While digital twins (DTs) have recently gained prominence as a viable option for creating reliable asset representations, many existing frameworks and architectures in the literature involve the integration of different technologies and paradigms, including the Internet of Things (IoTs), data modeling, and machine learning (ML). This complexity requires the orchestration of these different technologies, often resulting in subsystems and composition frameworks that are difficult to seamlessly align. In this paper, we present a scalable compositional framework designed for the development of a DT-based production management system (PMS) with advanced production monitoring capabilities. The conducted approach used to design the compositional framework utilizes the Factory Design and Improvement (FDI) methodology. Furthermore, the validation of our proposed framework is illustrated through a case study conducted in a phosphate screening station within the context of the mining industry. Full article

With the construction and development of the smart grid, the power business puts higher requirements on the communication capability of the network. In order to improve the energy efficiency of the space–air–ground-integrated power three-dimensional fusion communication network, we establish an optimization problem for joint air platform (AP) flight path selection, ground power facility (GPF) association, and power control. In solving the problem, we decompose the problem into two subproblems, one is the AP flight path selection subproblem and the other is the GPF association and power control subproblem. Firstly, based on the GPF distribution and throughput weights, we model the AP flight path selection subproblem as a Markov Decision Process (MDP) and propose a multi-agent iterative optimization algorithm based on the comprehensive judgment of GPF positions and workload. Secondly, we model the GPF association and power control subproblem as a multi-agent, time-varying K-armed bandit model and propose an algorithm based on multi-agent Temporal Difference (TD) learning. Then, by alternately iterating between the two subproblems, we propose a reinforcement learning (RL)-based joint optimization algorithm. Finally, the simulation results indicate that compared to the three baseline algorithms (random path, average transmit power, and random device association), the proposed algorithm improves an overall energy efficiency of the system of 16.23%, 86.29%, and 5.11% under various conditions (including different noise power levels, GPF bandwidth, and GPF quantities), respectively. Full article

Although research has shown that moral distress harms mental health in diverse populations, information on potential moderators of such associations is scarce. In a sample of sub-Saharan African nurses, we examined the link between moral distress and depressive symptoms. We explored for whom and when such relationships may hold with regard to gender, age, and work experience. Participants consisted of 398 nurses drawn from a tertiary healthcare institution in southeastern Nigeria. Data were collected using the Moral Distress Questionnaire (MDQ) for clinical nurses, and the Center for Epidemiological Studies Depression Scale Revised (CEDS-R). Hayes regression-based macro results for the moderation effects indicated that the association of high moral distress with increased depressive symptoms was robust for women but not significant for men. Although older age and higher years of nursing experience were associated with reduced symptoms of depression, nurses’ age and years of work experience did not moderate the relationship between moral distress and depressive symptoms. To promote mental well-being and preserve the integrity of nurses, gender-based differentials in how morals contribute depressive symptoms should be considered in policy and practice. Full article

Existing research in metasurface design was based on trial-and-error high-intensity iterations and requires deep acoustic expertise from the researcher, which severely hampered the development of the metasurface field. Using deep learning enabled the fast and accurate design of hypersurfaces. Based on this, in this paper, an integrated learning approach was first utilized to construct a model of the forward mapping relationship between the hypersurface physical structure parameters and the acoustic field, which was intended to be used for data enhancement. Then a dual-feature fusion model (DFCNN) based on a convolutional neural network was proposed, in which the first feature was the high-dimensional nonlinear features extracted using a data-driven approach, and the second feature was the physical feature information of the acoustic field mined using the model. A convolutional neural network was used for feature fusion. A genetic algorithm was used for network parameter optimization. Finally, generalization ability verification was performed to prove the validity of the network model. The results showed that 90% of the integrated learning models had an error of less than 3 dB between the real and predicted sound field data, and 93% of the DFCNN models could achieve an error of less than 5 dB in the local sound field intensity. Full article

