ABSTRACT To solve the problems of low efficiency, poor fertilizer application, and low fertilizer utilization rate of existing wheat layered fertilization devices (LFD). This paper proposed a layered fertilization mode combining shallow fertilizer application based on rotary tillage and middle/deep fertilizer application of layered fertilizer shovel (LFS), and designed a combined spatial layered fertilization device with a fixed proportion. A discrete element simulation model consisting of soil, LFS and fertilizer was established. Taking the variation coefficients of fertilization amount as the evaluation indicator and changing the sidewall deflection angle, rear inclination angle, upper channel length of LFS, a three-factor three-level quadratic rotational orthogonal experiment was carried out. The optimal parameter combination was obtained: the deflection angle was 9.5°, the inclination angle was 57°, and the channel length was 280 mm. The corresponding variation coefficients of fertilizer application depth were 4.55%, 8.44%, and 6.93% while working stably under the optimal combination, which is consistent with the simulation results. The results showed that LFD can apply fertilizer underground in three layers: 0~10, 15, and 20 cm, with the proportion of shallow, middle, and deep fertilizers being 30%, 35%, and 35%, which can meet the agronomic requirements for winter wheat growth.

Abstract In this study, drying fractionation beef tallow was obtained, and then the beef tallow was analyzed by headspace gas chromatography-ion mobility spectrometry (GC-IMS). The experimental results showed that with the decrease in fractionation temperature, the content of saturated fatty acids displayed a decreasing trend, while the content of unsaturated fatty acids displayed an increasing trend. The results of determination of peroxide value, acid value and iodine value showed that the acid value of the components increased with the decrease of the fractionation temperature. A total number of 63 volatile compounds were detected through (GC-IMS), and qualitative and quantitative analyses were performed in order to determine the contents of volatile compounds in samples. The results also indicated that esters, aldehydes, ketones, and alcohols of macromolecular volatile components mainly appear in the MP30, MP40, and MP40+ components, while the volatile components of MP24 are mainly small molecules of esters, alcohols, aldehydes, and ketones. Indeed, in this study, ion migration chromatography fingerprint library of the characteristic components of beef tallow was also constructed, and the generated (GC-IMS) two-dimensional spectrum was used to analyze the difference characteristics of beef tallow, which provides theoretical guidance for the physical and chemical properties of beef tallow.

Abstract In this study, we investigated the preconsolidation pressure (P C) of sedimentary soft rock and its relationship with brittle-ductile transition (BDT) pressure. We proposed a generalized preconsolidation pressure (P G) suitable for both soil and sedimentary soft rock, which is defined in terms of the yield stress of the initial sediment structure under confined lateral compression. We then explored the digenetic effect on P G using 24 sediment types. Next, P G and BDT pressure were verified using confined compression and conventional triaxial tests, respectively, on red-bed soft rock in the Dingxi region of China. Finally, we discussed the BDT mechanism and analyzed the relationship between the two characteristic pressures for a given initial yield surface considered structural strength. We found that the relationship was dependent on the strength parameters, the initial structural strength, and the coefficient of earth pressure at rest. The findings of this study will have a significant impact on the determination of BDT pressure of sedimentary rock in future studies.

OBJECTIVES: This study explored the relationship between skipping breakfast and physical fitness in a group of school-aged adolescents in China. METHODS: This cross-sectional study from the Chinese National Surveillance on Students’ Constitution and Health (CNSSCH) survey in Ningbo, China, used a standardized questionnaire to assess the frequency of breakfast consumption. Physical fitness was measured through standing long jump, 50-m sprint, 1,000 (or 800)-m run, and vital capacity tests. Multiple linear regression analysis was used to investigate the relationship between the frequency of breakfast consumption and physical fitness. RESULTS: Our study included a total of 1,849 school-aged adolescents (aged 15.53±1.80 years). Among boys, non-breakfast-skippers had good scores for 50-m sprints, 1,000-m run, and vital capacity tests when compared with breakfast skippers (all p<0.05). Among girls, non-breakfast-skippers had a good scores for the standing long jump test compared with breakfast skippers (p=0.003). The multiple linear regression model showed that not skipping breakfast was positively associated with vital capacity (β=-173.78, p=0.004) and inversely associated with 50-m sprint (β=-0.12, p=0.018) and 1,000-m run times (β=-8.08, p=0.001) in boys. CONCLUSION: The results of this cross-sectional study revealed that skipping breakfast might be associated with lower physical fitness in Chinese adolescents aged 13-18 years, especially boys. Breakfast consumption should be promoted among Chinese school-aged boys.

OBJECTIVE: To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories. MATERIALS AND METHODS: A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories. RESULTS: The gross tumor volume could predict regional lymph node metastasis (p<0.0001) in the univariate analysis, and the multivariate analyses indicated that the gross tumor volume was an independent risk factor for regional lymph node metastasis (p=0.005, odds ratio=1.364). The Mann-Whitney U test showed that the gross tumor volume could distinguish N0 from the N1-N3 categories, N0-N1 from N2-N3, and N0-N2 from N3 (all p<0.0001). In the T1-T4a categories, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 12.3 cm3), N0-N1 from N2-N3 (cutoff, 16.6 cm3), and N0-N2 from N3 (cutoff, 24.6 cm3). In the T4a category, the gross tumor volume could differentiate N0 from the N1-N3 categories (cutoff, 15.8 cm3), N0-N1 from N2-N3 (cutoff, 17.8 cm3), and N0-N2 from N3 (cutoff, 24 cm3). CONCLUSION: The gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict regional lymph node metastasis and N categories.

OBJECTIVE: The aim of this study was to determine whether and how the diameter of the vein that gives rise to the inflowing vein of the esophageal and gastric fundic varices secondary to posthepatitic cirrhosis, as measured with multidetector-row computed tomography, could predict the varices and their patterns. METHODS: A total of 106 patients with posthepatitic cirrhosis underwent multidetector-row computed tomography. Patients with and without esophageal and gastric fundic varices were enrolled in Group 1 and Group 2, respectively. Group 1 was composed of Subgroup A, consisting of patients with varices, and Subgroup B consisted of patients with varices in combination with portal vein-inferior vena cava shunts. The diameters of the originating veins of veins entering the varices were reviewed and statistically analyzed. RESULTS: The originating veins were the portal vein in 8% (6/75) of patients, the splenic vein in 65.3% (49/75) of patients, and both the portal and splenic veins in 26.7% (20/75) of patients. The splenic vein diameter in Group 1 was larger than that in Group 2, whereas no differences in portal vein diameters were found between groups. In Group 1, the splenic vein diameter in Subgroup A was larger than that in Subgroup B. A cut-off splenic vein diameter of 8.5 mm achieved a sensitivity of 83.3% and specificity of 58.1% for predicting the varices. For discrimination of the varices in combination with and without portal vein-inferior vena cava shunts, a cut-off diameter of 9.5 mm achieved a sensitivity of 66.7% and specificity of 60.0%. CONCLUSION: The diameter of the splenic vein can be used to predict esophageal and gastric fundic varices and their patterns.