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Planetary gear train is mainly used for power transmission, so it is of great significance to study its self-locking and efficiency. In this study, the self-locking analysis and efficiency maximization design of a 3K-H planetary gear train are carried out. Firstly, the efficiency of the positive and negative mechanism of the gear train is calculated using the transmission ratio method. Then, a unified formula for the efficiency of the planetary gear train is summarized. Furthermore, the efficiency curve is drawn by Matlab. Next, the trend of efficiency change of the planetary gear train and the conditions for realizing self-locking are analyzed. Finally, how to maximize the efficiency of the opposite mechanism under the condition of self-locking is studied.

Polyoxometalates (POMs) have shown great potential for applications in photocatalysis due to their unique structural features, tunable band gap, and environmental benignity. Herein, a Fe ion-incorporated Co4W6O21(OH)2·4H2O sphere network POM was successfully synthesized via a simple hydrothermal process. A DFT calculation proved that the Fe ion partially replaced cobalt atoms, forming FexCo4−xWOH, which played a crucial role in modulating the electron state and the band structure. The as-prepared FexCo4−xWOH exhibited excellent Fenton-like photocatalytic activity; the degradation rate of RhB improved 3.69 times compared with the sample without doping. The favorable performance of FexCo4−xWOH is a result of the synergistic effects of the Fenton reaction and the activation of H2O2 under visible irradiation, which can generate a mass of •O2− and •OH species in the unique sphere network structure. This study supplied a new idea for designing highly-active Fenton-like POM photocatalysts for environmental remediation. [ABSTRACT FROM AUTHOR]

Summary: Polyhydride electrocatalysts integrated directly into metal substrates have attracted attention because they can provide high electrochemical specific surface area and excellent mechanical properties. In this work, through the classical hydrothermal method and subsequent phosphating procedure, we synthesized for the first time an electrocatalyst with a pyramid‐shaped MnCO3 as the main structure, P and Co as co‐doping elements, named Co, P‐MnCO3, and used it as hydrogen evolution reaction (HER). The experimental results show that the excellent catalytic activity in alkaline media, with current densities of 10 and 200 mA∙cm−2 at 61 mV and 158 mV and low overpotentials, which are better than P‐Co (108/234 mV) and P‐MnCO3 (175 mV/340 mV), etc. it has more electrochemically active sites, faster charge transfer rate and lower resistance. The excellent electrochemical properties benefit from the unique highly active binary Co, P‐MnCO3 pyramid brick sites shortened the ion transfer distance and optimized synergistic effect between the doped metal elements (Co,P between MnCO3), the porous connection between Co, P‐MnCO3 and the high conductivity substrate, increased the electron‐transfer efficiency between the substrate and material, accelerating the conversion of H+ to H2; facilitated the release of bubbles and provided excellent mechanical properties for improved catalyst stability. This work provides a new idea for the synthesis of multi‐element electrocatalysts. [ABSTRACT FROM AUTHOR]

In order to solve the problems such as singleness of the absorption mechanism, difficulty of dispersion and inability of broadband absorption, carbon nanotubes were successfully prepared on the surface of acid oxidized carbon fiber by chemical grafting method. The effect of oxidation treatment on the carbon nanotubes modified carbon fiber and their electromagnetic properties were investigated. The results showed that the graft amount and graft efficiency of CNT were improved by oxidation treatment, resulting in the enhancement of the dielectric constant and the electromagnetic wave loss performance. At the condition of the nitric acid concentration of 65% and the reaction time of 8h, the grafted CNTs on the surface of CF reached 15.3% without agglomeration, which showed a good electromagnetic wave absorption property. [ABSTRACT FROM AUTHOR]

Due to the capability of perfect absorption, metamaterial becomes a hot research topic of wave absorbing materials in recent years. However, conventional metamaterials absorber is passive absorption and has the disadvantage that the wave-absorbing property can't be changed once the molding performed. Therefore, tunable metamaterials absorber gradually becomes one of the main research directions. Base on the research developments of tunable metamaterials absorber both of the domestic and foreign, several tunable methods were introduced in classification. Matrix structure and tunable mechanism was chief expounded. Furthermore, the tendency of change of wave absorbing characteristics curve and relationship between wave absorbing characteristics and effect factor were concluded. Finally, full text was summarized. The development trend of tunable metamaterials prospected. The important faction of tunable metamaterials absorber was explained. [ABSTRACT FROM AUTHOR]

