Search Results (116)

Intelligent reflecting surfaces (IRSs) have attracted extensive attention in the design of future communication networks. However, their large number of reflecting elements still results in non-negligible power consumption and hardware costs. To address this issue, we previously proposed a green heterogeneous IRS (HE-IRS) consisting of both dynamically tunable elements (DTEs) and statically tunable elements (STEs). Compared to conventional IRSs with only DTEs, the unique DTE–STE integrated structure introduces new challenges in optimizing the positions and phase shifts of the two types of elements. In this paper, we investigate the element position and phase shift optimization problems in HE-IRS-assisted millimeter-wave systems. We first propose a particle swarm optimization algorithm to determine the specific positions of the DTEs and STEs. Then, by decomposing the phase shift optimization of the two types of elements into two subproblems, we utilize the manifold optimization method to optimize the phase shifts of the STEs, followed by deriving a closed-form solution for those of the DTEs. Furthermore, we propose a low-complexity phase shift optimization algorithm for both DTEs and STEs based on the Cauchy–Schwarz bound. The simulation results show that with the tailored element position and phase shift optimization algorithms, the HE-IRS can achieve a competitive performance compared to that of the conventional IRS, but with much lower power consumption. Full article

Background: Olanzapine (Ola) is a second-generation antipsychotic with clinical utility limited by poor brain bioavailability due to blood–brain barrier restriction, hepatic first-pass metabolism, and systemic side effects. This study aimed to develop and optimize a novel intranasal polymersome-based nanocarrier (Poly_Ola) to enhance brain targeting, therapeutic efficacy, and safety of Ola. Methods: Poly_Ola was prepared using poloxamer 401 and optimized through a Box–Behnken Design to minimize particle size and maximize entrapment (EE%) and loading efficiency (LE%). The formulation was characterized by size, morphology, drug release, and serum stability. In vivo studies in adult male Sprague-Dawley rats assessed pharmacokinetics (plasma and brain concentrations), pharmacodynamic efficacy in a ketamine-induced schizophrenia model, and systemic safety markers including metabolic, hepatic, and testicular oxidative stress indicators. Results: Optimized Poly_Ola exhibited a particle size of 78.3 ± 4.5 nm, high EE% (91.36 ± 3.55%), and sustained in vitro drug release. It remained stable in serum for 24 h. Intranasal administration significantly improved brain delivery of Ola, achieving a 2.7-fold increase in C_max and a 5.7-fold increase in AUC compared to oral dosing. The brain T_max was 15 min, with high drug-targeting efficiency (DTE% = 365.38%), confirming efficient nose-to-brain transport. Poly_Ola-treated rats showed superior antipsychotic performance, reduced extrapyramidal symptoms, and improved systemic safety evidenced by mitigated weight gain, glycemic control, normalized liver enzymes, and reduced oxidative stress. Conclusions: Poly_Ola offers a safe and effective intranasal delivery platform for Ola, enabling targeted brain delivery and improved management of schizophrenia with reduced peripheral toxicity. Full article

Global tourism activities have become increasingly digitalized, yet the economic and environmental impacts of digitalization on tourism remain underexplored. This study develops a supply-side analytical framework to examine whether and how digitalization decouples tourism economy from carbon emissions by integrating Ghosh input-output analysis, subsystem analysis, and structural decomposition analysis. Our findings reveal that digitalization has largely decoupled China’s tourism economy from carbon emissions, with the increases in economic gains notably outpacing those in emission losses. Specifically, the digital-enabled tourism value-added (DTV) increased by approximately 18 times from 2002 to 2017, while digital-enabled tourism emissions (DTE) only grew by about 11 times. Between 2017 and 2020, due to the impact of the COVID-19 pandemic, the DTV decreased by about 61%, and DTE dropped by approximately 63.5%. The expansion in DTV can be primarily attributed to advancements in software and IT services and electronic components, while the increase in DTE is significantly driven by software and IT services and communication services. The growth in digital supply emerged as the predominant driver for the surging DTV and DTE, with the emission intensity of tourism subsectors acting as a notable constraint. This study offers both a methodological framework and empirical evidence aimed at guiding policy initiatives that target the digitalization and low-carbon transition of the tourism sector. Full article

