Mechanical Work Research Articles

The contractile efficiency of the mantle muscle of European common cuttlefish (Sepia officinalis) during cyclical contractions.

Escape jet propulsion swimming in cuttlefish (Sepia officinalis) is powered by the circular muscles surrounding the mantle cavity. This mode of locomotion is energetically costly compared with undulatory swimming. The energetic cost of swimming is determined by the mechanical power requirements and the efficiency with which chemical energy is transferred into useful mechanical work. One step in this energy transduction process is the transfer of energy from ATP hydrolysis into mechanical work by the muscles. Here, we determined the efficiency of this step, termed the contractile efficiency. Muscle preparations from the circular muscles of the mantle cavity were subjected to sinusoidal length changes at different cycle frequencies, and stimulated with a phase and duration that maximised initial net work. Changes in ATP, arginine phosphate and octopine content between control and exercised muscles were determined and used to calculate the energy released from ATP hydrolysis (Emet). The maximum contractile efficiency (the ratio of net work to Emet) was 0.37, occurring at the same cycle frequency at which mechanical power was maximal and that was used during jet propulsion swimming, suggesting that cuttlefish muscle is adapted to generate muscular power efficiently. The overall efficiency of cuttlefish jet propulsion swimming was estimated to be 0.17, which is broadly comparable to that measured during animal flight and human-powered pedalled locomotion, indicating the high energetic costs of jet propulsion swimming are not due to inefficient locomotion per se; instead, they result from the relatively high mechanical power requirements.

Prototyping disruptive self-sufficiency power machines composed by cascaded power units based on thermo-hydraulic actuators

This research focuses on developing a prototype for a disruptive Self-Sustaining Power Machine (SSPM) that consists of cascaded power units (PUs). Each PU integrates thermo-mechanical and thermo-hydraulic actuators to drive hydraulic pumps connected to generators. The prototype's design leverages two thermal cycle types, sVsVs and VsVs, which enable self-sustaining operations by employing several strategic capabilities that challenge the limitations of second-kind perpetual motion machines (PMMs). Therefore, key capabilities include: 1- Performing useful mechanical work through the expansion and contraction of the Thermal Working Fluid (TWF) by adding and removing heat. 2- Utilizing recovered heat through potential superposition techniques, thereby upgrading the heat to a higher grade, which enhances heat recovery strategies. 3- Designing an efficient energy transfer chain from thermal to electrical energy via thermo-mechanical or thermo-hydraulic actuators, a hydraulic energy drive system, and conversion from hydraulic to electrical energy. 4- Configuring the system to achieve more useful work than the heat added to the initial PU downstream. Two main prototype types are proposed to demonstrate these proposed capabilities: 1- Continuous motion using the sVsVs thermal cycle, with volumetric reservoirs for thermal working fluids (TWF) located outside the thermo-mechanical or thermo-hydraulic actuators. 2- Discontinuous motion using the VsVs thermal cycle, with volumetric reservoirs for TWF located inside the active volume of the thermo-mechanical or thermo-hydraulic actuators. The prototypes were evaluated through case studies using air and helium as real TWFs. Results indicate that the SSPM composed of five cascaded PUs operating on an sVsVs cycle achieved a global efficiency of 149.6% (SSI of 49.6%) with helium and 126% (SSI of 26%) with air. In contrast, the VsVs cycle yielded a global efficiency of 183% (SSI of 83%) with helium and 133% (SSI of 33%) with air

External Mechanical Work Versus Energy Expenditure During on-Court Tennis Drills in Elite Adolescent Tennis Players

