Mechanistic Link Research Articles

Optomechanics and Sensing Phenomena: An Analysis in Classical-quantum Relationship

As a multi-approach sensing field optomechanics is primarily related to the interaction between optical and mechanical modes interaction. Light-matters dealings in linear to non-linear routes are trails of precision and Quantum Sensing (QS). Light is a wave-matter quantum entity from the classical Electromagnetic (EM) field in which matter is entangled with waves in space-time dimension. The interaction of electromagnetic radiation with the motion of objects and the gravity action is an energy perturbation and complex phenomenon. The energy-mass relation is like wave matter in which a possible link between classical and quantum mechanics is imperative for advanced opto-mechanical sensing. The quantization of mechanical energy and its interaction with light is a process that can be used for diverse sensing purposes. In this study light and gravity-related electromagnetic and mechanical system linkage has been elucidated systematically at macro and micro levels for optomechanical sensing system further development.

Bacterial amyloid curli activates the host unfolded protein response via IRE1α in the presence of HLA-B27

ABSTRACT Salmonella enterica serovar Typhimurium (STm) causes gastroenteritis and can progress to reactive arthritis (ReA). STm forms biofilms in the gut that secrete the amyloid curli, which we previously demonstrated can trigger autoimmunity in mice. HLA-B27 is a genetic risk factor for ReA; activation of the unfolded protein response (UPR) due to HLA-B27 misfolding is thought to play a critical role in ReA pathogenesis. To determine whether curli exacerbates HLA-B27-induced UPR, bone marrow-derived macrophages (BMDMs) isolated from HLA-B27 transgenic (tg) mice were used. BMDMs treated with purified curli exhibited elevated UPR compared to C57BL/6, and curli-induced IL-6 was reduced by pre-treating macrophages with inhibitors of the IRE1α branch of the UPR. In BMDMs, intracellular curli colocalized with GRP78, a regulator of the UPR. In vivo, acute infection with wild-type STm increased UPR markers in the ceca of HLA-B27tg mice compared to C57BL/6. STm biofilms that contain curli were visible in the lumen of cecal tissue sections. Furthermore, curli was associated with macrophages in the lamina propria, colocalizing with GRP78. Together, these results suggest that UPR plays a role in the curli-induced inflammatory response, especially in the presence of HLA-B27, a possible mechanistic link between STm infection and genetic susceptibility to ReA.

Characterization of Friction within a Novel 3 mm Wristed Robotic Instrument

Surgical robotic tools are being developed for a variety of surgical procedures that are executed within small workspaces. Novel designs of miniaturized cable-actuated surgical tools for cleft palate repair have previously been developed. However, the behavior and significance of friction within these tools are largely unknown. A study was conducted to investigate the friction in a pulleyless 3 mm diameter wristed instrument. The wrist utilizes cable guide channels that allow for miniaturization at the cost of increased friction. An experimental rig was developed to measure friction within the wrist link mechanism when the tool is positioned at various pitch angles. A strong relationship between the cable tension and the tool’s pitch angle was found as a result of friction. The cable tension increased as the pitch angle approached extreme values (percent increases in the cable tension of 33% and 67.3% at a pitch of 90° and −90°, respectively). However, the resultant cable tension was below the failure strength of the cable, indicating that the design is feasible. The results of this study would be useful to those considering the design of miniature robotic surgical tools that are cable-driven. Significant tool reduction can be achieved by employing static guide channels for the cables, forgoing the use of additional moving components like pulleys while maintaining cable tension well within its break strength. Future work in the design and optimization of novel miniaturized wrist mechanisms should consider frictional effects and their impact on mechanism function.

KCNJ16-depleted kidney organoids recapitulate tubulopathy and lipid recovery upon statins treatment