Background and Clinical Significance: Uterine fibroids affect up to 25% of women of reproductive age and can lead to significant symptoms or impact fertility, often requiring surgical management. While hysteroscopic myomectomy is suitable for intracavitary fibroids, intramural and subserosal fibroids typically necessitate open or minimally invasive surgery (MIS). Laparoscopic approaches offer notable advantages, including reduced postoperative pain and faster recovery. However, MIS is frequently avoided in cases of very large fibroids due to technical difficulty and concerns about safe tissue extraction. Power morcellation, previously used for specimen removal, has fallen out of favor due to the risk of disseminating occult malignancies, especially in women over 35. Therefore, establishing the feasibility of MIS without morcellation in such cases is essential. Case Presentation: A woman of reproductive age presented with a symptomatic uterine fibroid measuring approximately 4 kg (1500 cm³). Laparoscopic myomectomy was performed using a modified trocar entry technique and contained tissue fragmentation, avoiding morcellation. The operation was completed successfully without complications. Postoperative recovery was uneventful, and the patient was discharged on postoperative day two. Histopathological examination confirmed a benign leiomyoma. Conclusions: This case highlights the feasibility of laparoscopic removal of an exceptionally large uterine fibroid without morcellation. Through careful patient selection, strategic trocar placement, and controlled tissue fragmentation, MIS can be safely performed in select high-volume cases. These findings support reconsidering the size limitations of laparoscopic myomectomy when conducted by experienced surgeons using appropriate techniques. Full article

To investigate the mechanisms of unexpected failures in a multi-stage gear transmission system under a relatively low load, a rigid–flexible coupled multi-body dynamics model with 10 spur gears and 12 helical gears is established. The dynamic condensation theory is applied to improve computational efficiency. The construction of this model incorporates critical nonlinear factors, ensuring high precision and reliability. Based on the proposed model, four critical dynamic parameters, including acceleration, mesh stiffness, dynamic transmission error, and vibration displacement, are analyzed. This research systematically reveals the nonlinear dynamic mechanism under the multi-gear coupling effect. The spectrum of the gears exhibits prominent low-frequency peaks at 320 Hz and 750 Hz. Notably, alternate load-dominated gears show a shift in prominent low-frequency peaks. The phenomenon of marked oscillations in mesh stiffness suggests a potential risk of localized weakening in the system’s load-carrying capacity. Critically, alternating torques induce periodic double-tooth contact regions in the gear at specific time points (0.115 s and 0.137 s), which are identified as critical factors leading to gear transmission system failures. The variation characteristics of the dynamic transmission error (DTE) demonstrate that the DTE is strongly correlated with the meshing state. The analysis of vibration displacement further indicates that the alternating external loads are the dominant excitation source of vibrations, noise, and failures in the gear transmission system. Full article

The gear-transmission system plays a crucial role in power transmission for urban railway vehicles. However, it can experience abnormal meshing conditions due to wheel polygonization, which presents a potential safety hazard for vehicle operations. To address this issue, the present study develops a dynamic model of an urban railway vehicle that integrates the gear-transmission system, simulating the effects of wheel polygonization on its dynamic behavior. The simulation results reveal that as the amplitude of wheel polygonization and vehicle speed increase, the vertical wheel–rail force, gear-meshing force, and dynamic transmission error (DTE) escalate. Furthermore, an increase in the order of wheel polygonization leads to a rise in the vertical wheel–rail force. In contrast, the gear-meshing force and DTE exhibit distinct trends at different speeds. At a speed of 20 km/h, these parameters increase by 51.34% and 0.29%, respectively. As the speed increases, the peaks of gear-meshing force and DTE occur at the 7th-order and 3rd-order polygon, respectively, suggesting that the dynamic response of the gear-transmission system becomes more sensitive to lower-order polygon effects at higher speeds, which necessitates greater attention during operation. Additionally, the phase difference of wheel polygonization exerts a significant influence on gear-meshing force under various conditions, such as in-phase, out-of-phase, 60° phase difference, and 120° phase difference. Therefore, in engineering applications, it is essential to consider the phase difference of wheel polygonization to alleviate excessive gear-meshing forces and ensure stable transmission performance. The findings of this paper offer insights into the dynamic evaluation and wheelset re-profiling of gear-transmission systems in urban railway vehicles. Full article