Abstract Purpose Tennis demands exceptional technical skills, speed, strength and endurance. Previous studies have highlighted the high energy expenditure during tennis drills due to constant directional changes. While metabolic monitoring and player tracking have been used to quantify exercise intensity and movements, mechanical efficiency (ME) in tennis remains poorly understood. This study aimed to investigate ME in tennis by combining metabolic and mechanical measurements during on-court drills. Methods Ten elite adolescent tennis players (males n = 5, females n = 5) performed a VO2max test on a treadmill and participated in three standard tennis drills, Spanish cross, lateral and inside out. During the tennis drill, full-body kinematics were captured, and energy expenditure was measured using a portable breath-by-breath gas analysis. ME was calculated for each drill, and individual differences were examined. Results Results revealed significant differences in energy expenditure and mechanical work between drills. ME was not associated with VO2max or running speed. highlighting the need to focus on other factors like strength, footwork technique, and neuromuscular training to enhance ME. Conclusion This study underscores the complexity of ME in tennis, with individual variations and where factors like footwork technique, muscular strength and motor abilities might influence ME.

Decent work and work fulfilment: The mediating role of work engagement and the moderating role of psychological ownership

This study explores the well-being (engagement) and work fulfilment of 628 blue-collar workers as outcomes of decent work, based on the Psychology of Working Theory and its target group. It takes a positive preventative approach and demonstrates the motivational role of work engagement and psychological ownership in contributing to the work fulfilment of blue-collar workers experiencing decent work. Data was collected from a South African-owned trailer manufacturing company. The results show a positive relationship between decent work and work fulfilment, with work engagement mediating this relationship. Additionally, psychological ownership positively moderates the relationship between decent work and work engagement. This study adds insights into the underlying mechanism (work engagement) that elucidates how decent work relates to work fulfilment. This study sheds light on how decent work contributes to work fulfilment through work engagement. Furthermore, suggesting that this relationship is stronger for blue-collar workers with higher levels of psychological ownership.

Relationship of professional identity and efficacy of Chinese public university lecturers under the appointment system in sustainable human resource management

For Chinese university lecturers, implementing sustainable human resource management (SHRM) is particularly critical. China's higher education is going through an essential stage of appointment system reform aiming to overturn the traditional civil service status of university lecturers and introduce a more flexible work and talent management mechanism to universities to international teaching standards; lecturers also raise concerns about their professional role, educational mission, balance of rights and interests, and the reshaping of the evaluation system. Based on the resource-based perspective and psychological contract theory, this study aimed to explore the relationship between sustainable human resource management (SHRM) and lecturers' professional identity in the context of China's appointment system, focusing on analyzing the moderating role of lecturers' self-efficacy. This study used a quantitative research approach to collect survey data from 610 lecturers at public colleges and universities in China. The data were analyzed with a structural equation model to test the hypothesized relationships. SHRM was directly and positively related to lecturers' self-efficacy and sense of professional identity and indirectly improved sense of professional identity by enhancing self-efficacy. The findings are consistent with existing literature, emphasize the importance of SHRM in promoting lecturers' career development, and provide empirical support for applying SHRM in the context of Chinese higher education. The study provides recommendations in three dimensions: Government, University, and Faculty. It provides guidance for strategic reform of human resource management in higher education, faculty career development, and improving education quality.

Combination of integrated machine learning model frameworks and infrared spectroscopy towards fast and interpretable characterization of model pyrolysis oil

Model pyrolysis oil (bio-oil) is a promising bio-fuel with complex and unstable contents, making its fast characterization an essential demand in industrial production. This study proposed an integrated machine learning framework to predict elemental composition, low heating value, and unsaturated concentration from infrared spectra, achieving fast and interpretable characterization of bio-oil. In the integrated framework, a peak loading-based strategy was used to dimensionally reduce the spectral data. Bayesian optimized random forest (RF) and extreme gradient boosting (XGBoost) models were used to predict bio-oil properties from dimensionally reduced spectral data. Ensemble learning was used to combine RF and XGBoost models together for better predicting performance. Results showed that the proposed characterization method achieved an average accuracy of 99.53 %, a low RMSE value of 0.726, and an R2 of 0.98. The Shapley value analysis revealed that the vibration of NH2 stretch (1594 cm−1), C-H stretch (2868 cm−1), and C-N stretch in the aromatic ring (1229 cm−1) have a significant contribution to the characterization results. The working mechanism of the proposed characterization method was interpreted by the internal relationship among spectral peak location/height, functional group species/amount, and the predicted characteristics. The results are hoped to serve quality control in production of bio-oil.