BackgroundThe KCNJ16 gene has been associated with a novel kidney tubulopathy phenotype, viz. disturbed acid–base homeostasis, hypokalemia and altered renal salt transport. KCNJ16 encodes for Kir5.1, which together with Kir4.1 constitutes a potassium channel located at kidney tubular cell basolateral membranes. Preclinical studies provided mechanistic links between Kir5.1 and tubulopathy, however, the disease pathology remains poorly understood. Here, we aimed at generating and characterizing a novel advanced in vitro human kidney model that recapitulates the disease phenotype to investigate further the pathophysiological mechanisms underlying the tubulopathy and potential therapeutic interventions.MethodsWe used CRISPR/Cas9 to generate KCNJ16 mutant (KCNJ16+/− and KCNJ16−/−) cell lines from healthy human induced pluripotent stem cells (iPSC) KCNJ16 control (KCNJ16WT). The iPSCs were differentiated following an optimized protocol into kidney organoids in an air–liquid interface.ResultsKCNJ16-depleted kidney organoids showed transcriptomic and potential functional impairment of key voltage-dependent electrolyte and water-balance transporters. We observed cysts formation, lipid droplet accumulation and fibrosis upon Kir5.1 function loss. Furthermore, a large scale, glutamine tracer flux metabolomics analysis demonstrated that KCNJ16−/− organoids display TCA cycle and lipid metabolism impairments. Drug screening revealed that treatment with statins, particularly the combination of simvastatin and C75, prevented lipid droplet accumulation and collagen-I deposition in KCNJ16−/− kidney organoids.ConclusionsMature kidney organoids represent a relevant in vitro model for investigating the function of Kir5.1. We discovered novel molecular targets for this genetic tubulopathy and identified statins as a potential therapeutic strategy for KCNJ16 defects in the kidney.

Identifying mechanistic links between sleep disturbance and binge eating: the role of depressed mood

ABSTRACT Global sleep disturbance is robustly linked with a subjective sense of loss-of-control over eating (LOC). Depressed mood has been proposed as a mechanism to explain the bi-directional relationship between sleep disturbance and LOC eating. The current study evaluated whether sleep disturbance indirectly affects LOC eating via depressed mood. Adults seeking treatment for a DSM-5 binge-spectrum eating disorder (e.g. bulimia nervosa, binge-eating disorder) were recruited (n = 79) and asked to complete self-report questionnaires assessing sleep disturbance and depression, and a semi-structured interview assessing LOC eating. Tests of indirect effects evaluated the effect of depressed mood on the association between global sleep disturbance and LOC frequency covarying for BMI and parent study. A significant indirect effect of depressed mood on the association between global sleep disturbance and frequency of LOC eating was identified (Est = 1.519, S.E. = 0.859, p = .033). The indirect effect of depressed mood on the association between sleep disturbance and LOC eating may indicate that depressed mood serves as a mechanistic link between sleep disturbance and LOC eating. The findings offer preliminary support for adjunctive treatments targeting both sleep disturbance and depressed mood for LOC eating. Future research should explore these pathways in a larger clinical sample.

Research on the "2+1" Talent Training Model in Higher Vocational Railway Colleges under the "Four Platforms and One Meeting" Linkage Mechanism

This study aims to explore the construction and implementation of the "2+1" talent training model in higher vocational railway colleges under the "Four Platforms and One Meeting" linkage mechanism. Through theories of school-enterprise cooperation, Internet+ education, and talent training models, the study analyzes the construction methods of school-enterprise teaching platforms, online resource platforms, enterprise practice platforms, and school-enterprise joint "2+1" teaching feedback platforms. The research finds that the "Four Platforms and One Meeting" linkage mechanism can effectively integrate school and enterprise resources, leverage the advantages of Internet+, improve the quality of talent training, and provide innovative pathways for the reform of higher vocational education.

Deep Learning Conceptual Design of Sit-to-Stand Parallel Motion Six-Bar Mechanisms

Abstract The sit-to-stand (STS) motion is a crucial activity in the daily lives of individuals, and its impairment can significantly impact independence and mobility, particularly among disabled individuals. Addressing this challenge necessitates the design of mobility assist devices that can simultaneously satisfy multiple conflicting constraints. The effective design of such devices often involves the generation of numerous conceptual mechanism designs. This paper introduces an innovative single-degree-of-freedom (DOF) mechanism synthesis process for developing a highly customizable sit-to-stand (STS) mechanical device by integrating rigid body kinematics with machine learning. Unlike traditional mechanism synthesis approaches that primarily focus on limited functional requirements, such as path or motion generation, our proposed design pipeline efficiently generates a large number of 1DOF mechanism geometries and their corresponding motion paths, known as coupler curves. Leveraging a generative deep neural network, we establish a probabilistic distribution of coupler curves and their mapping to mechanism parameters. Additionally, we introduce novel metrics for quantitatively evaluating and prioritizing design concepts. The methodology yields a diverse set of viable conceptual design solutions that adhere to the specified constraints. We showcase various single-degree-of-freedom six-bar linkage mechanisms designed for STS motion, presenting them in a ranked order based on established criteria. While the primary focus is on the integration of STS motion into a versatile mobility assist device, the proposed approach holds broad applicability for addressing design challenges in various applications.

