A general design method of cam profile based on cubic splines and dynamic model : case study of a gravity-driven tricycle

This paper proposes a general design method for cams based on the kinematics and dynamics of a mechanical system. According to the actuator’s trajectory, the cam profile is generated in reverse based on the kinematic model of the system. Firstly, the cam design’s optimising problem is converted into the execution trajectory’s optimisation to obtain the optimum operation trajectory according to the actuator’s requirements. Secondly, the relationship between the cam profile and the actuation trajectory is modelled based on the kinematics and dynamics of the mechanical system. Then, applying the cubic spline interpolation method, the cam profile is generated, and the error compensation methods are illustrated through numerical analysis. Finally, the validity of the presented design method is verified through experiments, which demonstrate the reliability of this method

The Long Noncoding RNA MALAT1 Induces Tolerogenic Dendritic Cells and Regulatory T Cells via miR155/Dendritic Cell-Specific Intercellular Adhesion Molecule-3 Grabbing Nonintegrin/IL10 Axis

By shaping T cell immunity, tolerogenic dendritic cells (tDCs) play critical roles in the induction of immune tolerance after transplantation. However, the role of long noncoding RNAs (lncRNAs) in the function and immune tolerance of dendritic cells (DCs) is largely unknown. Here, we found that the lncRNA MALAT1 is upregulated in the infiltrating cells of tolerized mice with cardiac allografts and activated DCs. Functionally, MALAT1 overexpression favored a switch in DCs toward a tolerant phenotype. Mechanistically, ectopic MALAT1 promoted dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) expression by functioning as an miR155 sponge, which is essential for the tolerogenic maintenance of DCs and the DC-SIGN-positive subset with more potent tolerogenic ability. The adoptive transfer of MALAT1-overexpressing DCs promoted cardiac allograft survival and protected from the development of experimental autoimmune myocarditis, accompanied with increasing antigen-specific regulatory T cells. Therefore, overexpressed MALAT1 induces tDCs and immune tolerance in heart transplantation and autoimmune disease by the miRNA-155/DC-SIGH/IL10 axis. This study highlights that the lncRNA MALAT1 is a novel tolerance regulator in immunity that has important implications in settings in which tDCs are preferred

Administration of Interleukin-35-Conditioned Autologous Tolerogenic Dendritic Cells Prolong Allograft Survival After Heart Transplantation

Background/Aims: IL-35, a powerful suppressor of inflammation and autoimmunity, is primarily secreted by regulatory T cells (Tregs) and can, in turn, promote Treg differentiation. However, the precise effect of IL-35 on dendritic cells (DCs) remains to be clarified. Methods: In this study, we investigated the expression of IL-35 in DCs after stimulation with LPS utilizing enzyme linked immunosorbent assay(ELISA), quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) and western blotting, and the influence of IL-35 on the maturation and function of DCs by mixed lymphocyte reaction assay and flow cytometry. We further examined the regulation of IL-35 in DCs by the microRNA let-7i (let-7i) via transfected with let-7i mimic, inhibitor or suppressor of cytokine signalling 1 (SOCS1) siRNA. IL-35-overexpressing DCs were transfused into BALB/c recipients with C57BL/6 heart transplantations to verify the role of immune tolerance in transplantation. Results: The results showed that IL-35 expression was significantly up-regulated following lipopolysaccharide (LPS)-induced DC maturation. Overexpression of IL-35 suppressed DC maturation, promoted the secretion of anti-inflammatory cytokines, and subsequently affected the balance between Treg and Th17 cells. IL-35 expression in DCs was regulated by let-7i, which targets SOCS1. The transfusion of IL-35-transfected DCs induced Treg generation in mice and prolonged cardiac allograft survival. Conclusion: Our data demonstrated that IL-35 induces tolerogenic DCs which are capable of alleviating allograft rejection. Clinical application of IL-35-treated DCs might be a promising approach for eliciting cardiac allograft immune tolerance

