To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This chapter introduces control schemes based on the PT-symmetric wireless power transfer (WPT) system. It begins with an overview of PT symmetry and its relevance to WPT, followed by detailed models and analyses based on circuit theory and coupled-mode theory. The chapter explores the output characteristics of PT-symmetric systems and presents control methods for optimizing output power through load identification. Experimental results are provided to validate the proposed control schemes, demonstrating their effectiveness in managing power transfer and enhancing system performance. The chapter highlights the innovative aspects of PT-symmetric WPT and its potential applications.
This chapter explores the application of wireless in-flight charging specifically for unmanned aerial vehicles (UAVs). It begins by outlining the benefits of this technology, including increased operational time and reduced maintenance needs. The chapter identifies key challenges such as managing continuous mutual inductance disturbances, developing lightweight pickup units, and enabling fast charging. Solutions to these challenges are discussed in detail, including innovations in system design. The chapter concludes with an overview of the construction and integration of wireless in-flight charging systems for UAVs, summarizing the current state of technology and future prospects.
Focusing on the design of magnetic couplers for UAV wireless charging, this chapter addresses various design strategies for optimizing power transfer efficiency. It covers the design of pickup coils, including embedded lightweight squirrel-cage coils, hollow pickup coils suitable for in-flight UAVs, and onboard integration-based coils. The chapter also examines different magnetic coupling structures, such as orthogonal magnetic couplers, free-rotation asymmetric couplers, and compact omnidirectional magnetic structures. Each design approach is evaluated for its effectiveness in improving wireless power transfer in UAV applications, providing insights into practical implementation and performance optimization.
This chapter addresses techniques for extending the charging range of PT-symmetric WPT systems. It begins with an introduction to range extension methods and then explores the use of S/SLDC high-order topologies for improved performance. The chapter includes system analysis, modelling, and comparison with other topologies, focusing on negative resistance design to enhance range. Additionally, it presents flexible charging range extension methods, such as autonomous on-off keying modulation schemes, and discusses their system output characteristics and control algorithm implementation. Experimental verification supports the proposed methods, showcasing advancements in expanding the operational range of PT-symmetric WPT systems.
This chapter details advanced control strategies for wireless charging systems used in UAVs. It begins with an introduction to control challenges specific to wireless charging and then discusses model-predicted control approaches, particularly those using high-order LCC-P topologies. Key topics include system modelling, mutual inductance prediction, and controller design, supported by both simulation and experimental verification. The chapter also covers rotating-coordinate-based mutual inductance estimation, including system modelling in the dq synchronous reference frame and the αβ-to-dq transformation. This section emphasizes the importance of accurate control for efficient and reliable wireless power transfer.
This chapter introduces the principles and mechanisms behind wireless power transfer (WPT), focusing on inductive power transfer systems. It begins with the historical development of WPT and then delves into the fundamental aspects of inductive power transfer, including general configurations. The chapter provides a detailed examination of theoretical models, such as the loosely coupled transformer model, T-model, and M-model, and compares their effectiveness. It further explores compensation networks, including series and parallel types, and discusses transmission performance metrics such as output power, transfer efficiency, and their interrelationships. This comprehensive overview establishes the foundational knowledge necessary for understanding advanced WPT systems.
Discover the principles of wireless power transfer for unmanned aerial vehicles, from theoretical modelling to practical applications. This essential guide provides a complete technical perspective and hands-on experience. It combines in-depth theoretical models, such as T-models and M-models, with practical system design, including wireless charging system construction. It presents systematic solutions to real-world challenges in UAV wireless charging, such as mutual inductance disturbances and lightweight units. Providing the resources to tackle complex industry problems this book covers the latest technological insights including advanced control methods, such as PT-symmetric WPT system control schemes and charging range extension techniques. Ideal for professional engineers, designers, and researchers, it provides the tools needed to innovate in UAV technology and power systems. Whether you're developing new systems or optimizing existing ones, this comprehensive resource delivers the insights and techniques to drive progress in wireless power transfer for unmanned aircraft.
