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In order to meet the requirements of high-precision vehicle positioning in complex scenes, an observation noise adaptive robust GNSS/MIMU tight fusion model based on the gain matrix is proposed considering static zero speed, non-integrity, attitude, and odometer constraint models. In this model, the robust equivalent gain matrix is constructed by the IGG-Ⅲ method to weaken the influence of gross error, and the on-line adaptive update of observation noise matrix is carried out according to the change of actual observation environment, so as to improve the solution performance of filtering system and realize high-precision position, attitude and velocity measurement when GNSS signal is unlocked. A real test on a road over 600km demonstrates that, in about 100km shaded environment, the fixed rate of GNSS ambiguity resolution in the shaded road is 10% higher than that of GNSS only ambiguity resolution. For all the test, the positioning accuracy can reach the centimeter level in an open environment, better than 0.6m in the tree shaded environment, better than 1.5m in the three-dimensional traffic environment, and can still maintain a positioning accuracy of 0.1m within 10s when the satellite is unlocked in the tunnel scene. The proposal and verification of the algorithm model show that low-cost MIMU equipment can still achieve high-precision positioning when there are scene feature constraints, which can meet the problem of high-precision vehicle navigation and location in the urban complex environment.

The paper highlights the importance of optimal design model in the design evaluation of complex sealing mechanism. Sealing mechanism of the high-speed assembly machine is taken as the research object and construct rigid-flexible coupling dynamic equation. Dynamic characteristics of the sealing mechanism are analyzed by MATLAB. The maximum dynamic stress and reducing the acceleration of the end F are regarded as the optimization object. Cam profile curve parameter and the link cross section parameter are designed as the variables to construct the optimization design model of the whole sealing mechanism, and nonlinear constraint problem is transformed into a linear constraint problem. Based on the MATLAB genetic algorithm toolbox, the optimal design model of the sealing mechanism is solved, and the optimal result is obtained. [ABSTRACT FROM AUTHOR]

Citrate is one of the most important metabolites determining the flavour of citrus fruit. It has been reported that nitrogen supply may have an impact on acid level of fruit. Here, the relationship between nitrogen metabolism and citrate catabolism was studied in pumelo juice sacs. Differences in metabolites, gene expression and flux distributions were analyzed in juice sacs incubated in medium with and without NH 4 + . Compared with those incubated with NH 4 + , juice sacs under nitrogen deficiency exhibited enhanced flux through phosphoenolpyruvate carboxykinase (PEPCK) and accelerated consumption of citrate, while the other two TCA cycle efflux points, through malic enzyme (ME) and glutamate dehydrogenase (GDH), were both repressed. Consistent with the estimated fluxes, the expression of PEPCK1 was upregulated under nitrogen deficiency, while that of GDH1, GDH2, NAD-ME1 and NADP-ME2 were all repressed. Thus, we propose that PEPCK1 contributes to citrate degradation under nitrogen limitation., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Objective: To assess the value of detecting peripheral blood circulating tumor cells (CTCs) in the diagnosis and treatment of hepatocellular carcinoma (HCC)., Methods: A total of 296 patients diagnosed with HCC admitted in our department from July 2013 to January 2015 were analyzed, with 39 patients with benign liver disease serving as the control group. The distribution of CTCs in the peripheral blood of HCC patients were detected by CanPatrol(TM) CTCs, and its relationship with the clinical features and prognosis of the patients were analyzed., Results: s CTCs were detected in 64.5% (191/296) of the HCC patients but in none of the control group (P<0.05). Positive CTCs in peripheral blood of HCC patients were significantly correlated with serum AFP level, tumor number, TNM stage, BCLC stage, portal vein tumor thrombus and metastasis (P<0.05). In 127 HCC patients receiving radical surgery, the patients positive for CTCs showed significantly shorter relapse-free survival time (P<0.05)., Conclusion: Positive CTCs in the peripheral blood may indicate a poor prognosis in HCC patients. CTCs may serve as a indicator for monitoring the prognosis of HCC.

Objectives: To evaluate the characteristic morphology of heel spur, and to investigate the relationship of heel spur and plantar heel pain., Methods: From June 2005 to April 2009, 210 cases (254 feet) with heel spur (according to Denis Pain Scale) were divided into cases group 1 (P2, n = 46), 2 (P3, n = 44), 3 (P4, n = 42), 4 (P5, n = 36) and controls group (P1, n = 42). Three-dimensional reconstruction of heel spur was performed in all groups using volume rendering based on multi-slice CT data by Super Image orthopedics edition 1.0. The characteristic morphology of heel spur was observed and the data were measured and analyzed, involving the width of basilar part, the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur., Results: Parts of cases groups displayed coarse arcuate edge and undersurface with one or more little heel spurs adhere to heel spur, of which the numbers were greater than controls group, especially in cases group 4. No significant difference of the width of basilar part of heel spur was found among 5 groups (F = 2.32, P > 0.05). However, obvious difference was found in the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur (F = 8.23, 6.82, 5.87, P < 0.05). Compared with the controls group, the angle between heel spur and planta pedis of cases groups had higher degrees, but the difference of the other data presented irregular., Conclusions: The characteristic morphology of heel spur varies in patients associated with plantar heel pain. No correlation is found between the severity and the morphological data, including the width of basilar part, the length, the angle between heel spur and planta pedis, and the angle between the longitudinal axis of calcaneus and heel spur.