Research on Modelling of Strategic Linkage Mechanism Between Urban and Rural Logistics System and New Development Pattern in the Era of Big Data

Research on Modelling of Strategic Linkage Mechanism Between Urban and Rural Logistics System and New Development Pattern in the Era of Big Data

Temporal Immune Profiling in the CSF and Blood of Patients with Aneurysmal Subarachnoid Hemorrhage.

Delayed cerebral ischemia (DCI) is a significant complication of aneurysmal subarachnoid hemorrhage (aSAH). This study profiled immune responses after aSAH and evaluated their association with DCI onset. Twelve aSAH patients were enrolled. Leukocyte populations and cytokine levels were analyzed in cerebrospinal fluid (CSF) and peripheral blood (PB) on days 3, 5, 7, 10, and 14 post-aSAH. Peripheral blood mononuclear cells (PBMCs) were collected and their cytokine production quantified following stimulation. Mixed-effects models revealed distinct immune cell dynamics in CSF compared to blood. Natural killer T cell frequency increased over time in CSF only, while monocyte/macrophage numbers increased in both CSF and PBMCs. CD4+ HLA II+ T cells increased in circulation. Unstimulated PBMCs showed increased IL-1β, IL-6, and TNFα production, peaking at 7 days post-aSAH, coinciding with typical DCI onset. Ex vivo stimulation of PBMCs showed that only IL-6 significantly changed over time. In CSF, cytokines peaked 5 days post-injury, preceding immune cell profile alterations. Our findings reveal a time-dependent immune response following aSAH, with distinct within-patient patterns in CSF and PB. The early CSF cytokine peak preceding immune cell changes suggests a potential mechanistic link and identifies the cytokine response as a promising therapeutic target. This cytokine surge may drive immune cell expansion and prime PBMCs for increased inflammatory activity, potentially contributing to DCI risk. Future studies should explore the importance and sources of specific cytokines in driving immune activation. These insights may inform the development of targeted immunomodulatory strategies for preventing or managing DCI in aSAH patients.

The unfolded protein response regulates ER exit sites via SNRPB-dependent RNA splicing and contributes to bone development.

Splicing and endoplasmic reticulum (ER)-proteostasis are two key processes that ultimately regulate the functional proteins that are produced by a cell. However, the extent to which these processes interact remains poorly understood. Here, we identify SNRPB and other components of the Sm-ring, as targets of the unfolded protein response and novel regulators of export from the ER. Mechanistically, The Sm-ring regulates the splicing of components of the ER export machinery, including Sec16A, a component of ER exit sites. Loss of function of SNRPB is causally linked to cerebro-costo-mandibular syndrome (CCMS), a genetic disease characterized by bone defects. We show that heterozygous deletion of SNRPB in mice resulted in bone defects reminiscent of CCMS and that knockdown of SNRPB delays the trafficking of type-I collagen. Silencing SNRPB inhibited osteogenesis in vitro, which could be rescued by overexpression of Sec16A. This rescue indicates that the role of SNRPB in osteogenesis is linked to its effects on ER-export. Finally, we show that SNRPB is a target for the unfolded protein response, which supports a mechanistic link between the spliceosome and ER-proteostasis. Our work highlights components of the Sm-ring as a novel node in the proteostasis network, shedding light on CCMS pathophysiology.

Myosin forces elicit an F-actin structural landscape that mediates mechanosensitive protein recognition.

Cells mechanically interface with their surroundings through cytoskeleton-linked adhesions, allowing them to sense physical cues that instruct development and drive diseases such as cancer. Contractile forces generated by myosin motor proteins mediate these mechanical signal transduction processes through unclear protein structural mechanisms. Here, we show that myosin forces elicit structural changes in actin filaments (F-actin) that modulate binding by the mechanosensitive adhesion protein α-catenin. Using correlative cryo-fluorescence microscopy and cryo-electron tomography, we identify F-actin featuring domains of nanoscale oscillating curvature at cytoskeleton-adhesion interfaces enriched in zyxin, a marker of actin-myosin generated traction forces. We next introduce a reconstitution system for visualizing F-actin in the presence of myosin forces with cryo-electron microscopy, which reveals morphologically similar superhelical F-actin spirals. In simulations, transient forces mimicking tugging and release of filaments by motors produce spirals, supporting a mechanistic link to myosin's ATPase mechanochemical cycle. Three-dimensional reconstruction of spirals uncovers extensive asymmetric remodeling of F-actin's helical lattice. This is recognized by α-catenin, which cooperatively binds along individual strands, preferentially engaging interfaces featuring extended inter-subunit distances while simultaneously suppressing rotational deviations to regularize the lattice. Collectively, we find that myosin forces can deform F-actin, generating a conformational landscape that is detected and reciprocally modulated by a mechanosensitive protein, providing a direct structural glimpse at active force transduction through the cytoskeleton.