Field measurement of the erosion threshold of silty seabed in the intertidal flat of the Yellow River Delta with a newly-developed annular flume

Accurately measuring the critical shear stress is crucial for numerous applications, such as sediment transport modeling, erosion prediction, and the design of sustainable coastal engineering structures. However, developing reliable and precise in-situ measurement devices faces significant challenges due to the harsh and dynamic nature of aquatic environments. Factors like turbulence and waves introduce complexities that must be considered when designing and calibrating these devices. The newly developed Openable Underwater Carousel In-situ Flume (OUC-IF) was used to determine the critical shear stress (τc) and quantify erosion rates. Acoustic Doppler Velocimeter (ADV) was employed to measure 3D near-bottom velocities, which were then used to estimate and pre-calibrate bed shear stress (τ) applied on the seabed in the annular flume. Three computation methods of shear stress were evaluated: turbulent kinetic energy (TKE), direct covariance (COV), and log profile (LP). In-situ erosion experiments were conducted for the first time at two sites in the tidal flat of the Yellow River Delta (site 1 with a water depth of 1.32 m and site 2 with a water depth of 0.75 m). The critical shear stress was found to be 0.10 Pa at site 1 and 0.19 Pa at site 2, and the erosion rates of the sediments were successfully measured. The effect of wave-seabed interactions on erosion resistance was explored by theoretically estimating the wave-induced pore pressure of the seabed based on the observed data. The max liquefaction degree of the seabed at site 1 and site 2 was 0.035 and 0.057, respectively, and the average erosion coefficient Me was 2.63E-05 kg m-2s-1 at site 1 and 3.48E-05 kg m-2s-1 at site 2

Deciphering a mitochondria-related signature to supervise prognosis and immunotherapy in hepatocellular carcinoma

BackgroundHepatocellular carcinoma (HCC) is a major public health problem in humans. The imbalance of mitochondrial function has been discovered to be closely related to the development of cancer recently. However, the role of mitochondrial-related genes in HCC remains unclear.MethodsThe RNA-sequencing profiles and patient information of 365 samples were derived from the Cancer Genome Atlas (TCGA) dataset. The mitochondria-related prognostic model was established by univariate Cox regression analysis and LASSO Cox regression analysis. We further determined the differences in immunity and drug sensitivity between low- and high-risk groups. Validation data were obtained from the International Cancer Genome Consortium (ICGC) dataset of patients with HCC. The protein and mRNA expression of six mitochondria-related genes in tissues and cell lines was verified by immunohistochemistry and qRT-PCR.ResultsThe six mitochondria-related gene signature was constructed for better prognosis forecasting and immunity, based on which patients were divided into high-risk and low-risk groups. The ROC curve, nomogram, and calibration curve exhibited admirable clinical predictive performance of the model. The risk score was associated with clinicopathological characteristics and proved to be an independent prognostic factor in patients with HCC. The above results were verified in the ICGC validation cohort. Compared with normal tissues and cell lines, the protein and mRNA expression of six mitochondria-related genes was upregulated in HCC tissues and cell lines.ConclusionThe signature could be an independent factor that supervises the immunotherapy response of HCC patients and possess vital guidance value for clinical diagnosis and treatment

Identification of m6a-related signature genes in esophageal squamous cell carcinoma by machine learning method

