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In order to solve the problems of the traditional output structure of the cycloid pinion transmission, such as easy damage and complex structure, a new type of cycloid pinion gear is proposed by applying the internal and external cycloid tooth profile to the field of NN-type less differential planetary gear transmission, and the analysis of its tooth profile characteristics and meshing characteristics is carried out. The equations of the tooth profile equation and pressure angle of the cycloid are derived, and the influence of the tooth profile parameters on the pressure angle is analyzed to lay the foundation for the application of this new transmission system. The parameter equations of the inner and outer cycloid gears under different tooth profile modification methods are derived, and the simulation analysis is carried out using Matlab software to solve the meshing gap problem due to a series of reasons such as lubrication mucosa and manufacturing errors. Finally, the mechanical characteristics of the double cycloid needle gear transmission are analyzed, which provides a theoretical basis for the subsequent design of the reducer and finite element analysis. This study has significance and engineering use value for the development of new transmission methods.

In order to solve the problems of the traditional output structure of the cycloid pinion transmission, such as easy damage and complex structure, a new type of cycloid pinion gear is proposed by applying the internal and external cycloid tooth profile to the field of NN-type differential less planetary gear transmission, and the analysis of its tooth profile characteristics and meshing characteristics is carried out. The equations of the tooth profile equation and pressure angle of the cycloid are derived, and the influence of the tooth profile parameters on the pressure angle is analyzed to lay the foundation for the application of this new transmission system; the parameter equations of the internal and external cycloid gears under different tooth profile modification methods are derived, and the simulation analysis is carried out using Matlab software to solve the meshing gap problem due to a series of reasons such as lubrication mucosa and manufacturing errors; finally, the mechanical characteristics of the double cycloid needle gear transmission are analyzed, which provides a theoretical basis for the subsequent design of the gearbox and finite element analysis. The study has significance and engineering use value for the development of new transmission methods.

Combining the linear conjugate tooth profile with the planetary gear transmission with small tooth difference, taking the linear conjugate small tooth difference planetary gear reducer as the research object, the structure natural frequency and vibration mode of the reducer are obtained through finite element modal analysis, which shows the reducer has good structural dynamic characteristics; through the simulation analysis of vibration characteristics, the vibration law of the reducer under typical working conditions is obtained, and the vibration test experiment is carried out. The vibration experiment results are consistent with the simulation results. The vibration characteristics research results show that the input speed has a significant impact on the vibration amplitude and frequency of the linear conjugate small tooth difference planetary gear reducer.

Electrochromic polymers (ECPs) have great application potential in flexible displays, and there is an increasing expectation of using green methods to form ECP films. Herein, we propose a modified microemulsion method to prepare cyan/magenta/yellow (C/M/Y) water-dispersed electrochromic polymer nanoparticles (WDEN) systems. Three polymer films (WDECP-C/M/Y) maintain similar electrochemical properties compared to their corresponding organic solvent-based polymer films. It is intriguing that WDECP-C/M/Y exhibit better electrochromic properties in terms of higher cycling stability (97.24%, 95.05%, and 52.84%, respectively) and faster switching time (0.94 s, 1.09 s, and 1.34 s for coloring time, respectively) due to the introduction of nanoparticles. In addition, it can achieve various desired colors by blending the C/M/Y WDEN systems in different ratios. The calculated chromaticity coordinates of the blending polymer films show close values to the experimental observation, and the calculated Δ E * ab values range from 2.6 to 10.3, which may provide theoretical guidance for precisely color control. Finally, large-scale and patterned devices were assembled, which can achieve colored-to-colorless reversible electrochromism at a low driving voltage of 0–1.5 V. This work puts forward a universal and environmentally sustainable strategy to prepare WDEN systems, demonstrating their wide range of applications in display devices and electronic tags. [ABSTRACT FROM AUTHOR]

Matrix metalloproteinases (MMPs), particularly gelatinases (MMP-2/-9), are involved in neurovascular impairment after stroke. Detection of gelatinase activity in vivo can provide insight into blood-brain barrier disruption, hemorrhage, and nerve cell injury or death. We applied gelatinase-activatable cell-penetrating peptides (ACPP) with a cleavable l-amino acid linker to examine gelatinase activity in primary neurons in culture and ischemic mouse brain in vivo We found uptake of Cy5-conjugated ACPP (ACPP-Cy5) due to gelatinase activation both in cultured neurons exposed to n-methyl-d-aspartate and in mice after cerebral ischemia. Fluorescence intensity was significantly reduced when cells or mice were treated with MMP inhibitors or when a cleavage-resistant ACPP-Cy5 was substituted. We also applied an ACPP dendrimer (ACPPD) conjugated with multiple Cy5 and/or gadolinium moieties for fluorescence and magnetic resonance imaging (MRI) in intact animals. Fluorescence analysis showed that ACPPD was detected in sub-femtomole range in ischemic tissues. Moreover, MRI and inductively coupled plasma mass spectrometry revealed that ACPPD produced quantitative measures of gelatinase activity in the ischemic region. The resulting spatial pattern of gelatinase activity and neurodegeneration were very similar. We conclude that ACPPs are capable of tracing spatiotemporal gelatinase activity in vivo, and will therefore be useful in elucidating mechanisms of gelatinase-mediated neurodegeneration after stroke.