Background: Research on the effects of intestinal microbiota transplantation (IMT) on chronic HBV infection (CHB) progression associated liver disease (HBV-CLD) and alterations in the microbiota post-IMT are quite limited for the moment., Methods: By integrating microbiome with metabolome analyses, we aimed to the function of IMT and the alterations of gut microbiota in patients with HBV-CLD. First, this study included 20 patients with HBV-CLD and ten healthy controls. Then, 16 patients with CHB were given IMT with donor feces (heterologous) via oral capsule. Fecal samples from CHB patients were obtained before and after IMT, as well as healthy controls, for 16S rDNA sequencing and untargeted metabolomics analysis., Results: The proalbuminemia were significantly increased after IMT, and the HBsAg and TBA showed a significant decrease after IMT in the HBV-CLD patients. There was statistical difference in the Chaol indexes between between CHB patients and healthy controls, suggesting a lower abundance of the gut microbiota in HBV-CLD patients. In addition, there was statistical difference in the Shannon and Simpson indexes between prior to IMT and post-IMT, indicating that the impaired abundance of the gut microbiota had been improved after IMT. The host-microbiota-metabolite interplay, amino acid metabolism, nicotinate and nicotinamide metabolism, starch and sucrose metabolism, steroid biosynthesis, and vitamins metabolism, were significantly lower in HBV-CLD patients than healthy controls., Conclusion: IMT may improve the therapeutic effects on patients HBV-CLD. Furthermore, IMT appears to improve amino acid metabolism by impaired abundance of the gut microbiota and therefore improve liver prealbumin synthesis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Deng, Guo, Chen, Li, Liu, Xia, Ou and Hong.)

Background and Objectives: Several recent clinical studies have indicated that vamorolone is comparable in effectiveness to glucocorticosteroids for treating Duchenne muscular dystrophy (DMD). However, there is a lack of extensive data regarding the efficacy and safety of various doses of vamorolone. We conducted a study to evaluate the efficacy of different doses of vamorolone in boys with DMD, and compare the safety of vamorolone vs. glucocorticosteroids, prednisone or deflazacort in boys with DMD., Methods: We performed systematic searches of the PubMed, Embase, and Cochrane Library databases for vamorolone, glucocorticosteroids, prednisone or deflazacort in boys with DMD. We assessed statistical heterogeneity across trials based on the Newcastle Ottawa scale (NOS) tool test and I 2 values, and mean differences were pooled using the random-effects model. We used traditional meta-analysis to evaluate efficacy and safety of vamorolone 6.0 mg/kg/d vs. vamorolone 2.0 mg/kg/d and vamorolone vs. prednisone. A network meta-analysis was applied to estimated the safety of vamorolone in comparison to glucocorticosteroids, prednisone and deflazacort. Our meta-analysis were performed using Revman 5.4 software, and our network meta-analysis were performed using Stata/MP 18.0., Results: In the meta-analysis, a total of 193 patients were analyzed across four clinical trials (97 patients receiving vamorolone 2 mg/kg per day; 96 patients receiving vamorolone 2 mg/kg per day). We observed that there were statistically significant differences in boys with DMD between vamorolone 6.0 mg/kg/d and vamorolone 2.0 mg/kg/d in TTSTANDV (MD = 0.03, 95%CI = 0.00-0.06, p  = 0.04), TTRWV (MD = 0.13, 95%CI = 0.08-0.19, p  < 0.01), 6MWT (MD = 24.54, 95%CI = 4.46-44.82, p  = 0.02), TTCLIMBV (MD = 0.04, 95%CI = 0.01-0.06, p  = 0.009), no significant difference in BMI z score (MD = 0.09, 95%CI = -0.03-0.20, p  = 0.13). Indirect comparisons derived from network meta-analysis did not show significant differences among vamorolone, glucocorticosteroids, prednisone and deflazacort in BMI z score., Conclusion: Our findings implied that boys with DMD who took vamorolone 6 mg/kg daily instead of 2 mg/kg daily may be safer and have superior motor function. However, more large sample randomized controlled trials are needed to confirm our results., Systematic Review Registration: This systematic review and meta-analysis has been registered in the International Prospective Register of Ongoing Systematic Reviews PROSPERO (registration number: CRD42024562916)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Zeng, Jiao, He, Li, Guo and Song.)