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In order to solve the problem of roof caving during the excavation of the roadway of Tenghui 2# coal passing through the old goaf, the research on the evolution law of the displacement field and stress field of the roof and floor during the heading face to reveal the old goaf was carried out. The stress state and affected range of the tunneling roadway at different stages during the disclosure of the old goaf were obtained by combining theoretical calculation, on-site monitoring and numerical simulation, and the support scheme of the tunneling roadway over the old goaf was determined. The calculation results show that there is a plastic area of 5-10 m at the edge of the old goaf in the coal seam, and when the roadway continues to advance towards the old goaf, the stress state of the columnar coal body between the heading face and the old goaf changes from elastic to plastic. The evolution trend of roof and floor displacement is not synchronized during roadway excavation, and the deformation rate of roof displacement increases by 20% as the roadway gets closer to the goaf, and the deformation rate of the floor gradually decreases as the heading face approaches the goaf until it reaches a stable value. The field experimental results show that the increase of the relative deformation of the top and bottom plates in 50 d is controlled at 25 mm, and the increase of the relative deformation of the two groups is controlled at 23 mm, and the deformation of the surrounding rock of the roadway is effectively controlled.

Objective To obtain the non-structure protein 14 (Nsp14) of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) with higher purity and enzymatic activity. Methods This study firstly analyzed the rare codons in the gene of nsp14 according to the codon usage bias of E. coli, followed by codon optimization. The optimized nucleotide fragment of nsp14 was cloned into four kinds of expressing vectors respectively. Comparative analysis of yield and solubility was performed among these expressed four fusion proteins. The best one was chosen for further optimization of expressing conditions. After the fusion protein was purified by glutathione affinity column, the fusion tag was removed by 3C protease, and then the protein was purified by glutathione affinity column and molecular sieve column for further analysis of enzymatic activity through urea polyacrylamide gel electrophoresis. Results Many rare codons were found in expression of SARS-CoV-2 nsp14 in E. coli, among which some rare codons were distributed in close range and tandem. The best recombinant plasmid for expressing the fusion protein was pGEX6P1-GST-OPTI-Nsp14, which gave an eptimal expression in 30 ℃ with high yield and solubility. After purification, a higher purity of Nsp14 with nuclease activity was obtained. Conclusions This study shows that the SARS-CoV-2 Nsp14 protein with nuclease activity is successfully prepared, which lays a foundation for the further research on the structure and function of SARS-CoV-2 Nsp14, and provides favorable conditions for screening antiviral drugs targeting at Nsp14 of SARS-CoV-2.

The behavior of void surface healing in 316LN steel samples undergoing thermal plasticity deformation was investigated using the Gleeble 1500 thermomechanical simulator. The characterization of the void surface after plastic deformation was analyzed under different deformation temperatures, deformation amounts, and holding time durations. The morphology evolution and microstructure of the void surface healing zone during thermal plasticity deformation and holding time duration stage were analyzed using electron back scatter diffraction imaging. The mechanism of void surface healing under thermal plasticity deformation was investigated. It was found that the degree of void surface healing increases with the degree of deformation and the duration of the holding time. Dynamic recrystallization occurred continuously at the void surface, resulting in a plethora of crystal defects and a substantial amount of energy. These conditions were conducive to atomic diffusion and migration, thereby promoting the healing process of the void surface. Maintaining high temperature after deformation can continue to provide energy for the diffusion and migration of atoms, promotes the growth of recrystallized grains, and gradually heals the void surface.

A Janus TaO/TaN heterojunction hybrid with graphene exhibited excellent activity, selectivity and durability for the 2e− oxygen reduction reaction (ORR), compared to TaON@Gr, due to the optimized O2 adsorption and favored *OOH binding in the Janus TaO/TaN heterojunction. This provides a new approach for the structural design of high-performance 2e− ORR catalysts. [ABSTRACT FROM AUTHOR]

