Metal-like behavior of a 2D molecular catalyst enables redox-decoupled electrocatalysis

Molecular catalysts facilitate electrochemical conversion by changing their oxidation states to transfer electrons. However, this redox-mediated mechanism features stepwise electron transfer and substrate activation in separate elementary steps, thereby resulting in an inherent loss in efficiency. Here, we synthesize a two-dimensional (2D) iron phthalocyanine (FePc) material and uncover its non-mediated electron transfer behavior in electrocatalysis, which overcomes the conventional redox-mediated limitation in the oxygen reduction reaction (ORR) pathway that molecular catalysts face. The 2D geometry enables the FePc molecules to be positioned within the electrochemical double layer, enabling electrons to directly transfer to oxygen reactants, prior to the Fe(II/III) redox. This functions in a manner akin to a metal catalyst thereby opening a redox-decoupled ORR mechanism. As a result, the reported 2D FePc molecular catalyst exhibits unprecedented ORR half-wave potential at 0.945 V vs. the reversible hydrogen electrode, achieving efficient application in zinc-air batteries and H2/O2 fuel cells. These findings open new possibilities in voltage efficient, redox-decoupled molecular catalysis that integrates strengths of molecules and materials in one synergistic system.</p

Spatio-temporal characteristics of PM\u3csub\u3e2.5\u3c/sub\u3e, PM\u3csub\u3e10\u3c/sub\u3e, and AOD over the central line project of China’s South-NorthWater diversion in Henan Province (China)

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The spatio-temporal characteristics of particulate matter with a particle size less than or equal to 2.5 µm (PM2.5), particulate matter with a particle size less than or equal to 10 µm (PM10), meteorological parameters from September 2018 to September 2019, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) aerosol optical depth (AOD) from 2007 to 2019 were investigated over the Central Line Project of China’s South-North Water Diversion (CSNWD) in Henan Province. To better understand the characteristics of the atmospheric environment over the CSNWD, air quality monitoring stations were installed in Nanyang (in the upper reaches), Zhengzhou (in the middle reaches), and Anyang (in the lower reaches). In this study, daily, monthly, and seasonal statistical analyses of PM2.5 and PM10 concentrations were performed and their relationship with meteorological parameters was investigated. The results show extremely poor air quality conditions over the Zhengzhou Station compared with the Nanyang and Anyang Stations. The annual average PM2.5 concentration did not meet China’s ambient air secondary standard (35 µg/m3 annual mean) over all the stations, while the annual average PM10 concentration satisfied China’s ambient air secondary standard (100 µg/m3 annual mean) over the Anyang and Nanyang Stations, except for the Zhengzhou Station. The highest PM2.5 and PM10 concentrations were observed during winter compared with the other seasons. The results show that PM2.5 and PM10 concentrations were negatively correlated with wind speed and temperature at the Nanyang and Zhengzhou Stations, but positively correlated with relative humidity. However, no significant negative or positive correlation was observed at Anyang Station. There is a strong linear positive correlation between PM2.5 and PM10 (R = 0.99), which indicates that the particulate matter at the three stations was mainly caused by local emissions. Additionally, the AOD values at the three stations were the highest in summer, which may be related to the residues of crops burned in Henan Province in summer

PACAP/PAC1 regulation in cystitis rats: induction of bladder inflammation cascade leading to bladder dysfunction

IntroductionInterstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a chronic and debilitating condition marked by bladder pain, urinary urgency, and frequency. The pathophysiology of IC/BPS remains poorly understood, with limited therapeutic options available. The role of Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and its receptor PAC1 in IC/BPS has not been thoroughly investigated, despite their potential involvement in inflammation and sensory dysfunction. This study aims to examine the expression and functional role of the PACAP/PAC1 signaling pathway in the pathogenesis of IC/BPS.MethodsBladder tissue samples from IC/BPS patients and a rat model of cystitis were analyzed to evaluate PACAP and PAC1 expression. Transcriptomic analysis, immunohistochemistry, and bladder function assays were employed to assess the correlation between PACAP/PAC1 activation, bladder inflammation, and sensory dysfunction. Additionally, modulation of the PACAP/PAC1 pathway was tested in rats to determine its effects on bladder inflammation and function.ResultsOur results demonstrate significant upregulation of PACAP and PAC1 in both human bladder tissues from IC/BPS patients and in the rat cystitis model. This upregulation was associated with increased bladder inflammation and sensory dysfunction. Intervention with PACAP/PAC1 pathway modulation in rats resulted in a marked reduction in bladder inflammation and improvement in bladder function, suggesting the pathway’s pivotal role in disease progression.DiscussionThe findings provide compelling evidence that the PACAP/PAC1 pathway is involved in the inflammatory and sensory changes observed in IC/BPS. By targeting this signaling pathway, we may offer a novel therapeutic approach to mitigate the symptoms of IC/BPS. This study enhances our understanding of the molecular mechanisms driving IC/BPS and opens avenues for the development of targeted treatments

Action Mechanisms of Binary Combinations of Four Tyrosinase Inhibitors

To investigate the combined inhibitory effects of sophoroside (Sop), puerarin (Pue), mangiferin (Man), and kojic acid (KA) on tyrosinase (TYR), we determined the combination index (CI). Competitive binding experiments were done to evaluate the effect of the order of addition of TYR inhibitors on their binding to TYR, and the mechanism of the combined action of TYR inhibitors was explored by various spectroscopies. The results showed that the combinations of Pue + Sop, Sop + KA, and KA + Man exhibited a synergistic inhibitory effect on TYR, with addition orders of TYR-Pue-Sop, TYR-Sop-KA, and TYR-KA-Man. All inhibitor combinations statically quenched the fluorescence of TYR, forming a ternary complex. The binding constant of Pue + Sop to TYR was not significantly different from that of Sop, and the number of binding sites was approximately to 1, indicating that the binding sites of the two inhibitors were different. As evidenced by increased binding constant and decreased particle size, Sop and KA promoted the binding of KA and Man to TYR, respectively, which consequently became tighter. The interaction type of one inhibitor was not changed by the presence of another. Electrostatic interaction was dominant in TYR-Pue-Sop, hydrogen bond and van der Waals force in TYR-Sop-KA and hydrophobic interaction in TYR-KA-Man. Infrared spectroscopy showed that compared with TYR, TYR-Sop-KA and TYR-Pue-Sop tended to transit towards disorder, and the structure of TYR-KA-Man was more unstable. The results of differential scanning calorimetry (DSC) showed that the melting temperature (Tm) of the TYR-inhibitor ternary complexes was lower than that of the binary complexes, indicating decreased thermal stability. In conclusion, an increase in the binding constant of one TYR inhibitor and a decrease in the thermal stability of complexes in the presence of another may be reasons for the synergistic action of the two TYR inhibitors

Optimal Design of the Flow Field of Bi-center Bit

AbstractBottom-hole flow field is determined by the hydraulic structure of PDC bit, it is one of the important factors that affect the performance of the bit. The flow field optimizing is an important means of improving the hydraulic performance of drill bit. Because of the complicated structure, the performance of bi-center bit is different from conventional bit, thus its flow field is necessary to be optimized. In this paper, an evaluation method of the bottom-hole flow field of the bi-center bit is proposed, the relationships between flow distribution, nozzle angle and cuttings carrying effect are studied with numerical simulation method, the reflux distributions of the bottom-hole flow field are obtained under the different combinations of different size nozzles and nozzle spray angles, the hydraulic structure of the bit is optimized according to the numerical simulation results, then an optimal hydraulic structure of bi-center bit is obtaine

Research on Maneuvering Motion Prediction for Intelligent Ships Based on LSTM-Multi-Head Attention Model