Water resource management has emerged as a pivotal concern within arid regions in recent times. The water footprint (WFP) index stands out as a principal gauge for facilitating comprehensive watershed management. This study endeavors to compute the WFP of diverse agricultural products encompassing major crops, orchards, cucurbits, and medicinal plants across arid regions. This research focuses on three distinct climate scenarios: the Shazand Plain with a semidry climate, the Khomein Plain characterized by a dry climate, and the Saveh Plain exhibiting a very dry climate. This study also seeks to ascertain the climate most conducive to cultivating crops from a WFP (green, blue, and gray) perspective. To achieve these objectives, this study employed the CropWat family software to determine crop water requirements, as well as considering crop yield and relevant parameters for calculations. The findings of the investigation unveiled that the cultivated areas in the respective climates amounted to 19,479 ha (semidry), 18,166 ha (dry), and 41,682 ha (very dry). These areas were allocated as follows: 88%, 85%, and 55% for crops; 11%, 13%, and 40% for orchards; and 1%, 2%, and 5% for cucurbit crops. Importantly, the very dry climate was predisposed to allocating more land for low-water-demand orchards. Among the major crops, wheat occupied 44%, 39%, and 43% of the total areas in the semidry, dry, and very dry climates, respectively. Analyzing the overall agricultural output in these climates, it was revealed that over 79%, 69%, and 66% of production correlated with crops; 17%, 19%, and 22% with orchards; and 4%, 12%, and 12% with cucurbits, respectively. In terms of water consumption, maize and apples emerged as the highest performers, with varying consumption patterns across different crops. Interestingly, canola exhibited a substantially higher WFP, surpassing wheat and barley by 56.48% and 58.85%, respectively, in dry climates. Cucurbit crops, on the other hand, displayed a lower WFP in dry climates, which could potentially encourage their cultivation. The influence of climate warming on canola’s WFP_gray introduced complexity, challenging the conventional correlation between WFP and yields. Medicinal plants consistently demonstrated lower WFP values, underscoring the need for deliberate and considerate cultivation decisions in this regard. Full article

Cyclin-dependent kinase 2 (CDK2) is a key cell cycle regulator, with essential roles during G1/S transition. The clinicopathological significance of CDK2 in ductal carcinomas in situ (DCIS) and early-stage invasive breast cancers (BCs) remains largely unknown. Here, we evaluated CDK2’s protein expression in 479 BC samples and 216 DCIS specimens. Analysis of CDK2 transcripts was completed in the METABRIC cohort (n = 1980) and TCGA cohort (n = 1090), respectively. A high nuclear CDK2 protein expression was significantly associated with aggressive phenotypes, including a high tumour grade, lymph vascular invasion, a poor Nottingham prognostic index (all p-values < 0.0001), and shorter survival (p = 0.006), especially in luminal BC (p = 0.009). In p53-mutant BC, high nuclear CDK2 remained linked with worse survival (p = 0.01). In DCIS, high nuclear/low cytoplasmic co-expression showed significant association with a high tumour grade (p = 0.043), triple-negative and HER2-enriched molecular subtypes (p = 0.01), Comedo necrosis (p = 0.024), negative ER status (p = 0.004), negative PR status (p < 0.0001), and a high proliferation index (p < 0.0001). Tumours with high CDK2 transcripts were more likely to have higher expressions of genes involved in the cell cycle, homologous recombination, and p53 signaling. We provide compelling evidence that high CDK2 is a feature of aggressive breast cancers. The clinical evaluation of CDK2 inhibitors in early-stage BC patients will have a clinical impact. Full article

Pedestrianization is a significant discourse focus within urban planning and design research. However, the need for more clarity from the inconsistent use of near-synonym concepts or terms necessitates attention. This review article addresses this issue through a comprehensive analysis of synonym proliferation in pedestrian research, culminating in developing a robust “near synonymous toolkit” and “synonym selection framework”. Employing a linear snowball sampling technique, numerical analysis, and a qualitative content analysis-based summative approach, we examined sixteen peer-reviewed articles from 11 scientific journals. Through systematic classification based on consistency and variability, the summative review identifies three primary groups of near synonyms: dominant and widely utilized conceptual or terminological near synonymy in pedestrianization in the urban planning and design literature, near synonyms directly associated with a pedestrian, pedestrianize, and those indirectly linked to another conceptual or terminological synonymy. Further analysis delves into the nature of near-synonym concepts or terms, revealing three discernible patterns: the use of distinct, precise concepts or terms with near-synonym meanings, similar concepts or terms conveying divergent meanings, and the juxtaposition of unrelated vocabulary lacking semantic resemblance. These insights illuminate semantic relationships within the studied vocabulary, underscoring the importance of addressing inconsistency for clarity, precision, and coherence in scientific discourse. By offering practical guidance through the proposed framework, this study empowers academic researchers to navigate synonym selection adeptly, thereby enhancing the caliber of scholarly writing in urban planning and design. Full article

