In this study, the resistance characteristics of the amphibious vehicle in the transitional stage are studied. A deformable track wheel is designed and its effect on the amphibious vehicle's resistance is studied. The numerical calculation method based on the RANS solver and the towing test method is used to analyse the hydrodynamic performance of the amphibious vehicle. Based on the comparison of the vehicle model with no wheel, the influence of wheels on additional resistance at the groove fault is studied. The inclination angles of the front and rear deformation wheels are studied respectively. The influence and principle of the track wheel configuration on drag are analysed and expounded in terms of pressure distribution, water climbing and spray on the wheel grooves, and the hull attitude. Finally, an adjustment strategy of the deformable configuration wheel in the transition stage is proposed.
Plexiform fibromyxoma (PF) is a unique mesenchymal tumor of the stomach. The molecular characteristics of these tumors remain unclear. Here, we report 10 cases of PF with clinicopathological features and molecular features in detail. The patients ranged in age from 26 to 72 years (mean, 49 y) and most commonly presented with abdominal pain and distension, black stool, and anemia. Eight tumors were located at the antrum while two in the fundus of stomach. Histologically, tumor cells exhibited a plexiform growth pattern with multiple nodules in the muscularis propria of stomach wall and infiltrative borders. Immunohistochemically, all tumors were strongly positive for vimentin and smooth muscle actin (SMA), some were staining for CD10 (5/10), desmin (5/10), H-caldesmon (6/10) and progesterone receptor (PR, 6/10), however, CD34, S-100, Estrogen Receptor (ER), ALK, CD117 and DOG-1 were all negative in our cases. The glioma-associated oncogene homologue 1 (GLI1) gene translocation was detected in eight cases by FISH with three positive and five negative. Mutation analyses of C-KIT and platelet-derived growth factor receptor alpha (PDGFRA) genes were performed on five cases and all of which were wild-type for mutation. Our follow-up indicated that all of the patients made an uneventful recovery at 24 to 95 months after diagnosis. In summary, the distinctively histological features and immunohistochemical positivity of SMA, CD10 and PR can help differentiate PF from other gastrointestinal mesenchymal tumors. GLI1 gene translocation offers an additional molecular instrument for the diagnosis. The expression of PR and the existence of GLI1 gene translocation in PF highlights of our article.
Abstract. In order to reduce the resistance and increase speed for a high-speed wheeled amphibious vehicle, a wheel-retracting mechanism was applied to a walking mechanism and the influence was researched. Firstly, to obtain a reliable numerical method, a realizable shear stress transport (SST) k-ω turbulence model and computational fluid dynamic (CFD) model built by an overset mesh technique was used and compared with the corresponding model tests. Secondly, the effect of the wheels' flip angle on resistance, heave and pitch was investigated. Then, the wheel well was optimized by numerical simulation. Finally, the results showed that the influence of the wheels on resistance was more significant, and the larger the wheels' flip angle was, the more significant the resistance reduction would be. An optimized wheel well was beneficial to resistance reduction. Furthermore, the running attitude became steadier, thereby decreasing the heave and pitch.
Objective
To investigate the role of ATRX and P53 gene mutations in the classification of diffuse glioma in Chinese.
Methods
A total of 89 cases of diffuse astrocytoma (IDH mutation) or diffuse astrocytoma (IDH wild type) and all levels of oligodendroglioma from 2016 to 2017 were collected, and detected the expression of ATRX protein and over expression of P53 protein by immunohistochemistry, and analyzed their expression in different types of diffuse gliomas.
Results
The ratio of ATRX loss expression in diffuse astrocytoma (IDH mutation) (17/24) was higher than that in oligodendrogliomas (3/16), P<0.01; the ratio of P53 over expression in diffuse astrocytoma (IDH mutation) (15/24) was higher than that in oligodendrogliomas (1/16), P<0.01; the ratio of ATRX loss expression in diffuse astrocytoma (IDH mutation) (71%, 17/24) was higher than that in diffuse astrocytoma (IDH wild) (41%, 20/49), P<0.05.
Conclusions
ATRX and P53 mutation is one of the molecular genetic characteristics of diffuse astrocytoma (IDH mutation), which may be contributed to diagnose diffuse astrocytoma.
Key words:
Diffuse glioma; Tumor suppressor protein P53; Alpha thalassemia/mental retardation syndrome-X
Glioblastoma (GBM) is one of the most deadly primary malignant brain tumors in adults. R132H mutation of isocitrate dehydrogenase 1 (IDH1) predicts a better prognosis of GBM. IDH1-R132H is associated with increased hypoxia-inducible factor-1α (HIF-1α) expression in GBM tumors. However, the molecular mechanism underlying IDH1-R132H-HIF-1α signaling in GBM is still unclear.We aimed to investigate the molecular pathway of IDH1-R132H-HIF-1α in the regulation of GBM.U87 and U251 GBM cells and xenograft tumor mice were used.We found that overexpression of IDH1-R132H decreased cell proliferation, increased apoptosis, decreased migration and invasion, enhanced temozolomide (TMZ)-induced cytotoxicity, and reduced tumor growth in xenograft mice. Overexpression of IDH1-R132H increased the expression of HIF-1α and downregulation of HIF-1α suppressed IDH1-R132H-induced effect on GBM. Reactive oxygen species (ROS) level was increased by IDH1-R132H over expression and the use of antioxidant inhibited IDH1-R132H-induced increase of HIF-1α expression. FAT Atypical Cadherin 1 (FAT1) expression was increased by IDH1-R132H over expression. Knockdown of FAT1 blocked IDH1-R132H-induced reduction of tumor growth in xenograft mice. Down regulation of FAT1 decreased HIF-1α expression and inhibited IDH1-R132H-induced increase of ROS level.Our findings provide new insights into IDH1-R132H-regulated downstream signaling in GBM and highlight the importance of IDH1-R132H-FAT1-ROS-HIF-1α signaling pathway in potential therapeutic intervention of GBM.
The median and/or paired fin (MPF) swimming mode of fish has extremely strong maneuverability, which is urgently needed for unmanned underwater vehicles. Therefore, determining the mechanism of greater maneuverability of fish in the MPF swimming mode is particularly important. To fill the research gap in the entire turn maneuvering process in MPF swimming mode under self-propulsion, a numerical solution method for three degree-of-freedoms self-propelled swimming of biomimetic robotic fish (BRF) coupled with fluid dynamics and body dynamics were established. Our results revealed that the turning radius of the BRF increases with the increase in the pectoral fin rotation amplitude in both drag-based and lift-based modes. Interestingly, owing to the special streamlined shape of the fish body, it can passively generate thrust during turn maneuvering. According to vortex dynamics, the trailing-edge vortex (TEV) and tip vortex (TV) generated in the power stroke form a vortex ring together with the TEV generated in the recovery stroke during one cycle in drag-based mode. The TEV and TV generated in every half cycle in lift-based mode form a vortex ring, resulting in two vortex rings in one cycle. The vortex ring generation mechanism is the mechanism by which the pectoral fins cannot generate continuous thrust in drag-based mode but can generate continuous thrust in the lift-based mode. The results reveal the BRF labriform mode turning characteristics as well as the relation mechanism between vortex dynamics and thrust, which lays a theoretical foundation for highly maneuverable BRF development.
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