In complex marine environments, accurate prediction of maneuvering motion is crucial for the precise control of intelligent ships. This study aims to enhance the predictive capabilities of maneuvering motion for intelligent ships in such environments. We propose a novel maneuvering motion prediction method based on Long Short-Term Memory (LSTM) and Multi-Head Attention Mechanisms (MHAM). To construct a foundational dataset, we integrate Computational Fluid Dynamics (CFD) numerical simulation technology to develop a mathematical model of actual ship maneuvering motions influenced by wind, waves, and currents. We simulate typical operating conditions to acquire relevant data. To emulate real marine environmental noise and data loss phenomena, we introduce Ornstein&ndash;Uhlenbeck (OU) noise and random occlusion noise into the data and apply the MaxAbsScaler method for dataset normalization. Subsequently, we develop a black-box model for intelligent ship maneuvering motion prediction based on LSTM networks and Multi-Head Attention Mechanisms. We conduct a comprehensive analysis and discussion of the model structure and hyperparameters, iteratively optimize the model, and compare the optimized model with standalone LSTM and MHAM approaches. Finally, we perform generalization testing on the optimized motion prediction model using test sets for zigzag and turning conditions. The results demonstrate that our proposed model significantly improves the accuracy of ship maneuvering predictions compared to standalone LSTM and MHAM algorithms and exhibits superior generalization performance

Numerical Simulation Analysis of Wellbore Stability in Weak Interlayer of Igneous Rock

Wellbores drilled in igneous formation with weak interlayers face significant risk of instabilities. This study aims to investigate the underlying mechanisms of these instabilities by employing a combination of rock mechanics tests and numerical simulation techniques. The mechanical properties of igneous rocks are evaluated to determine core strength parameters and analyze the impact of drilling fluid immersion on core strength. The two-dimensional model of the igneous formation is refined, and theoretical derivations are made, including the linear elasticity principal equation and the extent of the plastic zone within the wellbore. A numerical simulation model is developed using ABAQUS to analyze the wellbore stability of the weak interlayer igneous formation, accounting for drilling fluid immersion and weak interlayer conditions. The numerical simulations focus on four key aspects of the weak interlayer formation: strength, permeability, horizontal in-situ stress anisotropy, and abnormal pore pressure. The study findings indicate that strengthening the weak interlayer effectively mitigates the risk of wellbore instability. Moreover, the permeability of the weak interlayer exhibits minimal impact on wellbore stability within the formation. However, an increase in horizontal in-situ stress anisotropy and the abnormal pore pressure both decrease wellbore stability along the direction of the maximum in-situ stress

High-dose Vitamin C inhibits PD-L1 expression by activating AMPK in colorectal cancer

Vitamin C (VitC) has elicited considerable interest regarding its potential role in cancer therapy; however, its effects on tumor immunity remain unclear. In colorectal cancer (CRC), although anti-PD-1/PD-L1 therapies demonstrate promise, their efficacy is still constrained. Our prior research demonstrated that VitC can inhibit tumor growth by suppressing the Warburg effect. This study aims to explore the effects of high-dose VitC on PD-L1 expression in CRC, focusing on its underlying mechanisms and potential for enhancing immunotherapy. We found that VitC inhibits aerobic glycolysis in HCT116 cells while also downregulating PD-L1 expression. Further investigations indicated that this process is mediated by VitC's activation of AMPK, which downregulates HK2 and NF-κB, ultimately resulting in reduced PD-L1 expression and increased T cell infiltration. Notably, we observed that VitC and the PD-L1 monoclonal antibody atezolizumab exhibit comparable tumor-inhibiting abilities, and their combined use further enhances this efficacy. In conclusion, our results demonstrate that high-dose VitC activates AMPK, downregulates PD-L1 expression, mitigates immune evasion, and suppresses tumor growth. This provides a promising strategy for optimizing immunotherapy in CRC