Humanity development is associated with higher spiritual and social behaviour and financial shape, which is an undeniable factor of urbanisation. Previously, in areas of georesource concentration, cities and settlements were formed with people exploiting these georesources. However, imperfect technologies lead to rapid depletion of reserves and industrial and environmental disasters, which affect the vulnerability of cities and the people living in them. The analysis of applied technologies has demonstrated that potash extraction is accompanied by a low recovery ratio, high mine accidents, and environmental problems. The principles of sustainable development of geo-resources for the creation of mining technologies that ensure industrial safety, environmental sustainability, and extending the life of the mining enterprise to save working places will reduce the vulnerability of cities. This article proposes the use of the room-and-pillar mining method with the replacement of natural supports with artificial ones. Three-stage stoping with backfill is considered. Numerical modelling has shown stabilisation of mining and geomechanical processes, which confirms the prospectivity of the method with backfill. For these purposes, this research presents a new backfill composition based on local industrial waste. Schemes of backfill preparation and feeding into the mined-out space are proposed. The proposed technology, based on the principles of sustainable development of georesources, is the foundation for an economically profitable, environmentally friendly, and socially responsible mining enterprise. The implementation of the principles of sustainable development of georesources will allow for the preservation of cities and reduce their vulnerability. Full article

This study presents a numerical approach to the design and optimization of centrifugal impellers used in the pumps of active thermal control systems of spacecraft. Although launch costs have shrunk in the last decade, the performance requirements, such as efficiency and reliability, have increased, as such systems are required to work up to 15 years, depending on the mission. To that effect, our paper deals with the first step in this pump design, namely the hydraulic optimization of the impeller. Constructively, this type of impeller allows for certain balancing systems and labyrinth seals to be applied in a more effective way, as well as allowing for additive manufacturing methods to be used—however, details regarding these aspects are beyond the scope of the current paper. By combining empirical formulas, computational fluid dynamics (CFD) analysis, and artificial neural networks (ANNs), the research focuses on achieving high efficiency and fast manufacturing. A series of geometries have been sized and validated using steady-state RANS (Reynolds Averaged Navier-Stokes) simulations, leading to the identification of the most efficient configuration. Subsequent optimization using an ANN resulted in a refined impeller design with notable improvements in hydraulic performance: a 3.55% increase in efficiency and a 7.9% increase in head. Key parameters influencing impeller performance, including blade number, incidence, and backsweep angles, are identified. This approach offers a comprehensive method to address the evolving requirements of space missions and contributes to the advancement of centrifugal pump technology in the space domain. Full article

This essay reads a short narrative, “Savoir” by Hélène Cixous, to describe susceptibility as a problem organized around two lines of impingement: between subject and world and between consciousness and the wayward impulses of interior life. The young girl in Cixous’s text suffers a moment of disorientation and distress one misty morning and, against presumptions of inviolability and ideals of subjective consistency, this unhappy event comes to resonate with her disappointed trust in the generosity of the world, her anxious sense of betrayal with respect to those who ought to protect her and her insecurity about her own role in this complex of associations. The frame of susceptibility thus opens up a space for Cixous’s reader and this essay to think the subject in her inconsistency and self-strangeness. Full article

Feminist reflections on the sexual division of labour have given rise to a body of knowledge on the ethics of care from different disciplines, including philosophy, in which outstanding contributions to the topic have been formulated. This approach is applicable to the analysis of any phenomenon and particularly that of disasters. As various investigations have highlighted, the consequences on the population throughout all of a disaster’s phases (prevention, emergency, and reconstruction) require an analysis of differentiated vulnerabilities based on gender and other identity categories, such as social class, ethnicity, age, disability, sexual identity, etc. The interrelation between all these variables gives rise to differentiated impacts that cannot be ignored in catastrophic contexts, where survival and sustaining life are at stake, so care becomes a central issue. Research on the topic has also identified that, along with the analysis of social vulnerability, we must consider the capacity for agency, both individual and collective, where care is once again of vital importance. Considering the gender approach and its multiple intersections is thus a fundamental theoretical-practical proposal for the study of disasters from philosophy, as it implies an unavoidable epistemic, ontological, and ethical reflection in the face of risk reduction. Full article