Development of high-quality and water-resistant PBG through H-PDMS modification: From experiments to molecular dynamics simulation

The effective treatment and high-value application of phosphogypsum (PG) are of critical importance for the sustainable development of this construction material. However, its poor water-resistance property has limited its application in the construction field. In order to expand the application potential of phosphorous-building gypsum (PBG) as a durable material, potassium hydroxide (KOH) and hydroxyl‑terminated polydimethylsiloxane (H-PDMS) were used as the activating agent, and the water-resistant modifying agent in this study, respectively, to develop a high-quality and water-resistant PBG product. In addition, molecular dynamics was used to reveal the modification mechanism of H-PDMS and the water-resistance mechanism of KOH activating PBG. The study results show that H-PDMS can significantly improve the water-resistance performance of PBG test blocks. KOH can increase the surface activity of PBG by introducing -OH radicals, promote the reaction between H-PDMS and PBG, and form a dense hydrophobic layer on PBG, thus effectively improving its water-resistance performance. The number of surface active -OH radicals in PBG, the clustering effect of H-PDMS, and impurities in PBG can all result in different experimental and simulation outcomes. Meanwhile, the electrostatic force is an important factor influencing the adsorption of water droplets on the surface of PBG, and the reaction of H-PDMS with PBG normally occurs between Si-O and S-O. This study has systematically interpreted the working mechanism of water-resistant PBG, presenting an important significance in the utilization of PG resources.

Coherence resonance in a memristive map neuron and adaptive energy regulation

Involvement of memristive term and additive physical variables including magnetic flux and charge can enhance the physical description of the biophysical neurons. Neural circuits coupled with memristors can be built and tamed to mimic the intrinsic biophysical characteristics and dynamical properties of biological neurons, and these memristive oscillator models are effective in predicting the mode transition in neural activities and self-organization in collective electric behaviors of neural networks. Any proposal of memristive map neurons requires reliable physical description. For example, the energy definition and self-adaptive working mechanism are crucial to verify the reliability of memristive maps. A capacitive variable is useful to describe the membrane potential, while the complexity of ion channels requires careful evaluation and description by using inductive variables relative to the electromagnetic field. In this work, a charge-controlled memristor is connected to an inductor in series for building a hybrid ion channel, and then a capacitor and a nonlinear resistor are combined to couple the ion channel. As a result, a simple memristive neural circuit is designed to discern the inner effect of electric field and magnetic field synchronously. The energy function is defined and verified with theoretical proof. Furthermore, a linear transformation is applied to convert this memristive neuron into a memristive map with an exact energy description, in which its dynamics and mode transition will be controlled by an adaptive law when its energy is beyond the threshold. Additive noise is imposed to induce coherence resonance, which can be detected by using the statistical analysis and average value for Hamilton energy function during changes in noise intensity. This scheme provides guidance for energy definition in memristive maps and the intrinsic energy regulation mechanism in neural activities is explained from physical and dynamical aspects.

Flexible carbon-coated paper electrokinetic generator with Schottky-junction

Simulating transpiration effect to harvest electricity has attracted continued interest. However, it is limited to directional water/ions transport that shrinks the application scenario. Herein, we propose a new carbon-coated paper electrokinetic generator with Schottky-junction to induce the electricity. The electrical double layer (EDL) forms at carbon-water interface due to the wetting paper that induces an obvious electrical sign. The introduce of Schottky-junction inhibits the carrier recombination that enhances the charge separation. As a result, the output performance is significantly improved. Besides, it breakthroughs the limitation of directional water/ions transport to realize multi-mode energy harvesting due to joint working mechanisms of EDL and Schottky-junction. Consequently, the electrical sign is still remained in the case of full wetting rather than disappearance, showing great potential in practical applications. As a demonstration, it can judge the condition of simulated pipe through the feedback of electrical signal, charges the capacitors to energy storage and powers digital calculator, et al. The cheap and flexible paper-based generators offer a new path to clean energy harvesting and sensor applications.