Interdependence between myocardial deformation and perfusion in patients with T2DM and HFpEF: a feature-tracking and stress perfusion CMR study

BackgroundPatients with diabetes have an increased risk of developing heart failure with preserved ejection fraction (HFpEF). This study aimed to compare indices of myocardial deformation and perfusion between patients with type 2 diabetes mellitus (T2DM) with and without HFpEF and to investigate the relationship between myocardial strain and perfusion reserve.MethodsThis study included 156 patients with T2DM without obstructive coronary artery disease (CAD) and 50 healthy volunteers who underwent cardiac magnetic resonance (CMR) examination at our center. Patients with T2DM were subdivided into the T2DM–HFpEF (n = 74) and the T2DM–non-HFpEF (n = 82) groups. The parameters of left ventricular (LV) and left atrial (LA) strain as well as stress myocardial perfusion were compared. The correlation between myocardial deformation and perfusion parameters was also assessed. Mediation analyses were used to evaluate the direct and indirect effects of T2DM on LA strain.ResultsPatients with T2DM and HFpEF had reduced LV radial peak systolic strain rate (PSSR), LV circumferential peak diastolic strain rate (PDSR), LA reservoir strain, global myocardial perfusion reserve index (MPRI), and increased LA booster strain compared to patients with T2DM without HFpEF (all P < 0.05). Furthermore, LV longitudinal PSSR, LA reservoir, and LA conduit strain were notably impaired in patients with T2DM without HFpEF compared to controls (all P < 0.05), but LV torsion, LV radial PSSR, and LA booster strain compensated for these alterations (all P < 0.05). Multivariate linear regression analysis demonstrated that LA reservoir and LA booster strain were independently associated with global MPRI (β = 0.259, P < 0.001; β = − 0.326, P < 0.001, respectively). Further, the difference in LA reservoir and LA booster strain between patients with T2DM with and without HFpEF was totally mediated by global MPRI. Global stress PI, LA booster, global rest PI, and global MPRI showed high accuracy in diagnosing HFpEF among patients with T2DM (areas under the curve [AUC]: 0.803, 0.790, 0.740, 0.740, respectively).ConclusionsPatients with T2DM and HFpEF exhibited significant LV systolic and diastolic deformation, decreased LA reservoir strain, severe impairment of myocardial perfusion, and elevated LA booster strain that is a compensatory response in HFpEF. Global MPRI was identified as an independent influencing factor on LA reservoir and LA booster strain. The difference in LA reservoir and LA booster strain between patients with T2DM with and without HFpEF was totally mediated by global MPRI, suggesting a possible mechanistic link between microcirculation impairment and cardiac dysfunction in diabetes. Myocardial perfusion and LA strain may prove valuable for diagnosing and managing HFpEF in the future.

The anti-gender movement and the populist radical right in Italy: a symbiotic relationship

The political landscape of Italy experienced a seismic shift in the September 2022 elections, marking a watershed moment. Giorgia Meloni, the leader of the populist radical right party (PRRP) Brothers of Italy, was elected as Italy’s head of government. This event highlighted a significant development in the country’s gender politics, reflecting the ascent of PRRPs across Europe, marked by their reactionary politics, emphasis on traditional values and staunch opposition to gender equality. This study focuses on the dynamics between PRRPs (Brothers of Italy and the League) and the anti-gender movement in Italy. Through a qualitative content analysis of the primary sources of political parties and movements, the research explores their symbiotic relationship, the linkage and adjustment mechanisms employed by both actors, and the political outcomes of their interactions, offering insights into the mobilization of anti-gender actors and their alliance with PRRPs. It contributes to understanding how the organized opposition to gender equality is mainstreamed within political spheres, especially in contexts where right-wing populists hold power.

Modulation of NOX2 causes obesity-mediated atrial fibrillation.