Watermelons are one of the most important crop species, and they are enjoyed across the globe; however, the cultivation of watermelon commercial varieties in arid regions is challenging, as they are highly susceptible to water deficit. Conversely, their wild relatives and traditional landraces have shown a higher tolerance to water deficit, which makes them important study material. Therefore, this study was undertaken to evaluate the potential roles of two compatible osmolytes (citrulline and arginine) in the tolerance of local watermelon accessions to drought stress. Four commonly cultivated watermelon accessions were used in this study to evaluate their response when exposed to water deficit stress. The accessions were planted in stress boxes in the greenhouse and allowed to grow until the fourth leaf was fully open and then the water deficit stress was initiated by withholding water for a period of nine days, before rewatering for three days. Data and leaf samples were collected at three-day intervals. The common drought indicators that were assessed, like chlorophyll fluorescence, showed that Clm-08 (wild watermelon) had significantly different results when compared to the other accessions; the Fv/Fm values for days 3, 6, and 9 were significantly higher than those of the other accessions, while phiNPQ was higher in the Clm-08 with average values of 0.41 and 0.41 on days 6 and 9 of the drought stress, respectively. This suggests that the wild watermelon responded differently to drought stress when compared with the other accessions. Arginine and citrulline are important osmolytes that play an important role in stress tolerance, and the results of the current study correlate with the common physiological indicators. The expression pattern for both the biochemical and molecular analyses of the two compatible osmolytes was higher in Clm-08 in comparison with that of the other accessions. The gene expressions of the enzymes in the citrulline and arginine pathways were higher in Clm-08; Cla022915 (CPS) recorded a 6-fold increase on day 6 and Cla002611 (ASS) recorded an 11-fold increase. This suggests that citrulline and arginine play an important role in watermelon tolerance to drought stress. Full article

The newly identified Sanghuangporus alpinus species of the Sanghuang mushroom genus has been found to possess significant medical benefits. However, the current artificial cultivation technology has not reached the requisite maturity. The response-surface methodology (RSM) was used to optimize the Sanghuangporus alpinus culture medium formulation and evaluate the functional activity of S. alpinus exopolysaccharides. First, a single-factor experiment was conducted to screen for optimal carbon and nitrogen sources for S. alpinus. Then, using Box–Behnken’s central composite design, a response-surface experiment was conducted to determine optimal culture parameters. Finally, the rationality of those parameters was assessed in a shaking flask experiment. The optimal culture parameters, determined through regression analysis, were 20.20 ± 0.17 g/L fructose (carbon source), 7.29 ± 0.10 g/L yeast extract (nitrogen source), and 0.99 ± 0.01 g/L dandelion. With optimization, the S. alpinus yield increased to 12.79 ± 1.41 g/L, twice that obtained from the initial culture medium. The S. alpinus exopolysaccharide exhibited an excellent antioxidant capacity, with the strongest scavenging effect noted on ABTS free radicals (lowest half-inhibitory concentration: 0.039 mg/mL). Additionally, this exopolysaccharide effectively inhibited various cancer cells, exhibiting the strongest activity against human glioma cells U251 (half-inhibitory concentration: 0.91 mg/mL). The RSM used to optimize the fermentation culture parameters of S. alpinus significantly increased the mycelial biomass. The improvement of Sanghuangporus alpinus yield through liquid fermentation and optimizing the fermentation medium could fill the existing gap in the cultivation of Sanghuangporus alpinus, as well as provide valuable data for the large-scale production of S. alpinus. Full article

The Sebou River Basin is vital for Moroccan agriculture, particularly in terms of producing industrial crops, fruits, vegetables, and olive oil. It is especially significant in viticulture, accounting for 80% and 60% of the national production area for wine and table grapes, respectively. However, the prevalence of diseases and pests requires extensive pesticide application in vineyards. This study aims to assess the impact of pesticides used in vineyards on the environment, human health and their associated sustainability. Agro-environmental indicators were evaluated across 30 vineyards covering 1197 hectares. Results show an average treatment frequency of 24.05 applications per growing cycle, the highest among grape-producing countries, with 77.94% being fungicides. The Quantity of Active Substances Indicator (QASI) reveals a high pesticide application rate of 44.60 Kg a.i./ha. Over 50% of chemicals are classified as “hazardous” based on the Environmental Impact Quotient (EIQ). A Pesticide Environmental Risk Indicator model (PERI) identifies three active ingredients with a high Environmental Risk Score (>5). Life Cycle Assessment (LCA) reveals that copper sulfate has significant environmental impacts compared to Mancozeb and sulfur. These findings highlight the extensive use of pesticides in vineyards, posing challenges to long-term sustainable agriculture due to associated environmental and health risks. Full article