Influence of a single osteopathic procedure on the regulatory processes of the body of premature infants (pilot study)

Introduction. The number of children born early in gestation and with low body weight and associated health disorders require the search for effective methods of rehabilitation treatment. The development of new effective non-invasive methods of rehabilitation/rehabilitation of premature infants is one of the priority tasks of national health care.Aims — to evaluate the effect of a single osteopathic procedure on the regulatory processes of the body (an indicator of the activity of regulatory systems and an index of nervous system tension) in premature infants.Materials and methods. In the clinic 30 premature infants with a gestation period of 24 to 37 weeks were monitored on the terms of voluntary written informed consent (the average gestation period was 31,35±0,45 weeks). The children were aged from 2 to 12 months (the average age was 4,93±0,45 months), of which 53,3 % (16 people) were boys and 46,6 % (14 people) were girls. On admission, parents most often complained about sleep disorders: sleep is not long, the child often wakes up at night or cries in his sleep, often sleeps only in the arms of his mother. It is difficult to feed the child, he does not eat the daily norm of food. During wakefulness, the child is restless, and when crying, calms down only in the arms. Osteopathic examination and correction were performed according to the clinical recommendations «Somatic Dysfunctions» and patent № 2739128 «Method of treatment of pain syndrome on the background of somatic dysfunctions in newborns». The procedures are carried out, as a rule, in the first half of the day, lasting 20 minutes. A methodical technique in the form of a single osteopathic procedure was used, when first the patient is examined, immediately after that the procedure and again the examination. The state of nervous system tension was assessed using cardiointervalography, the index of activity of the body′s regulatory systems and the index of tension of the autonomic nervous system were evaluated. The FLACC-SS pain assessment scale for infants, which we modified, was used to assess pain. Psychomotor development was assessed using the Griffiths developmental scale. The Statistica-10 software package was used for statistical analysis of the obtained data.Results. Upon admission, the pain level on the FLACC-SS scale was 2,35±1,35 points, which indicates, on average, moderate pain intensity in children. The Griffiths score was 31,64±3,57 points, which indicates a delay in psychomotor development in children. In the study of CIG before osteopathic correction, the IN was 597,77±89,99 units, and the PARS was 5,10±0,85 points. This is a pronounced functional stress of the body and is characterized by a decrease in its functional reserves and an inadequate response to environmental factors. During the initial osteopathic examination, somatic dysfunctions were detected mainly at the global level (changes in skeletal muscle tone, changes in cranial, cardiac and respiratory rhythms). After a single osteopathic correction procedure, the tension index decreased statistically significantly, and there was also a tendency to decrease the level of tension of regulatory systems. The pain level in children decreased to 0,16 points, which means.Conclusion. Somatic dysfunctions play an important role in the development of disorders of body regulation and pain syndrome. Correction of somatic dysfunctions in premature infants by osteopathy methods helps to reduce pain syndrome and improve the adaptive mechanisms of the body. Thus helps to prevent energy-consuming increased work of regulatory mechanisms, to adjust sleep and wakefulness, to improve appetite and, ultimately, the quality of life of the infant and the whole family. Restoring the energy balance of the child′s body, optimizing the work of regulatory systems, reducing the intensity of pain syndrome makes it possible to start early rehabilitation of premature infants.