Schizophrenia progresses through high-risk, first-episode, and chronic stages, each associated with altered spontaneous brain activity. Resting state functional MRI studies highlight these changes, but inconsistencies persist, and the genetic basis remains unclear.
Methods
A neuroimaging meta-analysis was conducted to assess spontaneous brain activity alterations in each schizophrenia stage. The largest available genome-wide association study (GWAS) summary statistics for schizophrenia (N = 53,386 cases, 77,258 controls) were used, followed by Hi-C-coupled multimarker analysis of genomic annotation (H-MAGMA) to identify schizophrenia-associated genes. Transcriptome-neuroimaging association and gene prioritization analyses were performed to identify genes consistently linked to brain activity alterations. Biological relevance was explored by functional enrichment.
Results
Fifty-two studies met the inclusion criteria, covering the high-risk (Nhigh-risk = 409, Ncontrol = 475), first-episode (Ncase = 1842, Ncontrol = 1735), and chronic (Ncase = 1242, Ncontrol = 1300) stages. High-risk stage showed reduced brain activity in the right median cingulate and paracingulate gyri. First-episode stage revealed increased activity in the right putamen and decreased activity in the left gyrus rectus and right postcentral gyrus. Chronic stage showed heightened activity in the right inferior frontal gyrus and reduced activity in the superior occipital gyrus and right postcentral gyrus. Across all stages, 199 genes were consistently linked to brain activity changes, involved in biological processes such as nervous system development, synaptic transmission, and synaptic plasticity.
Conclusions
Brain activity alterations across schizophrenia stages and genes consistently associated with these changes highlight their potential as universal biomarkers and therapeutic targets for schizophrenia.
In this paper, a wideband reconfigurable reflectarray antenna (RRA) using 1-bit resolution for beam scanning with two-dimensional (2D) capability is presented at Ku-band. A 1-bit RRA element with a rectangular patch embedded with slots is proposed for broadband operation. Each element is equipped with a single PIN diode, allowing for resonance tuning while ensuring low cost and minimal power consumption. According to the simulation results, the proposed element is capable of 1-bit phase resolution with a phase difference of ${180^\circ \pm 20^\circ}$ stability from 11.27 to 13.74 GHz, which corresponds to an approximate bandwidth of 19.75%. To demonstrate its capabilities, we developed, fabricated, and tested a wideband electronically RRA with ${14 \times 14}$ elements. The experimental results demonstrate that the realized maximum gain in the broadside direction is 21.1 dB with a peak aperture efficiency of 20.9%. 2D beam scanning within ${\pm50^\circ}$ angular range are obtained and the scan gain reduction is 1.88 dB for ${-50^\circ}$ scanned beam in E-plane while 2.21 dB for ${50^\circ}$ scanned beam in H-plane. The 1-dB gain bandwidth of the RRA is 15.1%.
Little is known regarding the shared genetic architecture underlying the phenotypic associations between depression and preterm birth (PTB). We aim to investigate the genetic overlap and causality of depression with PTB.
Methods
Leveraging summary statistics from the largest genome-wide association studies for broad depression (Ntotal = 807,533), major depression (Ntotal = 173,005), bipolar disorder (Ntotal = 414,466), and PTB (Ntotal = 226,330), we conducted a large-scale genome-wide cross-trait analysis to assess global and local genetic correlations, identify pleiotropic loci, and infer potential causal relationships
Results
Positive genetic correlations were observed between PTB and broad depression (rg = 0.242), major depression (rg = 0.236), and bipolar disorder (rg = 0.133) using the linkage disequilibrium score regression, which were further verified by the genetic covariance analyzer. Local genetic correlation was identified at chromosome 11q22.3 (harbors NCAM1-TTC12-ANKK1-DRD2) for PTB with depression. Cross-trait meta-analysis identified two loci shared between PTB and broad depression, two loci shared with major depression, and five loci shared with bipolar disorder, among which three were novel (rs7813444, rs3132948 and rs9273363). Mendelian randomization demonstrated a significantly increased risk of PTB for genetic liability to broad depression (odds ratio [OR]=1.30; 95% confidence interval [CI]: 1.11-1.52) and major depression (OR=1.27; 95%CI: 1.08-1.49), and the estimates remained significant across the sensitivity analyses.
