Search

Abstract There is a considerable difference in wall thickness between the mouth and the cavity of thin-walled and thick-mouthed seamless gas cylinders, and the existing manufacturing processes are unable to effectively meet product requirements. To overcome such issue, a step-by-step boring-necking-spinning solution for gas cylinders was proposed, in which sufficient wall thickness is reserved for the mouth area of the cylinder blank, followed by necking-spinning to realize the overall forming of thin-walled, thick-mouthed seamless gas cylinders. The stress–strain distribution and geometric dimensional changes of gas cylinders during the spinning process were investigated by means of finite element simulation, and the effects of different process parameters on the stress and wall thickness of the bottle mouth were analyzed. Further, multi-objective optimization of the response surface model was performed using the NSGA-II algorithm to derive a set of optimal process parameters. Finally, the correctness of the simulation and optimization results was verified experimentally, and the expected geometry and optimal strain state of the gas cylinder were obtained. The newly developed processing solution represents a groundbreaking advancement in the manufacturing of thin-walled and thick-mouthed gas cylinders.

Alpine natural heritage sites hold significant value due to their unique global resources. Studying land cover changes in these areas is crucial for maintaining and preserving multiple their values. This study takes Kalajun-Kuerdening, one of the components of Xinjiang Tianshan World Natural Heritage Site, as an example to analyze land cover changes and their driving factors in alpine heritage sites. Highlights include: (1) Between 1994 and 2023, Forest and Grassland increased by 55.96 km2 and 18.16 km2, with notable forest growth from 2007 to 2017. Trends in Forest changes align with forest protection policies, and a substantial amount of Bareland converted to Grassland indicates an increase in vegetation cover. (2) Elevation, precipitation, temperature, and evapotranspiration are key drivers of land cover changes, as validated by Random Forest algorithm and Geodetector model. (3) Favorable conditions for Grassland to Forest transition include annual precipitation between 275 and 375 mm, annual temperature between −2 and 3 °C, annual evapotranspiration between 580 and 750 mm, elevation between 1800 and 2600 m, and aspect between 0 to 110° and 220 to 259.9°. Continuous monitoring of land cover changes and their driving factors in mountain heritage sites contributes to the protection of the ecological environment and provides data and information support for addressing climate change, resource management, and policy making. [ABSTRACT FROM AUTHOR]

Many methods are used to locate preoperative small pulmonary nodules. However, deficiencies of complications and success rates exist. We introduce a novel magnetic gel for small pulmonary nodules localization in rabbit model, and furtherly evaluate its safety and feasibility. Rabbits were used as the experimental objects. A magnetic gel was used as a tracer magnet, mixed as sodium alginate-Fe3O4 magnetic fluid and calcium gluconate solution. In short-term localization, a coaxial double-cavity puncture needle was applied to inject the gel into the lung after thoracotomy, and a pursuit magnet made of Nd-Fe-B permanent magnetic materials was used to attract the gel representing location of the nodule. In long-term localization, the gel was injected under X-ray guidance. Imaging changes to the lung were observed under X-ray daily. Thoracotomy was performed to excise tissue containing the gel, and hematoxylin–eosin staining was used to observe the tissue on postoperative days 1, 3, 5, and 7. Observe tissues morphology of heart, liver, spleen, and kidney in the same way. The gel was formed after injection and drew lung tissue to form a protrusion from the lung surface under the applied magnetic field. No complication was observed. The shape and position of the gel had not changed when viewed under X-ray. Pathological analysis showed the gel had a clear boundary without diffusion of magnetic fluid. All tissues retained good histologic morphology and no magnetic fluid was observed. Our study preliminarily suggested that the technique using sodium alginate-Fe3O4 magnetic gel to locate small pulmonary nodules with guidance of X-ray, and to search for them under an applied magnetic field during the operation is safe and feasible. [ABSTRACT FROM AUTHOR]

In the present study, six commonly used promoters, including cytomegalovirus major immediate-early (CMV), the CMV enhancer fused to the chicken beta-actin promoter (CAG), human elongation factor-1α (HEF-1α), mouse cytomegalovirus (mouse CMV), Chinese hamster elongation factor-1α (CHEF-1α), and phosphoglycerate kinase (PGK), a CMV promoter mutant and a CAG enhancer, were evaluated to determine their effects on transgene expression and stability in transfected CHO cells. The promoters and enhancer were cloned or synthesized, and mutation at C-404 in the CMV promoter was generated; then all elements were transfected into CHO cells. Stably transfected CHO cells were identified via screening under the selection pressure of G418. Flow cytometry, qPCR, and qRT-PCR were used to explore eGFP expression levels, gene copy number, and mRNA expression levels, respectively. Furthermore, the erythropoietin (EPO) gene was used to test the selected strong promoter. Of the six promoters, the CHEF-1α promoter yielded the highest transgene expression levels, whereas the CMV promoter maintained transgene expression more stably during long-term culture of cells. We conclude that CHEF-1α promoter conferred higher level of EPO expression in CHO cells, but the CMV promoter with its high levels of stability performs best in this vector system. [ABSTRACT FROM AUTHOR]