Obesity is linked to an increased risk of atrial fibrillation (AF) via increased oxidative stress. While NADPH oxidase 2 (NOX2), a major source of oxidative stress and reactive oxygen species (ROS) in the heart, predisposes to AF, the underlying mechanisms remain unclear. Here, we studied NOX2-mediated ROS production in obesity-mediated AF using Nox2-knockout mice and mature human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCMs). Diet-induced obesity (DIO) mice and hiPSC-aCMs treated with palmitic acid (PA) were infused with a NOX blocker (apocynin) and a NOX2-specific inhibitor, respectively. We showed that NOX2 inhibition normalized atrial action potential duration and abrogated obesity-mediated ion channel remodeling with reduced AF burden. Unbiased transcriptomics analysis revealed that NOX2 mediates atrial remodeling in obesity-mediated AF in DIO mice, PA-treated hiPSC-aCMs, and human atrial tissue from obese individuals by upregulation of paired-like homeodomain transcription factor 2 (PITX2). Furthermore, hiPSC-aCMs treated with hydrogen peroxide, a NOX2 surrogate, displayed increased PITX2 expression, establishing a mechanistic link between increased NOX2-mediated ROS production and modulation of PITX2. Our findings offer insights into possible mechanisms through which obesity triggers AF and support NOX2 inhibition as a potential novel prophylactic or adjunctive therapy for patients with obesity-mediated AF.

Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum

BACKGROUND Colorectal polyps, which are characterized by a high recurrence rate, represent preneoplastic conditions of the intestine. Due to unclear mechanisms of pathogenesis, first-line therapies for non-hereditary recurrent colorectal polyps are limited to endoscopic resection. Although recent studies suggest a mechanistic link between intestinal dysbiosis and polyps, the exact compositions and roles of bacteria in the mucosa around the lesions, rather than feces, remain unsettled. AIM To clarify the composition and diversity of bacteria in the mucosa surrounding or 10 cm distal to recurrent intestinal polyps. METHODS Mucosal samples were collected from four patients consistently with adenomatous polyps (Ade), seven consistently with non-Ade (Pol), ten with current Pol but previous Ade, and six healthy individuals, and bacterial patterns were evaluated by 16S rDNA sequencing. Linear discriminant analysis and Student’s t -tests were used to identify the genus-level bacteria differences between groups with different colorectal polyp phenotypes. Pearson’s correlation coefficients were used to evaluate the correlation between intestinal bacteria at the genus level and clinical indicators. RESULTS The results confirmed a decreased level of probiotics and an enrichment of pathogenic bacteria in patients with all types of polyps compared to healthy individuals. These changes were not restricted to the mucosa within 0.5 cm adjacent to the polyps, but also existed in histologically normal tissue 10 cm distal from the lesions. Significant differences in bacterial diversity were observed in the mucosa from individuals with normal conditions, Pol, and Ade. Increased abundance of Gram-negative bacteria, including Klebsiella , Plesiomonas , and Cronobacter , was observed in Pol group and Ade group, suggesting that resistance to antibiotics may be one risk factor for bacterium-related harmful environment. Meanwhile, age and gender were linked to bacteria changes, indicating the potential involvement of sex hormones. CONCLUSION These preliminary results support intestinal dysbiosis as an important risk factor for recurrent polyps, especially adenoma. Targeting specific pathogenic bacteria may attenuate the recurrence of polyps.

Investigating correlation effects of uncertain input variables in reliability-oriented sensitivity analysis for planar linkage mechanism

Investigating correlation effects of uncertain input variables in reliability-oriented sensitivity analysis for planar linkage mechanism

The applicability of a SIF-based mechanistic model for estimating GPP at the canopy scale

Mechanistically linking gross primary productivity (GPP) and sun-induced chlorophyll fluorescence (SIF) is an essential step to unleash the full potential of SIF for remote sensing-based predictions of GPP across biomes, climates, and spatiotemporal scales. The latest SIF-based mechanistic light response model that includes the fraction of open photosystem II reaction centers as key parameter (qMLR-SIF model), can accurately reproduce leaf-scale photosynthesis under various conditions. However, it remains unclear to what extent the qMLR-SIF model is suitable for estimating GPP at larger scales such as the canopy scale. Therefore, canopy-scale data of tower-based far-red SIF, GPP and key environmental variables from 10 study sites were collected to analyze the SIF-GPP relationship and to compare the qMLR-SIF model with the widely used Farquhar, von Caemmerer, Berry (FvCB) model and with a light use efficiency (LUE) model for different plant functional types (PFTs), photosynthetic pathways (C3 and C4), and temporal scales (hourly, daily and 4-day). Results showed that the nonlinear SIF-GPP relationship existed in all PFTs and the degree of linearity increased at larger temporal scales. The qMLR-SIF model exhibited wide applicability to quantify canopy GPP for different PFTs (R2 = 0.55–0.80, RMSE = 2.72–11.03 μmol CO2 m-2 s-1), photosynthetic pathways (R2 = 0.70–0.78, RMSE = 5.29–9.05 μmol CO2 m-2 s-1) and temporal scales (R2 = 0.82–0.97, RMSE = 3.42–8.32 μmol CO2 m-2s-1). Compared with the two other models, the qMLR-SIF model performed best overall, which is mainly due to its simpler model structure and the mechanistic link between SIF and photosynthesis. Particularly, the qMLR-SIF model could more accurately estimate GPP in C4 species, with higher R2 (0.78) and lower RMSE (8.46 μmol CO2 m-2s-1). These findings highlight the advantages of the qMLR-SIF model in GPP estimation at the canopy scale, showing its potential in applications at regional and global scales.

