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A study on the load characteristics of the modified gear planetary gear systems is conducted to address the issue of uneven loads between planetary gears due to manufacturing and installation errors, which result in deviations between the radial and circumferential installation positions of planetary gears and non-offset values. Based on the theory of rotor dynamics, the time-varying stiffness and the radial and circumferential offsets of the planetary gears are considered, and the five-degree-of-freedom dynamic model of the planetary gear transmission system with addendum modification is established. The response and frequency spectrum of the system are solved by the Runge-Kutta method. The load distribution characteristics of the planet gears under different radial offsets, circumferential offsets, and comprehensive offsets are analyzed. The influence of the radial and circumferential offset of the planetary gear on the load distribution of the planetary gear transmission system is discussed, and the variation law of the load vibration amplitude of the planetary gear transmission system with addendum modification under the time and frequency is obtained. The simulation results show that the load characteristics of the planetary gear train considering the error are quite different from those in theory. Its vibration amplitude of the planetary gear transmission system is greatly affected by the radial offset, and the large radial offset has the greatest impact on the load of the planetary gear. Small deflections of the planetary gear during installation can lead to large changes in the load characteristics. The planetary gear transmission system load test platform is built, the frequency-doubling vibration response signal of the planetary reducer housing is tested, and the relation between the planetary gear transmission system load force and vibration response is obtained. The amplitude variation trend in the experimental results is similar to that in the simulation analysis, and the correctness of the established model and solution method is verified.

Objective·To analyze the clinicopathologic characteristics, gene mutation profile, and prognostic factors of thyroid diffuse large B-cell lymphoma (DLBCL).Methods·From November 2003 to December 2021, a total of 66 patients with thyroid DLBCL [23 cases (34.8%) with primary thyroid DLBCL, and 43 cases (65.2%) with secondary thyroid DLBCL] admitted to Ruijin Hospital, Shanghai Jiao Tong University School of Medicine were retrospectively analyzed for their clinicopathological data, survival and prognostic factors. Gene mutation profiles were evaluated by targeted sequencing (55 lymphoma-related genes) in 40 patients.Results·Compared to primary thyroid DLBCL, secondary thyroid DLBCL had advanced ratio of Ann Arbor stage Ⅲ‒Ⅳ (P=0.000), elevated serum lactate dehydrogenase (LDH) (P=0.043), number of affected extranodal involvement ≥2 (P=0.000), non-germinal center B cell (non-GCB) (P=0.030), BCL-2/MYC double expression (DE) (P=0.026), and international prognostic index (IPI) 3‒5 -scores (P=0.000). The proportion of patients who underwent thyroid surgery (P=0.012) was lower than that of patients with primary thyroid DLBCL. The complete remission (CR) rate in primary thyroid DLBCL patients was higher than that in secondary thyroid DLBCL patients (P=0.039). Fifty-five patients (83%) received rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP)-based first-line regimen. The estimated 5-year progression free survival (PFS) rate of primary thyroid DLBCL patients was 95.0%, higher than the 49.7% of the secondary patients (P=0.010). Univariate analysis showed that Ann Arbor Ⅲ‒Ⅳ (HR=4.411, 95%CI 1.373‒14.170), elevated LDH (HR=5.500, 95%CI 1.519‒19.911), non-GCB (HR=5.291, 95%CI 1.667‒16.788), and DE (HR=6.178, 95%CI 1.813‒21.058) were adverse prognostic factors of PFS in patients with thyroid DLBCL. Ann Arbor Ⅲ‒Ⅳ (HR=7.088, 95%CI 0.827‒60.717), elevated LDH (HR=6.982, 95%CI 0.809‒60.266), and DE (HR=18.079, 95%CI 1.837‒177.923) were adverse prognostic factors of overall survival (OS). Multivariate analysis showed that Ann Arbor Ⅲ‒Ⅳ (HR=4.693, 95%CI 1.218‒18.081) and elevated LDH (HR=5.058, 95%CI 1.166‒21.941) were independent adverse prognostic factors of PFS in patients with thyroid DLBCL. Targeted sequencing data showed mutation frequency >20% in TET2 (n=14, 35%), KMT2D (n=13, 32%), TP53 (n=11, 28%), GNA13 (n=10, 25%), KMT2C (n=9, 22%), and TP53 were adverse prognostic factors of PFS in patients with thyroid DLBCL (P=0.000).Conclusion·Patients with primary thyroid DLBCL have better PFS and OS than those with secondary thyroid DLBCL. Ann Arbor Ⅲ‒Ⅳ, elevated LDH, non-GCB, and DE (MYC and BCL2) are adverse prognostic factors in thyroid DLBCL. TET2, KMT2D, TP53, GNA13, and KMT2C are commonly highly mutated genes in thyroid DLBCL, and the prognosis of patients with TP53 mutations is poor.