Numerical modeling of tectonic stress field and fault activity in North China

On the basis of a 3-dimension visco-elastic finite element model of lithosphere in North China, we numerically simulate the recent mutative figures of tectonic stress field. Annual change characteristics of stress field are; 1) Maximum principal tensile stress is about 3–9 kPaa−1 and its azimuth lie in NNW-SSE. 2) Maximum principal compressive stress is about 1–6 kPaa−1 and its azimuth lie in NEE-SWW. 3) Maximum principal tensile stress is higher both in the west region and Liaoning Province. 4) Variation of tectonic stress field benefits fault movement in the west part and northeast part of North China. 5) Annual accumulative rates of Coulomb fracture stress in Tanlu fault belt have segmentation patterns: Jiashan-Guangji segment is the highest (6 kPaa−1), Anshan-Liaodongwan segment is the second (5 kPaa−1), and others are relatively lower (3–4 kPaa−1)

The clinical, radiological, and surgical characteristics of anterior perforated substance glioma: a retrospective study

Abstract Background To explore the clinical, radiological, and surgical characteristics of anterior perforated substance (APS) gliomas. Methods Twenty patients with APS glioma who were treated with surgery between March 2019 and January 2022 from Tiantan hospital were retrospectively reviewed. The clinical, histological and radiological data were collected. Results Twenty patients, including 7 males (55%) and 13 females (45%), with a mean age at diagnosis of 37.9 years (range, 28–53 years) underwent operative intervention for APS. Headaches and dizziness were the most common preoperative symptoms in the majority patients (14, 70%). Based on radiological features of MRI, the APS was classified into two subtypes, type A and type B. Seven patients (40%) in type A indicated a clear tumor margin, while 13 patients (60%) in type B showed an ill-defined margin. The surgical approach including frontal, temporal, and coronal frontal incisions for type A and type B tumors, respectively. Three patients in type A received total resection, while one patient in type B were total resected. Pathologically, 12 cases (60%, 12/20) were diagnosed as astrocytoma and 8 cases (20%, 8/20) were oligodendroglioma. Meanwhile, 17 cases (85%, 17/20) had MGMT promotor methylation. Conclusion In this study, we performed the first systematic research of patients with APS glioma. Most of patients with APS presented headaches and dizziness symptoms. The APS glioma was further divided into two major radiological subtypes with relevant different surgical approaches. The APS glioma in type A were more likely to receive total resection

Use of creep and recovery protocol to assess the printability of fibre-reinforced 3D printed white Portland cement composites

ABSTRACTWhite Portland cement is an ideal choice for producing 3D printed coloured composites due to its inherent whiteness. However, the uncontrollable rheological properties limit the establishment of printed structures and thus affect the mechanical properties. In this study, the polyvinyl alcohol (PVA) and polypropylene (PP) fibres were utilised as reinforcement materials in 3D printed white Portland cement composites (WPCCs) to improve the printability and toughness by controlling creep properties, aiming to build better printed structures. Experimental results show that the addition of PVA and PP fibres effectively improve the creep properties of WPCCs, and printed structures can be well built by controlling creep properties. Specifically, the thixotropy of WPCCs with PVA and PP fibre is improved within specific content ranges of 0∼1% and 0.4∼0.8%, respectively. Compared with reference sample, the flexural strength increases by approximately 148.8% and 90.2% when the PVA and PP fibre contents reach 1.25% and 1%, respectively