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The association of physical activity, heart rate and sleep from an activity tracker with weight loss during a 6-month personalized combined lifestyle intervention: a retrospective analysis
Get PDFOrganoids-on-a-chip:microfluidic technology enables culture of organoids with enhanced tissue function and potential for disease modeling
Get PDFOrganoids are stem-cell derived tissue structures mimicking specific structural and functional characteristics of human organs. Despite significant advancements in the field over the last decade, challenges like limited long-term functional culture and lack of maturation are hampering the implementation of organoids in biomedical research. Culture of organoids in microfluidic chips is being used to tackle these challenges through dynamic and precise control over the organoid microenvironment. This review highlights the significant breakthroughs that have been made in the innovative field of “organoids-on-chip,” demonstrating how these have contributed to advancing organoid models. We focus on the incorporation of organoids representative for various tissues into chips and discuss the latest findings in multi-organoids-on-chip approaches. Additionally, we examine current limitations and challenges of the field towards the development of reproducible organoids-on-chip systems. Finally, we discuss the potential of organoids-on-chip technology for both in vitro and in vivo applications.</p
Context-specific clinical applicability of the end-expiratory occlusion test to predict fluid responsiveness in mechanically ventilated patients:A systematic review and meta-analysis
Get PDFBACKGROUND The emergence of context-specific clinical evidence from the end-expiratory occlusion test (EEOT) may change the perception of its operative performance to predict fluid responsiveness. OBJECTIVE(S) Assessment of predictive performance of the EEOT in the intensive care unit (ICU) and operating room. DESIGN Systematic review of observational diagnostic test accuracy studies with meta-analysis. DATA SOURCES MEDLINE, Embase and Scopus were used as data sources for relevant publications until February 2024. ELIGIBILITY CRITERIA Prospective clinical studies in which the EEOT was used to predict fluid responsiveness in mechanically ventilated adults, regardless of the clinical care context. The operative performance characteristics must also have been reported. RESULTS Twenty-four studies involving 1073 adult patients (588 receiving intensive care and 485 in the operating room) were systematically reviewed, and 22 studies comprising 1049 volume expansions were meta-analysed. The pooled sensitivity [95% confidence interval (CI)] of the EEOT was 0.87 (0.81 to 0.92), and the pooled specificity was 0.90 (0.85 to 0.94); the median [interquartile range] cardiac index (CI) threshold for a positive test was a 5.0 [3.3 to 5.3] increase. The clinical context, the method used for haemodynamic monitoring, the ratio of the averaging time of the monitoring method to the occlusion time, the levels of positive end-expiratory pressure and the choice of cardiac output marker were identified as significant sources of heterogeneity. However, the occlusion duration and tidal volume did not significantly affect its performance. A novel insight is that performance was notably lower in the operating room setting. The likelihood ratios were 14 (positive) and 0.12 (negative) for the ICU, both better than 3.1 and 0.21 for the operating room. The overall quality of the evidence was assessed to be very low, mainly due to high heterogeneity and risk of bias; however, no publication bias was detected. CONCLUSION The EEOT for predicting fluid responsiveness in critical care performs acceptably well overall and is a confirmative test. In the operating room and/or with specific technical settings, its performance and clinical utility are reduced, driving the need for more context-specific and patient-specific fluid responsiveness assessments.</p
Microbubble-Enhanced Cold Plasma Activation (MB-CPA) for Promoting Vegetable Growth in Hydroponics
No full textIncreasing global population, climate change, environmental pollution, and rapid urbanization have dramatically increased the global food demand. Innovative technologies minimizing the use of scarce freshwater resources while still boosting crop production are highly desirable. This study introduces microbubble-enhanced cold plasma activation (MB-CPA) technology to generate plasma-activated water (PAW) and investigates its effects on plant seedling growth in hydroponic systems. Coupling of the Venturi tube helped to efficiently transfer the reactive nitrogen and oxygen species (RONS) generated by air cold plasma discharge via microbubble formation. Notably, a high and stable concentration of nitrate (NO3-; 28 mg/L) and nitrite (NO2-; 5 mg/L) was estimated in