Activated carbon (AC) serves as extensively researched adsorbents, with numerous established methods for their preparation. This study originated from the hypothesis that compressing a hydrocarbon substance to create a densely compacted pellet, known as pelletizing, would enhance the development of porous features of the resulting AC. The anticipated enhancement is attributed to the rise in spatial proximity amidst HEC polymer chains within the bulk of the pellet, which facilitates aromatization both in extent and functionality. 2-Hydroxyethyl cellulose (HEC) pellets were prepared by adjusting the duration of load holding, aiming to increase the packing density of HEC polymer chains via creeping. The BET analysis of the resulting AC samples demonstrates the efficacy of compression on HEC pellets in enhancing their porous properties. The FE-SEM study revealed diverse AC surface morphologies that are associated with a set of specific pelletizing conditions. The ¹³C NMR spectroscopy for carbon skeletons, FT-IR spectroscopy for organic functionality, and XPS spectroscopy for surface composition collectively report the leverage of compression treatment before pyrolyzing HEC pellets. Furthermore, the assessment of hydrogen sulfide adsorption by the resulting AC samples revealed distinctive breakthrough curves, providing validation for the proposed compression effect. Full article

Carbon-based materials have garnered significant attention since the groundbreaking synthesis of graphene. The exploration of novel 2D carbon allotropes has led to the discovery of materials with intrinsic properties distinct from graphene. Within this context, the biphenylene network (BPN) was successfully synthesized. In this study, we used molecular dynamics (MD) simulations with the Reactive Force Field (ReaxFF) to delve into the thermomechanical properties and fracture patterns of biphenylene-based nanotubes (BPN-NTs) exhibiting armchair (AC-BPN-NT) and zigzag (ZZ-BPN-NT) chiralities. Throughout the longitudinal deformation process, we observed significant morphological transformations preceding the structural fracture of the system. These transformations unfolded in distinct inelastic phases. In both cases, AC- and ZZ-BPN-NT, stress accumulation in four-membered rings led to the creation of octagonal structures; however, in AC, this occurs in the fracture region, subsequently causing the presence of nanopores. On the other hand, for ZZ-BPN-NT, stress accumulation in the rectangular rings occurred in bonds parallel to the deformation, with elongated octagonal structures. The Young’s modulus of these nanotubes ranged from 746 to 1259 GPa, with a melting point of around 4000 K. Our results also explore the influence of diameter and curvature, drawing comparisons with BPN monolayers. Full article

Introduction: Chronic wounds caused by diabetes or lower-extremity artery disease are intractable because the wound healing mechanism becomes ineffective due to the poor environment of the wound bed. Biosheets obtained using in-body tissue architecture (iBTA) are collagen-based membranous tissue created within the body and which autologously contain various growth factors and somatic stem cells including SSEA4-posituve cells. When applied to a wound, granulation formation can be promoted and epithelialization may even be achieved. Herein, we report our clinical treatment experience with seven cases of intractable diabetic foot ulcers. Cases: Seven patients, from 46 to 93 years old, had large foot ulcers including in the heel area, which were failing to heal with standard wound treatment. Methods: Two or four Biosheet-forming molds were embedded subcutaneously in the chest or abdomen, and after 3 to 6 weeks, the molds were removed. Biosheets that formed inside the mold were obtained and applied directly to the wound surface. Results: In all cases, there were no problems with the mold’s embedding and removal procedures, and Biosheets were formed without any infection or inflammation during the embedding period. The Biosheets were simply applied to the wounds, and in all cases they adhered within one week, did not fall off, and became integrated with the wound surface. Complete wound closure was achieved within 8 weeks in two cases and within 5 months in two cases. One patient was lost due to infective endocarditis from septic colitis. One case required lower leg amputation due to wound recurrence, and one case achieved wound reduction and wound healing in approximately 9 months. Conclusions: Biotubes obtained via iBTA promoted wound healing and were extremely useful for intractable diabetic foot ulcers involving the heel area. Full article

Spinal cord injury (SCI) represents a severe trauma to the nervous system, leading to significant neurological damage, chronic inflammation, and persistent neuropathic pain. Current treatments, including pharmacotherapy, immobilization, physical therapy, and surgical interventions, often fall short in fully addressing the underlying pathophysiology and resultant disabilities. Emerging research in the field of regenerative medicine has introduced innovative approaches such as autologous orthobiologic therapies, with bone marrow aspirate (BMA) being particularly notable for its regenerative and anti-inflammatory properties. This review focuses on the potential of BMA to modulate inflammatory pathways, enhance tissue regeneration, and restore neurological function disrupted by SCI. We hypothesize that BMA’s bioactive components may stimulate reparative processes at the cellular level, particularly when applied at strategic sites like the sacral hiatus to influence lumbar centers and higher neurological structures. By exploring the mechanisms through which BMA influences spinal repair, this review aims to establish a foundation for its application in clinical settings, potentially offering a transformative approach to SCI management that extends beyond symptomatic relief to promoting functional recovery. Full article