Linked Links—A Research Project: The Multiple Superimposed Soft Networks as Network Profiles

This article, based on network science, aims to contribute to overcoming its geometric and technological phases. The novelty consists in considering links of networks as linked by superimposed networks, termed here multiple superimposed soft networks (MSSN), which is introduced as a research issue. Such links of links (termed here as passive links) concern, for instance, correspondences, incompatibilities, and temporal synchronizations between the occurrences of pairs of active links of effective networks, such as those based on electrical and telecommunication. A possible constitutive mechanism of such passive linkage consists of linkage representations for practices and histories of use expressed by their validating statistical reoccurrences. We consider the possible emergent nature of the passive linkage. The reason for introducing the design and usage of MSSN properties as a research issue involves making new approaches to profile and manage networks available. Correspondence between active linkage and MSSN properties should be a matter for an experiential, machine-learning approach. Research issues relate their possible usage on the active linkage such as for classification, comparations, detection of criticalities, diagnosis, performance evaluation, and regulatory as weak forces. Furthermore, the possible identification of standard corresponding configurations of passive and active linkage is finalized to avoid their establishment or, conversely, in facilitating their establishment and keeping their replication in different contexts (or partially and in combinations) and identifying related standardized approaches (also for classes of configurations having significant levels of equivalence). This research project has methodological generalizing aspects of trans-disciplinarity. We conclude by mentioning related research issues.

Research on engine dynamic torque modeling for torsional vibration analysis of vehicle powertrain

In order to improve the accuracy of dynamic torque model of engine, a simulation model of quasi-transient engine dynamic torque under all operating conditions was established considering the influence of throttle opening. Firstly, the calculation model of engine output torque and cylinder pressure is established according to the kinematic relation of crank linkage mechanism. Secondly, BP neural network is used to establish the mapping relationship model of throttle opening, rotational speed, and cylinder pressure ratio data. In order to solve the contradiction between calculation accuracy and efficiency of engine cylinder pressure interpolation, a quadratic interpolation method is proposed, which refines data to improve interpolation accuracy, and improves calculation efficiency by online adjacent interpolation, and completes the construction of dynamic torque simulation model of engine in all working conditions. Finally, the experimental data of dynamic torque characteristics of the engine at different speeds are used to verify the accuracy of the model calculation. By using the verified engine model, the dynamic operating characteristics of variable valve opening and variable speed are simulated and analyzed. The results show that the model established in this paper can effectively reflect the dynamic characteristics of the engine, and the model is suitable for the simulation of the torsional vibration of the vehicle powertrain under steady and unsteady conditions.

A novel reconfigurable UAV design and control based on the parallel linkage

To enhance the maneuverability of unmanned aerial vehicles (UAVs) in confined spaces, this paper proposes a novel reconfigurable multi-rotor UAV. The UAV uses servos to drive its arms and thus change its configuration, enabling it to alter its morphology like a bird, reduces the largest dimension of the vehicle by approximately 41%↑. The body is connected to the motor base through a linkage mechanism, allowing synchronized movement between the arm and the motor. This synchronization helps the UAV to reduce the loss of thrust suffered after morphology transformation. This paper analyzes and deduces the changes in physical characteristic parameters during the process of UAV reconfiguration. It combines the active disturbance rejection control with the backstepping-based super-twisted sliding mode control to design a cascade control strategy that suppresses the disturbance caused by the UAV reconfiguration on flight control. The simulation and physical flight experiments demonstrate that the UAV is capable of reconfiguring into multiple morphologies during flight while maintaining flight stability throughout the reconfiguration process.