PAW. Lab-scale investigations showed that garlic seedlings treated for 15 min MB-CPA have 1.5 times longer shoots and heavier weights than those irrigated with tap water and chemically prepared N-containing (NO3- and NO2-) water. Interestingly, the treated garlic showed an almost 1.3-fold increase in sulfur content (104 mg/kg) compared to control, indicating an increase of beneficial natural sulfur compounds. Similar growth enhancements were observed in peanuts, garlic, and soybean sprouts, with PAW-treated plants showing 1.66, 1.5, and 1.8 times longer sprouts, respectively, compared to untreated groups. Application of MB-CPA to a large-scale commercial hydroponic system (108 units of garlic) demonstrated the accelerated rate of germination, improved shoot growth, and a higher root-to-shoot ratio. Furthermore, 32-day study comprising three growth cycles utilizing recycled PAW water resulted in a 1.53-fold increase in fresh weight and a 1.46-fold increase in dry weight of garlic during the final growth cycle. These findings demonstrate that MB-CPA is a promising, sustainable, and environmentally friendly fertilizing technology and can be an alternative for the improvement of agricultural production.</p
The effects of a real-time public transport information app on travel behaviour, traffic levels and the environment
No full textAdvanced Traveller Information Systems (ATIS) have been shown to improve travel satisfaction and to make public transport more attractive, but their effect on traffic, travel behaviour, and environmental externalities remains an open question. Addressing these questions is key to determining the impact of policies supporting ATIS in sustainability outputs. In this paper, we study the case of Red, a nationwide real-time public transport mobile application in Chile. Through a survey conducted on the app, we analyse the effects that the use of the app has on modal choice, public transport demand, vehicle kilometres travelled (VKT) and environmental externalities. One of the surveys questions was the counterfactual mode: we asked participants which mode they would have used in their latest trip if they did not have access to the app. Contrasting this with the revealed mode used in the latest trip, allowed us to estimate the modal substitution rate. We performed Monte Carlo simulations to estimate the Red effect on total VKT and environmental pollution. We find that: (i) when using Red, perceived waiting time decreased and personal security improved, (ii) 23.5% of the Red users changed their travel behaviour: 10.5% changed travel mode change and 13.6% chose another bus route or bus stop because of using Red (iii) urban buses gain and lose passengers (3:2 ratio, with a net increase in demand), competing mainly with shared taxis and ride-hailing, (iv) the induced demand for public transport is 1.1%, (v) the app reduces total VKT (probability P=0.99), and CO 2 emissions (88%), and (vi) variation on local air pollutant emissions depends on vehicles environmental standards, decreasing only under high standards (Euro VI). Our method was applied to the case of an ATIS app, but is suitable to analyse the sustainability effects of any policy that increases public transport demand.</p
Emergence of Imaginary Time Crystals in the non-Hermitian Su-Schrieffer-Heeger model
Get PDFParity-time symmetry constrains the spectrum of non-Hermitian systems to be either real or come in complex conjugate pairs. The transition between a symmetry-preserving phase with real energies and a symmetry-broken phase with complex energies is marked by exceptional points, one of the hallmarks of non-Hermitian systems. Because of these properties, these systems are widely studied, both theoretically and experimentally. In this work, we investigate the thermodynamic properties of the gain and loss Su-Schrieffer-Heeger model for both bosons and fermions, and establish the existence of an imaginary time crystal phase, an imaginary time analogue of a time crystal. This phase occurs when there is a resonance condition between the Matsubara frequencies and the spectrum of the system, making the Green's function of the system oscillate in imaginary time with the Matsubara frequency. We show that this phase appears in the symmetry-broken region. In particular, the topological edge states of this system exhibit oscillations that are present for bosons. Finally, we discuss the applicability of our results for experiments. We examine signatures of these phases in terms of correlation functions in real time and oscillations in thermodynamic potential in inverse temperature , and explore possible experimental platforms to realize this system
Solving dual sourcing problems with supply mode dependent failure rates