Conclusions
Our findings demonstrate an intrinsic link underlying depression and PTB and shed novel light on the biological mechanisms, highlighting an important role of early screening and effective intervention of depression in PTB prevention, and may provide novel treatment strategies for both diseases.
MicroRNAs (miRNAs) alterations in patients with bipolar disorder (BD) are pivotal to the disease’s pathogenesis. Since obtaining brain tissue is challenging, most research has shifted to analyzing miRNAs in peripheral blood. One innovative solution is sequencing miRNAs in plasma extracellular vesicles (EVs), particularly those neural-derived EVs emanating from the brain.
Methods
We isolated plasma neural-derived EVs from 85 patients with BD and 39 healthy controls (HC) using biotinylated antibodies targeting a neural tissue marker, followed by miRNA sequencing and expression analysis. Furthermore, we conducted bioinformatic analyses and functional experiments to delve deeper into the underlying pathological mechanisms of BD.
Results
Out of the 2,656 neural-derived miRNAs in EVs identified, 14 were differentially expressed between BD patients and HC. Moreover, the target genes of miR-143-3p displayed distinct expression patterns in the prefrontal cortex of BD patients versus HC, as sourced from the PsychENCODE database. The functional experiments demonstrated that the abnormal expression of miR-143-3p promoted the proliferation and activation of microglia and upregulated the expression of proinflammatory factors, including IL-1β, IL-6, and NLRP3. Through weighted gene co-expression network analysis, a module linking to the clinical symptoms of BD patients was discerned. Enrichment analyses unveiled these miRNAs’ role in modulating the axon guidance, the Ras signaling pathway, and ErbB signaling pathway.
Conclusions
Our findings provide the first evidence of dysregulated plasma miRNAs within neural-derived EVs in BD patients and suggest that neural-derived EVs might be involved in the pathophysiology of BD through related biological pathways, such as neurogenesis and neuroinflammation.
Social determinants of health (SDHs) exert a significant influence on various health outcomes and disparities. This study aimed to explore the associations between combined SDHs and mortality, as well as adverse health outcomes among adults with depression.
Methods
The research included 48,897 participants with depression from the UK Biobank and 7,771 from the US National Health and Nutrition Examination Survey (NHANES). By calculating combined SDH scores based on 14 SDHs in the UK Biobank and 9 in the US NHANES, participants were categorized into favourable, medium and unfavourable SDH groups through tertiles. Cox regression models were used to evaluate the impact of combined SDHs on mortality (all-cause, cardiovascular disease [CVD] and cancer) in both cohorts, as well as incidences of CVD, cancer and dementia in the UK Biobank.
Results
In the fully adjusted models, compared to the favourable SDH group, the hazard ratios for all-cause mortality were 1.81 (95% CI: 1.60–2.04) in the unfavourable SDH group in the UK Biobank cohort; 1.61 (95% CI: 1.31–1.98) in the medium SDH group and 2.19 (95% CI: 1.78–2.68) in the unfavourable SDH group in the US NHANES cohort. Moreover, higher levels of unfavourable SDHs were associated with increased mortality risk from CVD and cancer. Regarding disease incidence, they were significantly linked to higher incidences of CVD and dementia but not cancer in the UK Biobank.
Conclusions
Combined unfavourable SDHs were associated with elevated risks of mortality and adverse health outcomes among adults with depression, which suggested that assessing the combined impact of SDHs could serve as a key strategy in preventing and managing depression, ultimately helping to reduce the burden of disease.
