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Objective To investigate the value of CT enterography (CTE) in the diagnosis and differential diagnosis of small intestinal tumors and tumor-like lesions. Methods A retrospective analysis was performed for the imaging data of 74 patients who underwent CTE in our hospital from January 2015 to December 2022 and were diagnosed with small intestinal tumors and tumor-like lesions based on pathological examination, and according to the nature of lesions, they were divided into malignant tumor group with 54 patients and non-malignant+tumor-like lesion group with 20 patients. The two groups were compared in terms of major axis of tumor, intestinal residual rate, and CT values during plain scan phase, arterial phase, and venous phase. Results Compared with the non-malignant+tumor-like lesion group, the malignant tumor group had significantly higher major axis of tumor and CT value during plain scan phase (Z=-3.512,-3.214,P0.05). In the malignant tumor group, compared with the patients with adenocarcinoma, the patients with lymphoma had significantly higher major axis of tumor and intestinal residual rate (Z=-3.161,-4.853,P0.05). Conclusion CTE can fully display the features of small intestinal tumor and tumor-like lesions and thus provide a basis for the diagnosis and differential diagnosis of these diseases.

【Objective】 The rubber ring is a crucial component in fracturing pumps, yet it is highly prone to erosion. This study investigates the effects of fracturing particles on erosion and wear of the rubber ring. 【Method】 The study was based on the 3 500 HP fracturing pump. The fluid domain model for its valve body at the hydraulic end was developed using the finite element software COMSOL. The impact of the factors, including particle concentration, particle diameter, and angle of the valve body cone, on the erosion and wear of the rubber seal was analyzed. Mechanical models for a single particle and multi particle erosion of the rubber ring were established using the finite element software ABAQUS, which was used to analyzed the effects of particle shape, erosion speed, impact angle, and impact frequency on erosion and wear of the ring. 【Result】 ①To improve the resistance of the rubber ring against wear and erosion, the angle of the valve body cone should be more than 70°. We found that the lower the particle concentration was, the less susceptible the rubber ring was to wear. When the diameter of solid particles was doubled, the two-phase velocity was increased by about 25%, but this had little effect on the wear of the pump valve. ②Increasing the speed of erosion increased the erosion wear. The rubber ring was more likely to absorb the energy of sharp particles at low angle of attack, while it is more likely to absorb the energy of blunt particles at 90° impact. Under the impact of the multiple particles, blunt particles can cause fatigue failure of the rubber ring, while sharp particles can cause tensile failure of the material surface. 【Conclusion】 For the 3 500 HP fracturing pump we studied, the erosion and wear of the rubber ring can be ameliorated by reducing solid particle concentration, increasing the valve cone angle and roundness of the solid particles.

Based on the stress fluctuation during the tensile process of poly(butylene succinate) (PBS), the tensile behavior of biodegradable bicrystalline block copolyesters (PBSEG) synthesized using polycondensation of poly(ethylene glycol) (PEG) and poly(butylene succinate) (PBS) was further studied. The effects of tensile rate and temperature test conditions on the stress-strain behavior of bicrystalline block copolymer PBSEG were investigated by conducting tensile tests. The experimental results showed that when the mass content of polyethylene glycol in PBSEG was 60%, the material did not show obvious periodic stress fluctuation during the 'cold drawing' stage of the stress-strain curve, but showed different and more complicated periodic curve changes. The stress fluctuation of PBSEG copolyester had the characteristics of small amplitude and short period. The elongation at break increased obviously, and the maximum elongation at break was more than 2000%. The analysis of morphology and structure showed that the surface morphology of PBSEG dumbbell bars did not show obvious alternating changes in structure, characterized by light and dark. Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. The tensile fracture of the two materials occurred in the stress fluctuation region. Highlights * Small-amplitude and short-period stress fluctuation for PBSEG copolyester. * There was no alternating light and dark on the surface of the PBSEG stretched spline. * Craze was the main cause of ductile fracture for PBS and PBSEG copolyesters. * Tensile fracture of the materials occurred in the stress fluctuation region. KEYWORDS bicrystalline block copolymer, craze, poly(butylene succinate), poly(ethylene glycol), stress fluctuation, 1 | INTRODUCTION Some thermoplastic polymers exhibited a special tensile behavior during the stretching process. In the stretch neck stage, the stress was no longer constant, but showed a periodic [...]

Aging is an intricate process characterized by multiple hallmarks including stem cell exhaustion, genome instability, epigenome alteration, impaired proteostasis, and cellular senescence. Whereas each of these traits is detrimental at the cellular level, it remains unclear how they are interconnected to cause systemic organ deterioration. Here we show that abrogating Brap, a BRCA1-associated protein essential for neurogenesis, results in persistent DNA double-strand breaks and elevation of histone H2A mono- and poly-ubiquitination (H2Aub). These defects extend to cellular senescence and proteasome-mediated histone H2A proteolysis with alterations in cells' proteomic and epigenetic states. Brap deletion in the mouse brain causes neuroinflammation, impaired proteostasis, accelerated neurodegeneration, and substantially shortened the lifespan. We further show the elevation of H2Aub also occurs in human brain tissues with Alzheimer's disease. These data together suggest that chromatin aberrations mediated by H2Aub may act as a nexus of multiple aging hallmarks and promote tissue-wide degeneration.

[Objective] Through analying the causes of the current spatial pattern of cultivated land protection and its spatial correlation, the scientific zoning of cultivated land renovation planning was divided to provide reference for further optimizing the layout of cultivated land, improving the quality of cultivated land, and scientific utilization and protection of cultivated land. [Methods] Taking Kongtong District, Pingliang City, Gansu Province as an example, landscape pattern index method, multi-objective decision-making method, Spreaman rank correlation method and cluster analysis method were used to analyze the synergistic or tradeoff relationship between the current situation of cultivated land landscape pattern and its spatial existence by selecting cultivated land slope, cultivated land protection policy and urbanization impact, and to construct the correlation analysis and evaluation index system of cultivated land protection pattern. [Results] ① As a whole, the cultivated land landscape pattern index of the study area increased by 3.55% from 2010 to 2022, and the degree of cultivated land agglomeration showed a downward trend in most regions, but it fluctuated during the whole process. The regional land use degree showed an upward trend on the whole, and the characteristics of cultivated land layout and land use degree of each township were significantly different. ② The cultivated land protection index in 2022 increased by 315.30% compared with 2010, the cultivated land on 2°—6° slope increased by 120.96%, the cultivated land on 15°—25° slope decreased by 32.64%, and the cultivated land in > 25° decreased by 100%, which was highly coordinated with the cultivated land landscape pattern in space. The urbanization impact index showed an upward trend, which increased by 25.17% from 2010 to 2022. The urbanization impact on cultivated land distribution increased, and there was a significant spatial balance between urbanization and cultivated land landscape pattern. ③ Four units of cultivated land renovation planning were divided as cultivated land quality improvement key area, cultivated land quality improvement general area, cultivated land new development potential area, cultivated land coordination protection area. [Conclusion] The distribution characteristics of cultivated land in Kongtong District of Pingliang City, Gansu Province are different among different towns, and the overall protection effect of cultivated land is obvious. The main factors affecting the spatial pattern of cultivated land in the study area are policy factors, the impact of urban development, farmers’ planting willingness and cultivated land protection awareness, etc.