Noise, vibration and harshness analyses are of great interest for the latest developments of the gearboxes of electric vehicles. Gearboxes are now the main source of vibrations, since electric powertrains are much quieter than internal combustion engines. Traditionally, the simulation of the non-linear gear dynamics is studied by first performing a series of preliminary static analyses to compute the static transmission error (STE). The STE (i.e., in the form of varying mesh stiffness) is then accepted as the system’s excitation source to compute the dynamic transmission error (DTE). This paper presents a novel approach to analyze the non-linear dynamics of gears which does not require any preliminary static analyses. The method consists of a frequency–domain approach based on the Harmonic Balance Method (HBM) and the Alternating Frequency–Time (AFT) scheme, allowing for much faster simulations when compared to the widely used direct–time integration (DTI). The contact between the teeth is modeled as intermittent and penalty based with a varying gap. The time–varying gap between the teeth is initially approximated to a step function that guarantees the design contact ratio. The methodology introduced is tested on a lumped parameter model of a spur–gear pair already proposed and simulated in the literature. The results obtained with the novel approach are compared with the DTI simulation of the model as a reference. The excellent match between the different approaches validates the reliability of developed methodology. Full article

Objectives: Non-invasive ventilation (NIV) is a widely used treatment for neonatal respiratory distress syndrome (RDS). Data on diaphragm contractility and thickness during NIV is scarce. We aimed to describe changes in diaphragm thickness/contractility during NIV and to explore associations with NIV discontinuation failure. Methods: This is a single-center prospective study. Diaphragmatic ultrasound was performed weekly during NIV, then within 7 days from NIV discontinuation. Diaphragm thickness was measured at end-inspiration (DTI) and end-expiration (DTE). Diaphragm thickening fraction (DTF) was calculated as (DTI-DTE/DTE). The clinical characteristics of patients and NIV discontinuation failure were recorded. Univariate analysis, logistic regression and linear regression were performed to describe diaphragm features during NIV and associations with NIV discontinuation failure. Results: We studied 17 NIV cycles (median duration 21 days). Median DTE increased from 0.12 cm (SD 0.05) at the start of NIV to 0.15 cm (SD 0.04) at NIV discontinuation. The mean DTF decreased from 32.8 (SD 16.8) at the start of NIV to 25.6 (SD 8.9) at NIV discontinuation. NIV discontinuation failure occurred in 23.5% of infants and was associated with higher DTI and DTE at the start of NIV and with a more pronounced decrease in DTI and DTE over the NIV cycle, compared to infants with NIV discontinuation success. There were no differences in neonatal outcomes between the infants with NIV discontinuation failure vs. success. We did not find any significant predictors of NIV failure. Conclusions: Diaphragm thickness increased, whereas DTF decreased over time on NIV in preterm infants with RDS. NIV duration was not associated with changes in diaphragm trophism. NIV discontinuation failure was associated with thicker diaphragm at the start of NIV, as well as with a reduction in diaphragm trophism over the NIV cycle. Full article

Background/Objectives: Delayed tooth eruption (DTE) is a very challenging clinical situation, and the pathogenesis has been associated with local, systemic, and genetic factors. The aim of this presentation is to describe the management of such a case with delayed eruption of mandibular central incisors and canines. Methods: An 11-year-old female patient presented with DTE involving lower incisors (32, 42) and canines, seeking orthodontic treatment. Furthermore, lower permanent central incisors were congenitally missing while lower deciduous incisors were still in place. After a year-and-a-half of just monitoring the case and having suggested the extraction of deciduous first molars and canines, orthodontic treatment started with fixed appliances in the upper and lower jaw. First and second premolars gradually erupted after the precursor’s extraction. Lower canines and the two existing incisors were, after several months, surgically exposed and a gold chain apparatus was bonded on each one, while the closed eruption technique was chosen. A 0.17 × 0.25 stainless steel (SS) lingual wire, leaning on the buccal tubes of the lower molar bands and properly manipulated around them, was fitted in conjunction with the labial brackets and wires in order to facilitate the traction of the impacted teeth, which was carried out for one after the other using either an elastic chain or a second super-elastic wire. Results: All impacted teeth were finally restored to their proper place. The root of 71 did not present resorption, so the tooth was maintained in the lower arch while inter-proximal reduction was performed in the upper arch in the anterior region, in order to anticipate the lower missing incisor. Finally, a stable occlusion with proper contacts was achieved. Conclusions: Proper diagnosis, on-time extractions of deciduous teeth, and a well-designed treatment plan regarding space management and orthodontic traction of impacted teeth contributed to successful treatment outcomes in this DTE case. Full article

