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Near time-optimal trajectory optimisation for drones in last-mile delivery using spatial reformulation approach
No full textSeeking a computationally efficient and time-optimal trajectory for drones is crucial for saving time and energy costs, especially in the field of drone parcel delivery. Still, last-mile drone delivery is a challenge in urban environments, due to the existence of complex spatial constraints arising from high-rise buildings and the inherent non-linearity of the system dynamics. This paper presents a three-stage method to address the trajectory optimisation problem in a constrained environment. First, the kinematics and dynamics of the quadcopter are reformulated in terms of spatial coordinates, which enables the explicit evaluation of the progress of the path. Second, an efficient flight corridor generation algorithm is presented based on the transverse coordinates of the spatial reformulation. Third, the nonlinear model predictive control (NMPC)-based optimal control problem with obstacle avoidance is formulated for solving the time-optimal trajectory. Compared to the true time-optimal trajectory, the flight time of the near time-optimal trajectory is 3.10% longer than the true time-optimal trajectory, but with a 92.5% reduction in computation time. Numerical simulations based on an illustrative scenario as well as a real-world urban environment are conducted. Results demonstrate the effectiveness of the proposed method in generating near time-optimal trajectory but with a reduced computational burden
Exploring WNT pathway dysregulation in serrated colorectal cancer for improved diagnostic and therapeutic strategies
No full textBackground: Serrated colorectal cancer (SCC) is a rare and aggressive subtype of colorectal cancer. Identifying SCC is crucial due to its high mortality rate and limited therapeutic options. Traditional methods to identify BRAF hotspot mutations and MLH1 methylation are insufficient in clinical practice. This study aims to explore the WNT pathway alterations in the CRC and to develop a WNT-derived subtyping model to identify SCC patients by using multi-OMICs data. Methods: We included multi-omics data of 1751 colorectal cancer patients from the TCGA and GEO databases, and single-cell transcriptome data of 33 normal and cancer tissues from the SMC study cohort. The comprehensive study process incorporated unsupervised clustering, enrichment analysis, and statistical analysis. Results: In this study, we investigated WNT pathway alterations in SCC by integrating both bulk and single-cell data into the multi-OMICs framework. The SCC subtype demonstrated significant WNT pathway heterogeneity and a more stable genomic structure. These findings support the development of a WNT-derived subtyping model that accurately identifies SCC patients across different CRC cohorts. In addition, the SCC subtype also presented a distinct immune microenvironment characterized by CD8+ T cell exhaustion. Finally, we utilized drug perturbation data to explore the potential drug targets for this severe cancer subtype. Conclusion: We developed a WNT-derived subtyping method to identify SCC from canonical CRC, which enhances the molecular understanding of this severe cancer subtype and provides potential therapeutic strategies. Our findings suggest that SCC patients may benefit from the HSP90 inhibitor NVP-AUY922, highlighting its potential as a targeted therapy.</p
Recent progress on high-precision construction of nanoarchitectured SERS substrates for ultrasensitive bio-medical sensors
Full text linkSurface-enhanced Raman spectroscopy (SERS) has evolved from a laboratory technique to a practical tool for ultra-sensitive detection, particularly in the biomedical field, where precise molecular identification is crucial. Despite significant advancements, a gap remains in the literature, as no comprehensive review systematically addresses the high-precision construction of SERS substrates for ultrasensitive biomedical detection. This review fills that gap by exploring recent progress in fabricating high-precision SERS substrates, emphasizing their role in enabling ultrasensitive bio-medical sensors. We carefully examine the key to these advancements is the precision engineering of substrates, including noble metals, semiconductors, carbon-based materials, and two-dimensional materials, which is essential for achieving the high sensitivity required for ultrasensitive detection. Applications in biomedical diagnostics and molecular analysis are highlighted. Finally, we address the challenges in SERS substrate preparation and outline future directions, focusing on improvement strategies, design concepts, and expanding applications for these advanced materials.published_or_final_versio