Get PDFThis paper investigates dual sourcing problems with supply mode dependent failure rates, particularly relevant in managing spare parts for downtime-critical assets. To enhance resilience, businesses increasingly adopt dual sourcing strategies using both conventional and additive manufacturing techniques. This paper explores how these strategies can optimise sourcing by addressing variations in part properties and failure rates. A significant challenge is the distinct failure characteristics of parts produced by these methods, which influence future demand. To tackle this, we propose a new iterative heuristic and several reinforcement learning techniques combined with an endogenous parameterised learning (EPL) approach. This EPL approach–compatible with any learning method–allows a single policy to handle various input parameters for multiple items. In a stylised setting, our best policy achieves an average optimality gap of 0.4%. In a case study within the energy sector, our policies outperform the baseline in 91.1% of instances, yielding average cost savings up to 22.6%.</p
Circularity assessment across construction project phases with Building Information Modelling
Get PDFTo facilitate circular design and construction practices, project stakeholders need insights into circularity across different project phases. Building information modelling (BIM) technologies provide new opportunities for developing methods to assess the circularity performance of buildings. However, most existing BIM-based circularity methods are not well-suited to handle different amounts of available information or varying Levels of Development (LOD) across project phases. This study, therefore, used a Design Science Research Methodology to develop a prototypical BIM-based circularity assessment tool. This standalone tool integrated three calculation models with a user interface to offer circularity insights based on BIM models with different LOD, covering initiative, design and construction phases. The tool's potential was validated through twelve user-based evaluation sessions and its implementation in a renovation project in the Netherlands. This study contributes to the field by introducing an innovative approach that takes information availability into account and showcases BIM's capabilities to support circularity assessments
A robust and efficient rate-independent crystal plasticity model based on successive one-dimensional solution steps
Get PDFAn efficient stress update algorithm for rate-independent crystal plasticity is presented. A series of successive one-dimensional solution (SODS) steps traces the hypersurfaces describing the slip state for which the yield criteria of individual slip systems are fulfilled to identify the intersection of all hypersurfaces. This provides both the active set and all slip components without requiring iterative active set search procedures or inducing spurious slip on inactive systems. The basic SODS algorithm is accelerated by tracking the evolution of the active set. A fast Newton–Raphson procedure enables to obtain the solution for an unchanging active set directly, while line search and extrapolation procedures direct the SODS steps towards the solution faster. A regularised tangent modulus is proposed that eliminates stiffness jumps upon changes in active set to improve the convergence behaviour of outer (equilibrium) iterations conducted with the algorithm. The resulting stress update algorithm is highly stable and efficient, making it an attractive candidate for use in large-scale crystal plasticity FE simulations and homogenisation algorithms.</p
Empirical motion-artifact reduction for non-rigid motion in dedicated breast CT
No full textObjective. The goal of this work is to develop a data-driven empirical motion-artifact reduction algorithm for non-rigid motion in dedicated breast CT. Methods. Breast CT is a novel imaging modality that offers fully 3D images at good spatial resolution without breast compression and tissue overlap. However, the slow rotation speed of the gantry in such systems increases the likelihood of motion artifacts. Because of the breast anatomy, motionartifact reduction techniques need to be able to handle artifacts induced by non-rigid motion, which cannot be modeled due to variable motion patterns and the breasts' inner structure, shape, and size. In this work, we present an iterative data-driven empirical algorithm to reduce motion artifacts in breast CT. The highlight of our method is the ability to perform transformations in the image domain using b-spline fields that are defined for each angle and can be efficiently updated with gradient descent and automatic differentiation. Result. We test the method using a simulation study, on physical phantoms, and clinical cases, and show that it can significantly reduce the appearance of motion artifacts. Conclusion and Significance. This work introduces a fully data-driven empirical motion-artifact reduction capable of identifying and minimizing motion artifacts without an underlying model of motion.</p