The aim of this study is to explore how large language models (LLMs) integrated with structured versus unstructured concept generation techniques (CGTs) influence designers’ creative thinking processes and outputs. Using human–human collaboration (HHC) as a baseline, a 2 × 2 mixed factorial design was adopted to investigate the effects of collaborator type (between-subjects: LLM-based agents vs. experienced designers) and CGT type (within-subjects: brainstorming vs. TRIZ). Two LLM-based agents, IntelliStorm and EvoluTRIZ, were developed for the study, with 32 participants randomly assigned to either the HHC or human–agent collaboration (HAC) groups. Brain activity was measured using functional near-infrared spectroscopy, while outputs were assessed through expert evaluations. Results showed that designers exhibited lower cognitive load, better cognitive resource coordination, and enhanced fluency and flexibility in thinking in HAC than in HHC. Moreover, distinct patterns were revealed in different CGTs: brainstorming activated the right dorsolateral prefrontal cortex (PFC) as the core connectivity region, enhancing ideational fluency, whereas TRIZ activated the left dorsolateral PFC, facilitating refined thinking. Although HAC demonstrated stronger overall performance, HHC retained unique advantages in originality. This research offers novel neuroscientific insights and provides evidence-based guidance for developing more effective LLM-based design agents.
To fully understand resilience and to inform resilience-promoting interventions, it is important to explore how resilience develops and the factors that influence it. Using a multidimensional approach that considers both well-being resilience (higher than expected wellbeing after adversity) and depression resilience (lower than expected depression after adversity), this study examined resilience trajectories among Chinese 0adolescents and the associations of gratitude and perceived stress with resilience trajectories. Data from a four-wave longitudinal study were analyzed from 563 Chinese adolescents (mean age at Time 1 = 12.83 years, 51.87% boys). Parallel-process latent class growth modeling identified four distinct trajectories of resilience development: flourishing resilience (increasing resilience; 21.67%), increasing wellbeing resilience but decreasing depression resilience (28.24%), declining resilience (29.48%), and increasing depression resilience but decreasing wellbeing resilience (20.61%). Gratitude was associated with greater odds of being in the flourishing resilience group. Furthermore, perceived stress was associated with lower odds of being in the flourishing resilience group and higher odds of being in the declining resilience group. The findings suggest that resilience is a dynamic and multidimensional construct with highly heterogeneous developmental trajectories. Gratitude and perceived stress may be effective targets for interventions to enhance adolescent resilience.
Depression and anxiety are prevalent mental health disorders. While sleep duration has been extensively studied, sleep regularity may play a critical role. We aimed to examine associations between objectively measured sleep regularity and incident depression and anxiety and to investigate whether meeting recommended sleep duration modifies these associations.
Methods
In 79,666 UK Biobank participants without baseline depression or anxiety, wrist accelerometers worn for 7 days yielded a sleep regularity index (SRI) and average sleep duration. SRI was categorized as irregular (≤51), moderately irregular (52–70), or regular (≥71). Sleep duration was classified by age-specific recommendations (7–9 hours for ages 18–64 years; 7–8 hours for over 65 years). Cox regression models assessed associations between sleep parameters and mental health outcomes.
Results
During a median follow-up of 7.5 years, 1,646 participants developed depression, and 2,097 developed anxiety. Compared to irregular sleepers, regular sleepers had a 38% lower depression risk (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.52–0.73) and a 33% lower anxiety risk (HR, 0.67; 95%CI, 0.58–0.77). Participants with both irregular sleep and nonrecommended duration exhibited the highest risks (depression HR, 1.91; 95%CI, 1.55–2.35; anxiety HR, 1.61; 95%CI, 1.35–1.93). Notably, irregular sleepers who met duration guidelines still faced elevated risks (depression HR, 1.48; 95%CI, 1.18–1.86; anxiety HR, 1.35; 95%CI, 1.11–1.64).
Conclusions
Greater sleep regularity is independently associated with lower depression and anxiety risk regardless of sleep duration, suggesting that sleep–wake consistency should be considered in mental health promotion strategies alongside traditional sleep duration recommendations.