Dynamic simulation and optimal design of a combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration

A combined cold and power system with 10 MW compressed air energy storage and integrated refrigeration (CCR) is proposed. In traditional 10 MW compressed air energy storage (CAES) system, outlet pressure of air tank is throttled to a low pressure by throttling device. In CCR system, the throttling device is replaced by a piston turbine to achieve control of pressure and mass flow. Meanwhile, pressure potential energy of compressed air is converted to mechanical work, which is used to drive refrigeration subsystem. The dynamic mathematic model of proposed CCR system is built up. According to energy and exergy analysis of the whole dynamic process, it is confirmed that the proposed model obeys the first and second laws of thermodynamics. The optimal solution for T23 and γAC are calculated to be 259.6896 K and 1.2335, respectively. The Pareto frontier of multi-objective optimization of energy and exergy efficiencies are conducted. Energy efficiency of proposed CCR system is higher than that of CAES system by at least 32.8 %. The electrical efficiency of proposed CCR system is also higher than that of CAES system. It suggests that the pressure potential energy wasted in the throttle process is well utilized by the piston turbine in CCR system.

A real‐time cognitive map construction method based on the entorhinal‐hippocampal working mechanism of the rat's brain

A real‐time cognitive map construction method based on the entorhinal‐hippocampal working mechanism of the rat's brain

Exploring the transcriptional cooperation between RUNX2 and its associated elncRNA RAIN

Recent insights into the mechanisms controlling gene expression identified enhancer-associated long non-coding RNAs (elncRNAs) as master players of transcription in cancers. RUNX2, a mammalian RUNT-related transcription factor, is increasingly recognized in cancer biology for its role in supporting survival and progression also in thyroid cancer (TC). We recently identified, within the RUNX2 locus, a novel elncRNA that we named RAIN (RUNX2 associated intergenic lncRNA). We showed that RAIN and RUNX2 expression correlate in TC, both in vitro and in vivo, and that RAIN promotes RUNX2 expression by interacting with and affecting the activity of the RUNX2 P2 promoter through two distinct mechanisms. Here, we took forward these observations to explore the genome-wide transcriptional function of RAIN and its contribution to the RUNX2-dependent gene expression program in TC. By combining multiple omics data, we demonstrated that RAIN functionally cooperates with RUNX2 to the regulation of a subset of functionally related genes involved in promoting matrix remodeling, migration, and loss of differentiation. We showed that RAIN interacts with RUNX2 and its expression is required for the efficient recruitment of this TF to its target regulatory regions. In addition, our data revealed that besides RUNX2, RAIN governs a hierarchically organized complex transcriptional program by controlling a core of cancer-associated TFs that, in turn, orchestrate the expression of downstream genes. This evidence indicates that the functional cooperation observed between RAIN and RUNX2 can be a diffuse work mechanism for this elncRNA.

Dinitrophenyl and NBD platforms based fluorescent sensors for nanomolar detection of zinc ions: Synthesis, zinc ions sensing and DFT studies

The design and synthesis of two new fluorescent probes based on dinitrophenyl (1) and 7-nitrobenz-2-oxa-1,3-diazole (2) platforms is reported. Both probes, containing bis(pyridin-2-ylmethyl)amine as a receptor unit can efficiently detect zin ions (Zn2+) in aqueous solution, with limit of detections of 124 nM and 1.06 µM, respectively. Probe 1 and 2 led to 3-fold and 2.4-fold fluorescent enhancements, respectively, with the addition of Zn2+ which suggested that working mechanism of these probes is based on the inhibition of the photoinduced electron transfer from the electron donating receptor towards the excited fluorophore. Studying binding stoichiometry by job’s plot suggested 1:1 complexation between the probe and Zn2+. Moreover, the formation of probes-Zn2+ complexes was validated by both FT-IR and 1H NMR wherein marked changes in the absorption frequencies as well as distinct downfield shifts in the resonance peaks of pyridine function along with the CH2 group linked directly to the tertiary nitrogen of the DPA unit were observed. Density functional theory (DFT) calculations suggested that the electronic density of the HOMO in 1 was concentrated on the linker between DPA and dinitrophenyl, whereas the density of the LUMO was concentrated on dinitrophenyl moiety. Upon Zn2+ binding, the electronic density in HOMO and LUMO become more delocalized. However, in case of probe 2 the delocalization of electronic density does not appreciably occur. Based on DFT simulations, both sensors form thermodynamic stable complexes with Zn2+ ions. However, sensor 2 exhibited slightly better binding preference toward Zn2+ as compared to 1. The PET based probes exhibited good selectivity to detect Zn2+ in the presence of a variety of competing metal cations. These sensors have higher sensitivity and would be able to detect chronic level of Zn2+ in the freshwater (>1.84 μM) as permitted by the US EPA.