Xinnaotongluo liquid has been used to improve the clinical symptoms of patients with myocardial infarction. However, the molecular mechanism of Xinnaotongluo liquid is not completely understood. H9c2 cells exposed to hypoxia/reoxygenation (H/R) was used to simulate damage to cardiomyocytes in myocardial infarction in vitro. The biological indicators of H9c2 cells were measured by cell counting kit-8, enzyme linked immunoabsorbent assay, and western blot assay. In H/R-induced H9c2 cells, a markedly reduced murine double minute 2 (MDM2) was observed. However, the addition of Xinnaotongluo liquid increased MDM2 expression in H/R-induced H9c2 cells. And MDM2 overexpression strengthened the beneficial effects of Xinnaotongluo liquid on H9c2 cells from the perspective of alleviating oxidative damage, cellular inflammation, apoptosis and ferroptosis of H/R-induced H9c2 cells. Moreover, MDM2 overexpression reduced the protein expression of p53 and Six-Transmembrane Epithelial Antigen of Prostate 3 (STEAP3). Whereas, STEAP3 overexpression hindered the function of MDM2-overexpression in H/R-induced H9c2 cells. Our results insinuated that Xinnaotongluo liquid could protect H9c2 cells from H/R-induced damage by regulating MDM2/STEAP3, which provide a potential theoretical basis for further explaining the working mechanism of Xinnaotongluo liquid. [ABSTRACT FROM AUTHOR]

Background: Our previous research shows that Curcumin (CUR) attenuates myocardial ischemia-reperfusion injury (MIRI) by reducing intracellular total RNA m6A levels. However, the mechanism remains unknown. Methods: For ischemia-reperfusion (IR), H9c2 cells were cultured for 6 h in serum-free low-glycemic (1 g/L) medium and a gas environment without oxygen, and then cultured for 6 h in high-glycemic (4.5 g/L) medium supplemented with 10% FBS and a 21% oxygen environment. The effects of different concentrations of CUR (5, 10, and 20 µM) treatments on signaling molecules in conventionally cultured and IR-treated H9c2 cells were examined. Results: CUR treatment significantly up-regulated the H2S levels, and the mRNA and protein expression of cystathionine γ-lyase (CSE), and down-regulated the mRNAs and proteins levels of thiosulfate sulfurtransferase (TST) and ethylmalonic encephalopathy 1 (ETHE1) in H9c2 cells conventionally cultured and subjected to IR. Exogenous H2S supply (NaHS and GYY4137) significantly reduced intracellular total RNA m6A levels, and the expression of RNA m6A "writers" METTL3 and METTL14, and increased the expression of RNA m6A "eraser" FTO in H9c2 cells conventionally cultured and subjected to IR. CSE knockdown counteracted the inhibitory effect of CUR treatment on ROS production, promotion on cell viability, and inhibition on apoptosis of H9c2 cells subjected to IR. Conclusion: CUR attenuates MIRI by regulating the expression of H2S level-regulating enzymes and increasing the endogenous H2S levels. Increased H2S levels could regulate the m6A-related proteins expression and intracellular total RNA m6A levels. [ABSTRACT FROM AUTHOR]

Redox-mediated posttranslational modifications represent a molecular switch that controls major mechanisms of cell function. Nitric oxide (NO) can mediate redox reactions via S-nitrosylation, representing transfer of an NO group to a critical protein thiol. NO is known to modulate neurogenesis and neuronal survival in various brain regions in disparate neurodegenerative conditions. However, a unifying molecular mechanism linking these phenomena remains unknown. Here, we report that S-nitrosylation of myocyte enhancer factor 2 (MEF2) transcription factors acts as a redox switch to inhibit both neurogenesis and neuronal survival. Structure-based analysis reveals that MEF2 dimerization creates a pocket, facilitating S-nitrosylation at an evolutionally conserved cysteine residue in the DNA binding domain. S-Nitrosylation disrupts MEF2-DNA binding and transcriptional activity, leading to impaired neurogenesis and survival in vitro and in vivo. Our data define a molecular switch whereby redox-mediated posttranslational modification controls both neurogenesis and neurodegeneration via a single transcriptional signaling cascade.

A new type of output mechanism with shaking block chute type small tooth number difference is proposed,and the motion analysis of the transmission pin and the output shaft is carried out. Then through the software establishment three-dimensional model,the movement simulation analysis of the reducer is carried out.The characteristics of the output movement is studied. By changing the distance between the drive pin and the outer gear center and other parameters,the smoothness of the output movement is improved.

A new representation method of the workspace of a planar parallel manipulator is presented.Taking the 3 RRR plane parallel robot as an example,according to the iterative search method,the inverse solution equation is used as the discriminant,and the circular search of workspace is carried out. After the data processing,the three-dimensional display of the full-posture workspace of planar parallel manipulator is obtained,and its characteristics are studied. On this basis,the reachable workspace is obtained and the working space does not exist empty pole length ratio.

A circular search algorithm for solving the spatial boundary of the planar parallel robot is proposed which is based on the iterative search method,and its flexibility index is analyzed. A series of boundary points for the workspace of the 3- RRR planar robot are determined by using the circular search algorithm depending on the existence of the inverse solution of the system. The results are consistent with the results by using geometric method. The restricted,dimension consistent Jacobian matrix can be obtained by using the speed of the end effector to represent the movement of the mechanism,which can measure the flexibility of the planar parallel robot,and with help of the Matlab graphics,the new Jacobi condition number distribution in the working space is intuitively reflected. According to the obtained Jacobian matrix,the more accurate flexibility indexes can be got.

The optimal design of the straight-conjugate internal gear pair tooth profile parameter is carried out,the performance parameter functional equation of the straight-conjugate internal gear pair is analyzed.The optimization design mathematical model is set up,and the design variables are decided.By making use of the Matlab optimizing software tool,the optical calculation to the whole gear pair and he detailed comparison about the performance and tooth profile parameters of the before and after are carried out.