efficient. Otherwise,more transverse ditches should be set with the intervals of 300 m. Conclusions The project of ditching for drain is an effective ecological snail elimination method. Optimizing the digging depth of ditches and distances between transverse ditches,vertical ditch and levee toe will en?sure the effects and security of the project.

Objective To compare the efficacy and toxicities between preoperative concomitant boost intensity-modulated radiotherapy (IMRT) and 3-dimensional conformal RT (3-DCRT) for locally advanced rectal cancer.Methods A prospective study from May 2010 to May 2015.A total of 130 patients with histologically confirmed,newly diagnosed,locally advanced rectal adenocarcinoma (cT3-T4 and/or cN +) located within 10 cm from the anal verge were included in this study.The patients were divided into IMRT and 3D-CRT groups by random number table method.Sixty-six patients were treated with IMRT,and the other sixty-four patients were treated with 3-DCRT.In the IMRT group,the prescription dose was 1.8 Gy/fraction to 45 Gy to the pelvis and 2.2 Gy/fraction to 55 Gy to the gross tumor volume simultaneously.The 3D-CRT prescription was 45 Gy in 25 fractions to the pelvis.Capecitabine (1 650 mg· m 2 · d-1) was given twice daily from days 1 to 14 and days 22 to 35 during RT in both arms.Total mesorectal excision (TME) was scheduled 6-8 weeks after the completion of chemoradiation.Results There were no significant differences in age,gender,tumor location,pathological differentiation degree and clinical stage between the two groups.Two patients withdrew from the study:one for grade 3 radiation dermatitis in IMRT group and the other for grade 3 fatigue in 3D-CRT.There was no significant difference in hematologic or nonhematologic toxicities between the two groups.No grade 4 or 5 toxicity was observed in either group.Compared with conformal radiotherapy,IMRT did not increase the difficulty of surgery.No significant difference was found in type of surgery or postoperative complications between the two groups.The rate of tumor regression grade (TRG) 4 (pathologic complete response,pCR) was 22.7％ for IMRT and 15.6％ for 3D-CRT,respectively(P ＞ 0.05).The rate of both TRG4 and 3 was 42.4％ for IMRT and 25.0％ for 3D-CRT,respectively (x2 =4.406,P=0.036).Conclusions Neoadjuvant concomitant boost IMRT is feasible and has a higher histopathological regression for patients with locally advanced rectal cancer.Trial registration Chinese clinical trial registry,ChiCTR-IN R-16008004.

Objective To study the morphological change of Schistosoma japonicum eggs processed by calcium cyanamide synthetic drug,so as to provide the basis for further study of the mechanism that calcium cyanamide synthetic drug to schisto?some eggs. Methods The calcium cyanamide synthetic drug was added to the cattle feces containing schistosome eggs and mixed up,and then the cattle feces was stacked as original shape on the marshland. Blank controls were set at the same time. The cattle feces samples were collected and the schistosome eggs were observed under a microscope on the 1st,2nd,3rd,7th day after the experiment. Results By the effect of calcium cyanamide synthetic drug,the color of eggs was deepening gradual?ly,the miracidia were atrophied,and the shells of eggs were thickened. The embryonic membrane of miracidia was no longer completed 3 days later,and the miracidia were deformed severely 7 days later. The atrophy of miracidia was not obvious in the blank controls. Conclusion The schistosome miracidia and embryonic membrane can be damaged by the calcium cyanamide synthetic drug,and worse damaged with time extending.

Objective To explore the dosimetric differences between abdominal deep inspiration breath hold(ADIBH)mode and free breath(FB)mode in intensity modulated radiation therapy(IMRT)for left breast cancer.Methods From July 2022 to May 2023,a total of 22 patients who needed adjuvant radiation therapy after left breast cancer surgery in the hospital were selected as the research objects.The simulated computed tomography(CT)positioning images of ADIBH and FB modes were collected,the planned target volume(PTV)and endangered organs were outlined,the IMRT plan was designed,and the dosimetric param-eters of the two modes were compared.Results There was no significant difference in the mean dose(Dmean),homogeneity index(HI)and conformity index(CI)of PTV between the ADIBH and the FB modes(P＞0.05).Compared with the FB mode,the heart Dmean,V5,V10,V20,V30 and V40 in the ADIBH mode decreased by 2.95 Gy,12.21％,8.26％,6.56％,5.41％and 3.48％,respectively,and the left anterior descending(LAD)coronary artery Dmean,maximum dose(Dmax),minimum dose(Dmin)and V40 decreased by 15.99 Gy,16.10 Gy,0.82 Gy and 13.73％,respectively,with statistical significance(P＜0.05).Compared with the FB mode,the dose and volume of heart irradiation in the ADIBH mode at the same level were significantly reduced.Pearson correlation analysis showed that there was a positive correlation between heart Dmean and LAD Dmean in the ADIBH mode(r=0.72),and between heart Dmean and LAD Dmean in the FB mode(r=0.69).Compared with the FB mode,the left lung Dmean of the ADIBH mode decreased by 0.99 Gy,and the difference was statistically significant(P＜0.05).However,there was no significant difference in left lung V5,right lung Dmean and right breast Dmean between the two breathing modes(P＞0.05).Conclusion ADIBH mode can effectively reduce the dose to the heart and LAD,and play a good protective role.