Research on the application and prospects of variable reluctance inductive sensors

Variable reluctance inductive sensors are extensively utilized in the industrial field due to its unique working mechanism and good performance characteristics. Based on the working principle of Variable Reluctance Inductive Sensors, this paper reviews its development history, application in industrial automation and medical industry. Through the analysis of variable reluctance inductive sensors, variable reluctance inductive sensors have the advantages of high sensitivity, low cost and reliability which can support its wide application in precision measurement, position detection and motion control, but it is susceptible to the interference of the external magnetic field and the influence of the temperature which limits its development space and scope. However, the advancement of new materials, intelligent technologies and multi-mode integration has broadened the potential of future development of sensors and created more challenges for the development of variable reluctance inductive sensors. The update of new research conditions also provides a valuable reference of research and application in related fields

Opening the Black Box: The Underlying Working Mechanisms in Virtual-Reality Exposure Therapy for Anxiety Disorders

Although research on virtual-reality (VR) exposure therapy (VRET) in anxiety disorders has primarily focused on effectiveness and acceptability, the underlying working mechanisms have received scant attention. To fill this knowledge gap, we discuss potential theoretical underpinnings of VRET based on three dominant theoretical accounts on exposure: inhibitory-learning theory (expectancy violation), emotional-processing theory (habituation), and self-efficacy theory. Whereas theoretically speaking, habituation and self-efficacy seem plausible candidate mechanisms to explain the effects of VRET, the role of expectancy violation is less straightforward. Because of the simulated nature of VR, some feared outcomes cannot occur, and therefore, possibilities to violate expectancies about their occurrence may be compromised. Empirical evidence on the working mechanisms of VRET is scarce and has important limitations. Avenues for future research are provided. Insights into the mechanisms of VRET not only are of theoretical importance but also can provide theory-based directions to optimize the application of VRET.

Protective role of TRPM7 knockdown in ulcerative colitis via blocking NLRP3 inflammasome-mediated pyroptosis

Transient receptor potential melastatin 7 (TRPM7) has been emerged as a potent drug target for immunomodulation with ion conductance and kinase activities. The research is projected to characterize the influences of TRPM7 on the course of ulcerative colitis (UC) and dissect the latent response mechanisms. The in vivo murine model and in vitro cell model of UC were both stimulated by DSS. RT-qPCR and western blotting tested the abundance of TRPM7. Colonic damage was estimated by Hematoxylin-eosin staining, calculation of colon length, measurement of DAI and MPO assay kit. CCK-8 method and TUNEL staining severally ascertained cell activity and apoptosis. ELISA method assayed the inflammatory levels and relevant assay kits determined oxidative stress levels. FITC-dextran flux, immunohistochemistry, TEER as well as western blotting evaluated intestinal barrier function. Immunofluorescence staining and western blotting appraised NLR family pyrin domain containing 3 (NLRP3)-dependent pyroptosis. Depleted TRPM7 retarded inflammation, oxidative damage as well as intestinal barrier damage both in vitro and in vivo. TRPM7 reduction repressed the pyroptosis mediated by NLRP3 inflammasome. NLRP3 agonist nigericin partly abolished the protection elicited by TRPM7 silencing against inflammation, oxidative damage as well as intestinal barrier damage in vitro. Collectively, TRPM7 deletion might possess the therapeutic potential in UC, the working mechanism of which might involve the inactivation of NLRP3-dependent pyroptosis.