Background: We aimed to construct and validate the esophageal squamous cell carcinoma (ESCC)-related m6A regulators by means of machine leaning.Methods: We used ESCC RNA-seq data of 66 pairs of ESCC from West China Hospital of Sichuan University and the transcriptome data extracted from The Cancer Genome Atlas (TCGA)-ESCA database to find out the ESCC-related m6A regulators, during which, two machine learning approaches: RF (Random Forest) and SVM (Support Vector Machine) were employed to construct the model of ESCC-related m6A regulators. Calibration curves, clinical decision curves, and clinical impact curves (CIC) were used to evaluate the predictive ability and best-effort ability of the model. Finally, western blot and immunohistochemistry staining were used to assess the expression of prognostic ESCC-related m6A regulators.Results: 2 m6A regulators (YTHDF1 and HNRNPC) were found to be significantly increased in ESCC tissues after screening out through RF machine learning methods from our RNA-seq data and TCGA-ESCA database, respectively, and overlapping the results of the two clusters. A prognostic signature, consisting of YTHDF1 and HNRNPC, was constructed based on our RNA-seq data and validated on TCGA-ESCA database, which can serve as an independent prognostic predictor. Experimental validation including the western and immunohistochemistry staining were further successfully confirmed the results of bioinformatics analysis.Conclusion: We constructed prognostic ESCC-related m6A regulators and validated the model in clinical ESCC cohort as well as in ESCC tissues, which provides reasonable evidence and valuable resources for prognostic stratification and the study of potential targets for ESCC

Effect of HAc on the Metastable Pitting Corrosion of 304 SS in NaCl Solution

Stainless steels (SSs) easily suffer localized corrosion damage, such as pitting corrosion, in mixed solutions of acetic acid and sodium chloride. Currently, few works have been focused on the early stages of the pitting corrosion (metastable pitting corrosion) process of SSs in a chloride-HAc mixture solution. In this work, the effects of acetic acid (HAc) and its concentration on metastable pitting corrosion and the uniform corrosion of 304 SS in 0.6 mol/L NaCl solution were investigated by a slow-scanning potentiodynamic polarization test, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results show that the uniform corrosion rate of 304 SS increases after HAc addition but, with an increase in HAc concentration, the corrosion rate decreases. In the presence of HAc, the metastable pitting potential (Em) and stable pitting potential (Eb) move negatively, but the number of metastable pits notably decreases. HAc has a promoting action on the growth rate of the metastable pits and facilitates the transition from metastable pits to stable pits. The influence of HAc is related to a decrease in solution pH and the chemical adsorption of HAc

Modélisation, simulation et optimisation de récupérateurs d'énergie cinétique miniatures avec tribo-électrets