Three-dimensional wake division and scale recognition after a multi-scale fractal tree based on Hilbert-Huang transform
No full textThe aerodynamic performance of fractal geometries is a critical concern in engineering, such as urban trees, whose multi-scale wake structures warrant detailed examination. Identifying the contributions from multiple sub-scale tree geometries to wake dynamics requires decomposition and recognition of characteristic wake scales, which can encounter scale mixing in conventional methods such as the fast-fourier transform (FFT) and bare empirical mode decomposition (EMD). This study analyzes the wake characteristics behind fractal trees with varying crown porosities using the Hilbert-Huang transform (HHT). HHT decomposes the wake by EMD into intrinsic mode functions (IMFs) first, then determines each IMF's instantaneous frequency and amplitude by Hilbert spectral analysis. The statistical peaked frequency, which is calculated via the marginal Hilbert spectrum, reveals a similar major scale but a different spatial energy distribution compared with the FFT. The statistical joint probability density function (JPDF) of the instantaneous frequency and amplitude denotes consistent high-occurrence peaks at Sth = 0.2, 0.6, and 1.2, recommending including 1, 0.33, and 0.17 h into urban greening parameterization. The reconstructed peaked turbulence field exhibits specific spatial distribution patterns. This finding validates the bond between sub-scale geometries and JPDF peaks. The interaction of different peak scales is investigated to look into scale coherence. The central frequency and oval-like distribution slope offer a novel perspective on wake instability assessment. Additionally, the momentum fluxes driven by different peaked scales are examined, elucidating the contributions of sub-scale tree geometries to wake dynamics and pollutant transport, providing valuable guidance for optimizing urban greening design
Alpha-aminobutyric acid ameliorates diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD) progression in mice via enhancing AMPK/SIRT1 pathway and modulating the gut-liver axis
No full textAlpha-aminobutyric acid (ABA) is a nonproteinogenic amino acid, a metabolite which could be generated from the metabolism of methionine, threonine, serine and glycine or as a gut-microbiome-derived metabolite. Changes in ABA levels have been embroiled in metabolic dysfunction-associated steatotic liver disease (MASLD) intervention studies, but their relation to MASLD pathogenesis remains unclear. Hence, this present study aimed to investigate the effect of oral ABA supplementation on the progression of a high fat/high cholesterol diet (HFD) induced MASLD mice model. ABA was found to remodel the gut microbiome composition and ameliorate MASLD parameters in HFD-fed mice. ABA mitigated HFD-induced gain in liver weight, hepatic steatosis, insulin resistance, serum and hepatic triglyceride levels, and liver cholesterol levels. Modulation of lipid metabolism was observed in the liver, in which expression of proteins and/or genes involved in de novo lipogenesis were suppressed, while those involved in fatty acid oxidation and autophagy were upregulated together with cellular antioxidant capacity, in addition to the enhancement of the AMPK/SIRT1 pathway. ABA reshaped the gut composition by enriching nine bacterial species, including Helicobacter hepaticus, Desulfovibrio sp. G11, Parabacteroides distasonis, and Bacteroides fragilis, while diminishing the abundance of 16 species, which included four Helicobacter species. KEGG pathway analysis of microbial functions found that ABA impeded secondary bile acid biosynthesis – which was reflected in the faecal BA composition analysis. Notably, ABA also inhibited ileal FXR-Fgf15 signaling, allowing for increased hepatic Cyp7a1 expression to eliminate cholesterol buildup in the liver. Overall, our findings indicate that ABA could be used as a promising therapeutic approach for the intervention of MASLD
Altered salivary profiles in adolescents with dental caries and central obesity: a cross-sectional study