Enhancing the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 by surface modification with homemade high-purity hexagonal phase tungsten oxide nanoparticles

Nickel-rich layered oxides with high energy density and acceptable cost are considered as one of the most ideal cathode materials for power batteries. However, its large-scale production and application still face the challenge in terms of rapid capacity fading and poor structural stability, which has prompted research into surface coating materials/technologies within both academic and industrial fields. In this work, A feasible and environmental friendly fabrication method of high-purity hexagonal phase tungsten oxide (h-WO3) nanoparticles as surface modification of LiNi0.8Co0.1Mn0.1O2(NCM) is proposed.The results indicate that NCM modified with h-WO3 has lower Li+/Ni2+ mixing rate, superior rate performance, and better cycling stability than the pristine NCM. Although tungsten oxide is widely used as surface modification due to its excellent physical and chemical properties, but its crystal type has not been considered, and there is little research on the theoretical explanation of h-WO3 modification.This work reveals the working mechanism of h-WO3 from the perspective of interface and crystal type, which can provide meaningful reference for obtaining nickel-rich layered oxides with excellent electrochemical properties.

Unveiling the Terahertz Nano-Fingerprint Spectrum of Single Artificial Metallic Resonator.

As artificially engineered subwavelength periodic structures, terahertz (THz) metasurface devices exhibit an equivalent dielectric constant and dispersion relation akin to those of natural materials with specific THz absorption peaks, describable using the Lorentz model. Traditional verification methods typically involve testing structural arrays using reflected and transmitted optical paths. However, directly detecting the dielectric constant of individual units has remained a significant challenge. In this study, we employed a THz time-domain spectrometer-based scattering-type scanning near-field optical microscope (THz-TDS s-SNOM) to investigate the near-field nanoscale spectrum and resonant mode distribution of a single-metal double-gap split-ring resonator (DSRR) and rectangular antenna. The findings reveal that they exhibit a dispersion relation similar to that of natural materials in specific polarization directions, indicating that units of THz metasurface can be analogous to those of molecular structures in materials. This microscopic analysis of the dispersion relation of artificial structures offers new insights into the working mechanisms of THz metasurfaces.

Uncovering the key working mechanisms of a complex community-based obesity prevention programme in the Netherlands using ripple effects mapping

BackgroundMuch remains unknown about how complex community-based programmes can successfully achieve long-term impact. More insight is needed to understand the key mechanisms through which these programmes work. Therefore, we conducted an in-depth study in five communities that implemented the Healthy Youth, Healthy Future (JOGG) approach, a Dutch community-based obesity prevention programme. We aimed to identify perceived outcomes and long-term impacts among local stakeholders and explore potential causal pathways and working mechanisms.MethodsWe used ripple effects mapping (REM), a qualitative participatory method to map outcomes and identify causal pathways, in five communities. We involved 26 stakeholders, professionals and policy-makers affiliated with the local JOGG approach, spread over eight REM sessions and conducted individual interviews with 24 additional stakeholders. To uncover working mechanisms, we compared outcomes and causal pathways across communities.ResultsOver 5–9 years of implementation, participants perceived that JOGG had improved ownership of local stakeholders, health policies, intersectoral collaboration and social norms towards promoting healthy lifestyles. Causal pathways comprised small initial outcomes that created the preconditions to enable the achievement of long-term impact. Although exact JOGG actions varied widely between communities, we identified five common working mechanisms through which the JOGG approach contributed to causal pathways: (1) creating a positive connotation with JOGG, (2) mobilizing stakeholders to participate in the JOGG approach, (3) facilitating projects to promote knowledge and awareness among stakeholders while creating successful experiences with promoting healthy lifestyles, (4) connecting stakeholders, thereby stimulating intersectoral collaboration and (5) sharing stakeholder successes that promote healthy lifestyles, which gradually created a social norm of participation.ConclusionsThe JOGG approach seems to work through activating initial stakeholder participation and bolstering the process towards ownership, policy change, and intersectoral collaboration to promote healthy lifestyles. Key working mechanisms can inform further development of JOGG as well as other complex community-based prevention programmes.