Harvesting energy from the ambient environment is a good sustainable and complementary power supply solution in some consumer electronics, distributed wireless sensor networks, wearable or implantable devices, "Internet of Things" systems with lots of nodes, etc. in comparison with batteries. The ubiquitous kinetic energy in various motions and vibrations is one of the most available energy sources for such a purpose. The electret kinetic energy harvesters (E-KEHs) is one type of electrostatic kinetic energy harvesters using electrets (dielectrics with quasi-permanent charges) as the biasing voltage source, which can generate electricity based on the electrostatic induction effect when the capacitance of the E-KEHs is changed by the motions/vibrations. This thesis aims to investigate the transitory output characteristics of E-KEHs by both theoretical simulations and experimental measurements and to optimize the efficiency and output power of E-KEHs by tribo-charging and other methods adapted to their output characteristics, which are significant to improving the performance of E-KEHs.Firstly, the amplitude-variable output characteristics of a contact-separation (CS) mode E-KEH in transitory working cycles are investigated via the simulation results based on a detailed equivalent circuit model. These amplitude-variable output characteristics are attributed to the lag of the charge-transfer cycle behind the excitation motion cycle. The influences of both the initial condition and the load resistance on the variation in the output voltage peaks of a tribo-electret KEH (TE-KEH) are studied in detail and verified by both simulated and experimental data of a CS mode TE-KEH made with polytetrafluoroethylene (PTFE) electret film.Secondly, based on the analysis of the amplitude-variable output characteristics, a contact time optimization method is used to improve the output power and efficiency of the CS mode TE-KEH with a large load resistance of 100 MΩ. The theoretical maximum output energy per working cycle of the TE-KEH is analyzed. Several usually unfavorable factors that would reduce the practical output energy per working cycle of the TE-KEH are discussed. The maximum air gap optimization and the tribo-charging methods are also used together to further improve the average output power of the 4 cm × 4 cm sized TE-KEH from ~150 μW to ~503 μW.Thirdly, an innovative and facile tape-peeling tribo-charging method is developed to charge the fluorinated ethylene propylene (FEP) polymer film to make electrets without using any high voltage source. The surface potential distribution of the FEP film is apparently changed after several tape-peeling tribo-charging treatments. Consequently, the output voltage and current of TE-KEHs made with the FEP film are greatly improved. For a 64 cm2 sized flexible TE-KEH to harvest kinetic energy from wind, an apparent ~692% improvement in the output power from ~2.5 μW to ~19.8 μW was obtained by the tape-peeling charging method.La récupération d'énergie dans l'environnement ambiant est une bonne solution d'alimentation durable et complémentaire dans certains produits électroniques grand public, réseaux de capteurs distribués sans fil, dispositifs portables ou implantables, systèmes "Internet of Things" avec beaucoup de nœuds, etc. par rapport aux batteries. Les mouvements et les vibrations sont des sources d’énergie les plus disponibles à cet effet. Les dispositifs collectant de l’énergie cinétique à petite échelle sont appelés récupérateurs d'énergie cinétique (RECs). Les RECs avec électrets (E-RECs) sont un type de RECs électrostatiques qui utilisent des électrets (diélectriques avec charges quasi permanentes) comme source de tension de polarisation, et qui peuvent générer de l'électricité grâce à l'effet d'induction électrostatique lorsque la la capacitance des E-RECs varie du fait des mouvements/vibrations. Cette thèse vise à étudier les caractéristiques de sortie transitoires des E-RECs à la fois par des simulations théoriques et des mesures expérimentales, et à optimiser l’efficacité et la puissance de sortie des E-RECs par charge triboélectrique et par d'autres méthodes adaptées à leurs caractéristiques de sortie, qui sont essentielles pour améliorer la performance des E-RECs par mouvements/vibrations.Tout d'abord, les caractéristiques de sortie à amplitude variable d'un E-REC en mode contact-séparation (CS) dans des cycles de travail transitoires sont examinées via les résultats de la simulation basés sur un modèle de circuit équivalent détaillé. Ces caractéristiques de sortie à amplitude variable sont attribuées au décalage du cycle de transfert de charge par rapport au cycle de mouvement d'excitation. Les influences de la condition initiale et de la résistance de charge sur la variation des pics de tension de sortie d'un tribo-électret REC (TE-REC) en mode CS réalisé avec un film électret en polytétrafluoroéthylène (PTFE) one été étudiées en détail et vérifiées à la fois par simulations et expériences.Deuxièmement, une méthode d'optimisation du temps de contact est utilisée pour améliorer la puissance de sortie et l'efficacité du TE-REC en mode CS avec une résistance de charge de 100 MΩ. L'énergie convertie théorique maximale par cycle de travail du TE-REC est analysée. Nous avons aussi étudié les influences de plusieurs facteurs défavorables qui généralement réduiraient la conversion d'énergie par cycle de travail du TE-REC. L’optimisation de l'intervalle d'air maximal et la méthode tribo-charge sont également utilisées pour améliorer la puissance moyenne sortie du TE- REC avec une surface de 4 cm × 4 cm, de ~ 150 μW à ~ 503 μW.Troisièmement, une méthode innovante et facile a été développée pour charger le film polymère électret en éthylène propylène fluoré (FEP) par pelage de ruban adhésif, sans utiliser de source de haute tension électrique. La distribution du potentiel de la surface du film de FEP est fortement modifiée après plusieurs pelages au ruban adhésif. Par conséquence, la tension et le courant de sortie des TE-REC fabriqués avec le film FEP traités sont beaucoup améliorés. Pour un TE-REC flexible d’une surface de 64 cm2 soufflé par du vent, une amélioration évidente d'environ 692% de la puissance de sortie, correspondant 2,5 μW à environ 19,8 μW, a été obtenue par cette méthode