Recognizing the growing interests and benefits of technology-assisted interactive telerehabilitation in various populations, the aim of this review is to systematically review the effects of interactive telerehabilitation with remote monitoring and guidance for improving balance and gait performance in older adults and individuals with neurological conditions. The study protocol for this systematic review was registered with the international prospective register of systematic reviews (PROSPERO) with the unique identifier CRD42024509646. Studies written in English published from January 2014 to February 2024 in Web of Science, Pubmed, Scopus, and Google Scholar were examined. Of the 247 identified, 17 were selected after initial and eligibility screening, and their methodological quality was assessed with the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-sectional Studies. All 17 studies demonstrated balance and gait performance improvement in older adults and in individuals with stroke, Parkinson’s disease, and multiple sclerosis following 4 or more weeks of interactive telerehabilitation via virtual reality, smartphone or tablet apps, or videoconferencing. The findings of this systematic review can inform the future design and implementation of interactive telerehabilitation technology and improve balance and gait training exercise regimens for older adults and individuals with neurological conditions. Full article

Background: The Clustered Orienteering Problem is an optimization problem faced in last-mile logistics. The aim is, given an available time window, to visit vertices and to collect as much profit as possible in the given time. The vertices to visit have to be selected among a set of service requests. In particular, the vertices belong to clusters, the profits are associated with clusters, and the price relative to a cluster is collected only if all the vertices of a cluster are visited. Any solving methods providing better solutions also imply a new step towards sustainable logistics since companies can rely on more efficient delivery patterns, which, in turn, are associated with an improved urban environment with benefits both to the population and the administration thanks to an optimized and controlled last-mile delivery flow. Methods: In this paper, we propose a constraint programming model for the problem, and we empirically evaluate the potential of the new model by solving it with out-of-the-box software. Results: The results indicate that, when compared to the exact methods currently available in the literature, the new approach proposed stands out. Moreover, when comparing the quality of the heuristic solutions retrieved by the new model with those found by tailored methods, a good performance can be observed. In more detail, many new best-known upper bounds for the cost of the optimal solutions are reported, and several instances are solved to optimality for the first time. Conclusions: The paper provides a new practical and easy-to-implement tool to effectively deal with an optimization problem commonly faced in last-mile logistics. Full article

In this paper, we present the synthesis and luminescent spectra of rare-earth (RE)-doped aluminum and lanthanum borates intended to serve as narrow excitation–emission band fluorescent markers. We perform a detailed 3D excitation–emission matrix (EEM) analysis of their spectra, compare the measurements from both standard and mobile phone spectrometers, and outline the basic differences and advantages of each method. While smartphones have a different and non-uniform spectral response compared to standard spectrometers, it is shown that they offer a number of advantages such as contactless interrogation, efficient suppression of the UV excitation light, and simultaneous spectral analysis of spatially arranged arrays of fluorescent markers. The basic emission peaks have been observed and their corresponding electronic transitions identified. The obtained results show that the rare-earth-doped La and Al borates feature excitation–emission bandwidths as low 15 nm/12 nm, which makes them particularly appropriate for use as luminescent markers with UV LED excitation and smartphone interrogation. Full article

The traditional single-mode fiber (SMF) optical time domain reflectometer (OTDR) may not be able to accurately detect and locate fault events in the dead zone of few-mode fiber (FMF) links. This paper introduces the concept of higher-order spatial mode detection dimensions unique to FMF, combined with the spatial mode coupling characteristics between modes. The Fresnel reflection from the end face of the fiber, the interior of the circulator, and the connector only occurs in the spatial mode of the injected optical pulse. The Rayleigh backscattering, which reflects the fault distribution characteristics of FMF links, can be detected by non-excited higher-order spatial modes. The proposed method can completely overcome the traditional OTDR dead zone. In this paper, the six-mode fiber is taken as an example for experimental verification. The detection optical pulse is injected into the fundamental mode LP₀₁, and the Rayleigh backscattering of LP_11a, LP_11b, LP_21a, LP_21b, and LP₀₂ higher-order spatial mode are collected and analyzed to accurately detect and locate the fusion splice fault event at 100 m and 500 m in the dead zone. Full article