Droplet manipulation is a multidisciplinary field with broad applications across various industries. It holds significant potential in areas such as microfluidics, oil–water separation, water harvesting, and heat transfer. However, there is still a lack of comprehensive knowledge regarding droplet migration on restricted surfaces. In this study, we conducted a numerical simulation using the front-tracking method to investigate the heat transfer associated with droplet migration on a cold plate with a wettability gradient. We examined the effects of relative temperature differences, surface wettability, low initial impact velocities (W e ≤ 10), and wettability constraints (the width of the wettability stripe capable of driving droplet movement) on various droplet-related heat transfer characteristics and the resulting temperature field distribution. Our key findings indicate that as the temperature difference between the droplet and the surface increases, the heat flux experienced by the droplet after deposition also increases. Additionally, the decline in the heat flux curve during the descending phase becomes more significant. The surface contact angle plays a crucial role in the heat transfer dynamics during droplet migration. Droplets reach thermal equilibrium more quickly on hydrophilic surfaces with smaller contact angles. Higher initial impact velocities initially cause droplets to rebound on the surface, leading to more pronounced fluctuations in transient heat flux during the impact phase. However, as droplets transition from the rebound phase to the migration phase, the impact velocity's influence diminishes. Additionally, the restricted wettability ( W * ) affects the droplet-surface heat transfer through variations in the wetting area. We observed a fourfold difference in the relative wetting area between W * = 0. 4 and W * = 2. 5 in the final stage. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is one of the deadliest primary brain tumors, but its diagnosis and curative therapy still remain a big challenge. Herein, neutrophil‐targeting semiconducting polymer nanotheranostics (SSPNiNO) is reported for second near‐infrared (NIR‐II) fluorescence imaging‐guided trimodal therapy of orthotopic glioblastoma in mouse models. The SSPNiNO are formed based on two semiconducting polymers acting as NIR‐II fluorescence probe as well as photothermal conversion agent, respectively. A thermal‐responsive nitric oxide (NO) donor and an adenosine 2A receptor (A2AR) inhibitor are co‐integrated into SSPNiNO to enable trimodal therapeutic actions. SSPNiNO are surface attached with a neutrophil‐targeting ligand to mediate their effective delivery into orthotopic GBM sites via a "Trojan Horse" manner, enabling high‐sensitive NIR‐II fluorescence imaging. Upon NIR‐II light illumination, SSPNiNO effectively generates heat via NIR‐II photothermal effect, which not only kills tumor cells and induces immunogenic cell death (ICD), but also triggers controlled NO release to strengthen tumor ICD. Additionally, the encapsulated A2AR inhibitor can modulate immunosuppressive tumor microenvironment by blocking adenosine‐A2AR pathway, which further boosts the antitumor immunological effect to observably suppress the orthotopic GBM progression. This study can provide a multifunctional theranostic nanoplatform with cumulative therapeutic actions for NIR‐II fluorescence imaging‐guided effective GBM treatment. [ABSTRACT FROM AUTHOR]

The manufacturing technique of the top coal caving in coal mining of the upper and lower gateway in the working face is mainly along the coal seam bottom plate excavation. On the basis of the tunneling equipment used in the comprehensive tunneling face, our mine has developed the supporting technology and equipment of temporary support for rapid tunneling of top coal, that is, temporary support for rapid tunneling of top coal. Its purpose is to expand the area of temporary roof support, to realize the timely support of the new exposed roof cut by the roadheader, facilitate the parallel operation of various processes, protect the safety of personnel and equipment in the working space, shorten the operation time of permanent support, improve the efficiency of tunneling support work, accelerate the tunneling face tunneling speed. In order to ensure the safety of the workers in the tunneling face, the temporary support for rapid tunneling of top coal manufactured by SolidWorks software is checked and analyzed, which proves that the newly developed temporary support for rapid tunneling of top coal is safe and reliable.

The slip of the packer is the core part of the anchoring system. Unreasonable design of the slip structure can easily cause damage to the anchor claw of the slip, unstable anchoring, and even damage to the casing. At present, the main methods of slip anchoring performance tests are indoor design and field tests, and slips with different structural parameters need to be processed to verify their anchoring performance. In order to ensure that the slips can play a good anchoring effect and reduce the damage to the casing, this study uses a combination of finite element analysis, BP&NSGA-II, and indoor tests to study the mechanical behavior of the slips during the anchoring process. A prediction model was established to optimize the key parameters affecting anchoring performance, such as slip angle, inclination angle, inner cone angle, the radius of curvature, and spacing. Indoor experiments show that the prediction method can greatly improve the efficiency and accuracy of the design and test the anchoring performance of slips.