The evolution towards sixth-generation (6G) networks requires new architecture enhancements to support the broad device ecosystem, comprising users, machines, autonomous vehicles, and Internet-of-things devices. Moreover, high heterogeneity in the desired quality-of-service (QoS) is expected, as 6G networks will offer extremely low-latency and high-throughput services and error-free communication. This complex environment raises significant challenges in resource management while adhering to security and privacy constraints due to the plethora of data generation endpoints. Considering the advances in AI/ML-aided integration in wireless networks and recent efforts on the network data analytics function (NWDAF) by the 3rd generation partnership project (3GPP), this work presents an AI/ML-aided distributed trustable engine (DTE), collecting data from diverse sources of the 6G infrastructure and deploying ML methods for anomaly detection against diverse threat types. Moreover, we present the DTE architecture and its components, providing data management, AI/ML model training, and classification capabilities for anomaly detection. To promote privacy-aware networking, a federated learning (FL) framework to extend the DTE is discussed. Then, the anomaly detection capabilities of the AI/ML-aided DTE are presented in detail, together with the ML model training process, which considers various ML models. For this purpose, we use two open datasets representing attack scenarios in the core and the edge parts of the network. Experimental results, including an ensemble learning method and different supervised learning alternatives, show that the AI/ML-aided DTE can efficiently train ML models with reduced dimensionality and deploy them in diverse cybersecurity scenarios to improve anomaly detection in 6G networks. Full article

Information consumption (IC) has emerged as a critical driver of the digital transformation of enterprises (DTE) and sustainable corporate development, garnering significant attention in recent years. Nevertheless, research focused on the role of IC as a driving factor of the DTE remains relatively scarce. The information consumption pilot policy (ICPP), a key initiative aiming to foster the consumption of information products and services, plays an essential role in refining consumption systems and mechanisms, enhancing demand-side management, and facilitating the DTE. Using data from Chinese A-share listed companies, this study leverages the ICPP as a quasi-natural experiment and employs a difference-in-differences (DID) model to evaluate the effects and underlying mechanisms of IC on the DTE, with the objective of elucidating how IC drives the DTE. The findings indicate that IC significantly accelerates the DTE, a conclusion that remains robust across multiple validation tests. Further investigation reveals that IC has a stronger impact on digital transformation in non-state-owned enterprises, capital-intensive enterprises, technology-intensive enterprises, and growth-stage enterprises than in state-owned enterprises, labor-intensive enterprises, and enterprises in the maturity or decline stage. Similarly, IC demonstrates a more substantial influence on digital transformation in enterprises situated in southern cities, large-scale cities, and non-resource-dependent cities than in enterprises located in northern cities, small-scale cities, and resource-dependent cities. Mechanism analyses suggest that IC primarily drives the DTE through pathways such as technological innovation, the expansion of household consumption, and the advancement of financial digitization. Additionally, intellectual property protection is found to significantly enhance the impact of IC on the DTE. By investigating the drivers of the DTE from the perspective of digital consumption, this study not only provides a theoretical foundation for the advancement of China’s digital economy but also offers practical guidance and insights for fostering the DTE on a global scale. Full article

In an era where digital technologies are integral to daily life and sustainable education is increasingly critical, developing higher-order thinking skills with appropriate information and communication technology (ICT) support is crucial for achieving Sustainable Development Goals (SDGs). The purpose of this study was to examine synergies of systems thinking and technology-enhanced learning from the perspective of flow theory within the context of sustainable education. We surveyed more than 65 pre-service preschool teachers engaged in a design, technology, and engineering (DTE) course at the University of Ljubljana. Mapping of systems thinking revealed that pre-service preschool teachers needed support regarding feedback and understanding the interrelationship dimension of systems thinking—essential components of sustainable education. Predictive and mediation analyses yielded noteworthy results. Participants in the ICT-enhanced DTE course rated their cognitive and social engagement above the mid-point of the scale, with this higher engagement correlating with higher systems thinking crucial for sustainable education. In contrast, their aesthetic engagement was below the mid-point of the scale. Experiencing a flow state during ICT activities positively influenced systems thinking, particularly in terms of clear goals and autotelic experiences. Flow theory thus emerges as a solid and appropriate framework to use for studying synergies in technology-enhanced systems thinking for sustainable education. These findings underscore the importance of integrating systems thinking into curricula to enhance learning outcomes and prepare students for future challenges, thereby contributing to the achievement of SDGs through sustainable education. Full article