No full textObjectives: To explore the associations among salivary profiles, dental caries, and central obesity in adolescents. Methods: This cross-sectional study involved 184 adolescents aged 12–15 years. Anthropometric measurements and dental examinations were conducted. The participants were sex- and age-matched and classified into four groups: 1) normal waist-to-height ratio (WHtR) without caries (NW+NC), 2) high WHtR and without caries (HW+NC), 3) with normal WHtR and caries (NW+C), or 4) high WHtR with caries (HW+C). Unstimulated and stimulated saliva samples were collected to assess salivary flow rates, pH, and buffering capacity. Salivary biomarkers, including lipoprotein-associated phospholipase A2 (Lp-PLA2), secretory phospholipase A2 group IIA (sPLA2-IIA), interleukin-6, and serum amyloid A, were quantified using enzyme-linked immunosorbent assay (ELISA). Quantitative real-time polymerase chain reaction (qPCR) was used to measure Streptococcus mutans and total bacterial load. Results: Significantly different salivary Lp-PLA2 levels, sPLA2-IIA output, total bacterial load, Streptococcus mutans abundance, and flow rates were observed among the four groups. The NW+C, HW+NC, and HW+C groups had significantly higher salivary Lp-PLA2 levels and significantly lower salivary flow rates than the NW+NC group. The HW+C group had a significantly lower salivary sPLA2-IIA output and higher total salivary bacterial load than the NW+C group. Conclusions: Both dental caries and central obesity are associated with elevated Lp-PLA2 and decreased salivary gland secretory function. Adolescents with both conditions showed decreased salivary sPLA2-IIA output and increased salivary bacterial load, which may indicate compromised oral antimicrobial status that warrants further investigation. Clinical significance: Observed changes in salivary profiles may offer preliminary insights into the mechanisms linking obesity and oral health, potentially informing the development of more tailored oral health programs for children and adolescents with obesity
A case study of teachers’ generative artificial intelligence integration processes and factors influencing them
Full text linkHow schoolteachers integrate generative artificial intelligence (GenAI) into their teaching remains underexplored. This case study of 22 teachers from Guangdong delineates four GenAI user types, i.e., cautious adapters, efficiency enhancers, technology enthusiasts, and pedagogical innovators; groups teachers’ GenAI integration into five levels, from low to high; and examines how transformation of GenAI integration is influenced by individual, technological, and environmental factors. These findings extend the Substitution, Augmentation, Modification, and Redefinition (SAMR) model into PSAMR – the “P” stands for “Prohibition” – emphasizing GenAI’s dynamic, controversial nature. They also indicate that, during integration, educators should focus more on human factors than on tools’ functionalities.published_or_final_versio
Analysis of Ion Cyclotron Waves during Cassini’s Flybys of Enceladus
No full textIon cyclotron waves (ICWs) are ubiquitous phenomena within Saturn’s magnetosphere, particularly in the vicinity of Enceladus. This study focuses on the Cassini spacecraft’s flyby data of Enceladus to investigate the spatial distribution and properties of ICWs. We categorize ICWs into two distinct types based on their frequency characteristics: Type I, with frequencies deviating from the local ion cyclotron trend, detected during high-inclination flybys; and Type II, with frequencies closely following the local trend, observed during horizontal flybys. Moreover, we identify the simultaneous detection of ICWs and magnetosonic waves within Saturn’s magnetosphere, providing new insights into their generation and propagation mechanisms. Our results show that ICWs serve as crucial diagnostic tools for evaluating local plasma conditions and the dynamics of Saturn’s magnetosphere. Furthermore, this study highlights the broader implications of ICWs for comparative planetary magnetospheric research, providing guidance for investigating similar processes at other planetary systems, such as Jupiter’s moons Io and Europa
An Unusual Cause of Complete Atrioventricular Block and Aortic Regurgitation
No full textWe report a rare case of Behçet's disease (BD) causing aortic regurgitation and complete atrioventricular block (AVB) in conjunction with pacemaker pocket infection. We emphasize the need to consider the possibility of BD in young and middle-aged patients who present with aortic valve prolapse with regurgitation combined with complete AVB with elevated inflammatory markers.Behçet's disease (BD) is a progressive diffuse inflammatory vasculitis characterized by recurrent oral and genital ulcers and ocular inflammation. Cardiac involvement is a rare complication of BD. Two cases of BD causing aortic regurgitation (AR) as well as complete atrioventricular block (AVB) have been reported previously; however, in this case report, we describe a case in which BD not only caused AR and complete AVB, but also coexisted with pacemaker pocket infection.</p