[μ-2,2′-Dimethyl-2,2′-(p-phenyl­ene)diprop­yl]bis­[chloridobis(2-methyl-2-phenyl­prop­yl)tin(IV)]

The mol­ecular structure of the title compound, [Sn2(C10H13)4(C14H20)Cl2], is a binuclear centrosymmetric complex, in which the Sn atoms are four-coordinated by three C atoms and one Cl atom in a distorted tetra­hedral geometry

A Novel Radial-Composite Model of Pressure Transient Analysis for Multistage Fracturing Horizontal Wells with Stimulated Reservoir Volume

In the process of stimulated reservoir volume of tight reservoir, horizontal well can form three zones, the inner zone is multistage fracturing zone, the middle zone is skin damage zone, and the outer zone is undamaged zone. In this paper, a transient well test analysis model of multistage fracturing horizontal well in three area composite reservoir is proposed. Based on Laplace transformation, point source integration, and superposition principle, the infinite conductivity multifracture model of three area composite reservoir is obtained. The linear equations of finite conductivity multifracture in Laplace space are established by using the equal conditions of flow and pressure at the fracture wall. Gauss-Newton iteration method and Stehfest number are used to obtain the solution of wellbore pressure. The accuracy of the results is verified by numerical simulation. Then, the flow characteristics of multistage fracturing horizontal wells in three area composite reservoirs are analyzed by type curves. The flow is divided into ten stages, which are the bilinear flow, the linear flow, the first radial flow stage, the inner zone linear flow, the inner zone radial flow, the middle zone linear flow, the middle zone radial flow, the outer zone linear flow, the outer zone radial flow, and the boundary dominated flow. The pressure derivative curves show different characteristics in different flow stages. The influences of fracture conductivity, fracture spacing, radius ratio of the middle zone to inner zone, radius ratio of the outer zone to the middle zone, permeability ratio of inner zone to the middle zone, permeability ratio of inner zone to outer zone, storage capacity ratio of inner zone to the middle zone, and storage capacity ratio of inner zone to outer zone on type curves are analyzed. Finally, the application and reliability of the proposed model are verified by a case example

Rate Decline Analysis of Horizontal Wells with Multiple Variable Conductivity and Uneven Distributed Fractures

In this paper, a new rate decline analysis model of horizontal wells with variable conductivity and uneven distribution of multiple fractures is proposed. By Laplace transformation, point source integration, and superposition principle, solutions of multiple infinite conductivity fractures in closed reservoirs are obtained. By coupling Fredholm integral equation of variable conductivity, linear equations of variable conductivity fractures in Laplace space are obtained. Gauss-Newton iteration, Duhamel convolution, and Stehfest numerical inversion method are used to obtain the bottom hole production solution. The accuracy of the results is verified by comparing with Eclipse software simulation. Then, the influence of some important reservoir and fracture parameters on the production is analyzed. The calculative results show that the smaller the fracture spacing is, the earlier the fracture begins to decline, the more the production will decrease; the change of different fracture length with the total fracture length unchanged has almost no effect on the production; the angle between fracture and x-axis has an important effect on the production; the smaller the angle between fracture and x-axis is, the stronger the interference between fractures is, the higher the production; the initial fracture conductivity affects the early production behavior, and the higher the initial fracture conductivity, the higher the production; the larger the fracture declines index, the lower the production, but the decreasing range gradually decreases with the increase of the decline index; the larger the reservoir drainage radius, the later the energy depletion stage, the higher the production. At last, a good fitting effect is obtained by fitting an example of oil field. The model proposed in this paper enriches the model base of rate decline analysis of fractured horizontal wells and lays a theoretical foundation for efficient development and practice of tight reservoirs

Celastrol Combats Methicillin‐Resistant Staphylococcus aureus by Targeting Δ1‐Pyrroline‐5‐Carboxylate Dehydrogenase

Abstract The emergence and rapid spread of methicillin‐resistant Staphylococcus aureus (MRSA) raise a critical need for alternative therapeutic options. New antibacterial drugs and targets are required to combat MRSA‐associated infections. Based on this study, celastrol, a natural product from the roots of Tripterygium wilfordii Hook. f., effectively combats MRSA in vitro and in vivo. Multi‐omics analysis suggests that the molecular mechanism of action of celastrol may be related to Δ1‐pyrroline‐5‐carboxylate dehydrogenase (P5CDH). By comparing the properties of wild‐type and rocA‐deficient MRSA strains, it is demonstrated that P5CDH, the second enzyme of the proline catabolism pathway, is a tentative new target for antibacterial agents. Using molecular docking, bio‐layer interferometry, and enzyme activity assays, it is confirmed that celastrol can affect the function of P5CDH. Furthermore, it is found through site‐directed protein mutagenesis that the Lys205 and Glu208 residues are key for celastrol binding to P5CDH. Finally, mechanistic studies show that celastrol induces oxidative stress and inhibits DNA synthesis by binding to P5CDH. The findings of this study indicate that celastrol is a promising lead compound and validate P5CDH as a potential target for the development of novel drugs against MRSA

Rotation-Facilitated Rapid Transport of Nanorods in Mucosal Tissues

Mucus is a viscoelastic gel layer that typically protects exposed surfaces of the gastrointestinal (GI) tract, lung airways, and other mucosal tissues. Particles targeted to these tissues can be efficiently trapped and removed by mucus, thereby limiting the effectiveness of such drug delivery systems. In this study, we experimentally and theoretically demonstrated that cylindrical nanoparticles (NPs), such as mesoporous silica nanorods and calcium phosphate nanorods, have superior transport and trafficking capability in mucus compared with spheres of the same chemistry. The higher diffusivity of nanorods leads to deeper mucus penetration and a longer retention time in the GI tract than that of their spherical counterparts. Molecular simulations and stimulated emission of depletion (STED) microscopy revealed that this anomalous phenomenon can be attributed to the rotational dynamics of the NPs facilitated by the mucin fibers and the shear flow. These findings shed new light on the shape design of NP-based drug delivery systems targeted to mucosal and tumor sites that possess a fibrous structure/porous medium

<i>OsWRKY97,</i> an Abiotic Stress-Induced Gene of Rice, Plays a Key Role in Drought Tolerance

Drought stress is one of the major causes of crop losses. The WRKY families play important roles in the regulation of many plant processes, including drought stress response. However, the function of individual WRKY genes in plants is still under investigation. Here, we identified a new member of the WRKY families, OsWRKY97, and analyzed its role in stress resistance by using a series of transgenic plant lines. OsWRKY97 positively regulates drought tolerance in rice. OsWRKY97 was expressed in all examined tissues and could be induced by various abiotic stresses and abscisic acid (ABA). OsWRKY97-GFP was localized to the nucleus. Various abiotic stress-related cis-acting elements were observed in the promoters of OsWRKY97. The results of OsWRKY97-overexpressing plant analyses revealed that OsWRKY97 plays a positive role in drought stress tolerance. In addition, physiological analyses revealed that OsWRKY97 improves drought stress tolerance by improving the osmotic adjustment ability, oxidative stress tolerance, and water retention capacity of the plant. Furthermore, OsWRKY97-overexpressing plants also showed higher sensitivity to exogenous ABA compared with that of wild-type rice (WT). Overexpression of OsWRKY97 also affected the transcript levels of ABA-responsive genes and the accumulation of ABA. These results indicate that OsWRKY97 plays a crucial role in the response to drought stress and may possess high potential value in improving drought tolerance in rice