Muscle tissue is one of the most dynamic and plastic tissues of the mammalian body and covers different roles, such as force generation and metabolic control. Muscular proteomics provides an important opportunity to reveal the molecular mechanisms behind muscle pathophysiology. To ensure successful proteomic analysis, it is necessary to have an efficient and reproducible protein extraction method. This study aimed to evaluate the efficacy of two different extraction protocols of muscle samples for two-dimensional gel electrophoresis. In particular, mouse muscle proteins were extracted by an SDS-based buffer (Method A) and by a UREA/CHAPS/DTE/TRIS solution (Method B). The efficacies of the methods were assessed by performing an image analysis of the 2DE gels and by statistical and multivariate analyses. The 2DE gels in both preparations showed good resolution and good spot overlapping. Methods A and B produced 2DE gels with different means of total spots, higher for B. Image analysis showed different patterns of protein abundance between the protocols. The results showed that the two methods extract and solubilize proteins with different chemical–physical characteristics and different cellular localizations. These results attest the efficacy and reproducibility of both protein extraction methods, which can be parallelly applied for comprehensive proteomic profiling of muscle tissue. Full article

Non-wires alternatives and microgrid technologies are maturing and present great opportunities for electric utilities to increase the benefits they offer to their customers. They have the potential to decrease the cost of resolving traditional electrical system loading issues, contribute to carbon emissions reductions, and improve the electrical distribution system’s resilience to extreme weather events. The authors of this manuscript present a review of the research on microgrids and their practical applications. This is leveraged with the past work of the authors of this manuscript and other authors to develop specific objectives for microgrids, practical criteria for engineers to consider when deploying microgrids, stochastic methods to optimize microgrid designs, and black start requirements. This guidance is then used for the design of actual networked microgrids being deployed with adaptive boundaries. Full article

The dual-input single-output (DI-SO) cylindrical spur gear system possesses advantages such as high load-carrying capacity, precise transmission, and low energy loss. It is increasingly becoming a core component of power transmission systems in maritime vessels, aerospace, marine engineering, and construction machinery. In practical operation, the stability of the DI-SO cylindrical spur gear system is influenced by complex excitations. These excitations lead to nonlinear vibration, meshing instability, and noise, which affect the performance and reliability of the entire equipment. Hence, the dynamic performance of the DI-SO cylindrical spur gear system is thoroughly investigated in this research. The impact of excitations and nonlinear factors on the dynamic characteristics was investigated comprehensively. A comparative analysis of the gear system was conducted by establishing a bending–torsional coupling vibration analysis model under synchronous and asynchronous meshing conditions. Nonlinear factors such as periodic time-varying meshing stiffness, meshing damping, friction coefficient, friction arms, load sharing ratio, comprehensive transmission error, and backlash were considered in the proposed model. Then, the effect laws of excitations and nonlinear factors such as meshing frequency, driving load fluctuation, backlash, and comprehensive transmission error were analyzed. The results indicate that the dynamic characteristics exhibited staged stable and unstable states under different meshing frequencies and meshing conditions. At the medium-frequency meshing stage (0.96 × 10⁴~1.78 × 10⁴ Hz), alternating phenomena of multi-periodic, quasi-periodic, and chaotic motion states were observed. Moreover, the root mean square value (RMS) of the dynamic transmission error (DTE) in the asynchronized gear system was generally higher than that in the synchronized gear system. It was found that selecting the appropriate meshing condition could effectively reduce the amplitude of the DTE. Additionally, the dynamic performance could be significantly improved by adjusting control parameters such as driving load fluctuation (0~179 N), backlash (0.8 × 10⁻⁴~0.9 × 10⁻⁴ m), and comprehensive transmission error (7.9 × 10⁻⁴~9.4 × 10⁻⁴ m). The research results provide a theoretical guidance for the design and optimization of the DI-SO cylindrical spur gear system. Full article