Search Results (272)

In this paper, we propose and experimentally demonstrate a dual-parameter fiber optic sensor, which combines a Fabry–Perot interferometer (FPI) and a Mach–Zehnder interferometer (MZI) for simultaneous pressure and temperature sensing. The Fabry–Perot (FP) cavity is formed by sandwiching a capillary fiber between a single-mode fiber and a dual-core fiber (DCF). A fluid channel is very close to the central core of the DCF. By precisely drilling micro-air chambers in the annular cladding of a capillary fiber (CF) using a femtosecond laser, external air pressure can directly affect the capillary fiber and induce changes in the refractive index of the air in the CF. The F-P cavity achieves a pressure sensitivity of 3.67 nm/MPa with a temperature cross-sensitivity of 2.82 pm/°C. The MZI is constructed using a dual-core fiber filled with silicone oil in the fluidic channel, which enhances temperature sensitivity through the thermo-optic effect. The MZI sensor exhibits a nonlinear temperature response with an average sensitivity of 103.43 pm/°C. The corresponding pressure cross-sensitivity is about –0.11 nm/MPa. Due to very low cross-sensitivity, simultaneous measurement of temperature and gas pressure is feasible. In addition, we implement a variant by replacing silicone oil with a UV-curable adhesive, which delivers a comparable FP-based pressure sensitivity of ~3.93 nm/MPa while yielding an MZI-based temperature sensitivity of 71.7 pm/°C and potentially improved long-term stability. Full article

The Fabry–Pérot interferometer (FPI) structure has been designed and fabricated through the heterogeneous splicing of single-mode fiber to hollow-core fiber, coupled with precision length cutting. Humidity sensitive materials of polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), and polyethylene glycol (PEG) film have been elaborated via a dip-coating and withdrawal technique, enabling the development of three distinct FPI-based fiber optic humidity sensors. Experimental data revealed that the PMMA-coated FPI sensor demonstrated the lowest sensitivity to humidity variations, while the PEG-functionalized FPI exhibited a sensitivity approximately an order of magnitude higher than that of PMMA. The proposed fiber optic humidity probe features a compact design, simplified fabrication workflow, and robust compatibility with spatially restricted, integration-demanding, or electrically hostile environments unsuitable for conventional sensor deployment. Full article

Albendazole (ABZ) is a broad-spectrum anthelmintic drug whose residual presence in food and the environment raises public health concerns, requiring rapid and sensitive methods of detection. In this work, a sensitive Fabry–Pérot interferometer (FPI) probe was fabricated by realizing a cavity located at the tip of a single-mode optical fiber core with a molecularly imprinted polymer (MIP) for ABZ detection. The fabrication process involved the development of a photoresist-based micro-hole filled by the specific MIP via thermal polymerization. Interferometric measurements obtained using the proposed sensor system have demonstrated a limit of detection (LOD) of 27 nM, a dynamic concentration range spanning from 27 nM (LOD) to 250 nM, and a linear response at the nanomolar level (27 nM–100 nM). The selectivity test demonstrated no signal when interfering molecules were present, and the application of the sensor for ABZ quantification in a commercial pharmaceutical sample provided good recovery, in accordance with bioanalytical validation standard methods. These results demonstrate the capability of a MIP layer-based FPI probe to provide low-cost and selective optical-sensing strategies, proposing a competitive approach to traditional analytical techniques for ABZ monitoring. Full article

This paper presents a high-sensitivity multi-point seawater temperature detection system based on the virtual Vernier effect, achieved through multiplexed Fabry–Perot (FP) cavities combined with optical frequency-modulated continuous wave (FMCW) interferometry. To address the nonlinear frequency scanning issue inherent in FMCW systems, this paper implemented a software compensation method. This approach enables accurate positioning of multiple FP sub-sensors and effective demodulation of the sensing interference spectrum (SIS) for each FP interferometer (FPI). Through digital signal processing (DSP) algorithms and spectral demodulation, each sub-FP sensor generates an artificial reference spectrum (ARS). The virtual Vernier effect is then achieved by means of a computational process that combines the SIS intensity with the corresponding ARS intensity. This eliminates the need for physical reference arrays with carefully detuned spatial frequencies, as is required in traditional Vernier effect implementations. The sensitivity amplification can be dynamically adjusted with the modulation function parameters. Experimental results demonstrate that an optical fiber link of 82.3 m was achieved with a high spatial resolution of 23.9 $\mathsf{\mu }\mathrm{m}$. Within the temperature range of ${30 }^{\circ }\mathrm{C}$ to ${70 }^{\circ }\mathrm{C}$, the temperature sensitivities of the three enhanced EIS reached −275.56 $\mathrm{pm}{/}^{\circ }\mathrm{C}$, −269.78 $\mathrm{pm}{/}^{\circ }\mathrm{C}$, and −280.67 $\mathrm{pm}{/}^{\circ }\mathrm{C}$, respectively, representing amplification factors of 3.32, 4.93, and 6.13 compared to a single SIS. The presented approach not only enables effective multiplexing and spatial localization of multiple fiber sensors but also successfully amplifies weak signal detection. This breakthrough provides crucial technical support for implementing quasi-distributed optical sensitization sensing in marine environments, opening new possibilities for high-precision oceanographic monitoring. Full article

In the field of life sciences, delay effects are often modeled with two compartments that do not model any particular organ. In this paper the use of this double counterpart model is investigated in Fixed-Point Iteration-based (FPI) Control, which was introduced in 2009 as an adaptive extension to the Computed Torque Control method. This controller is particularly sensitive to delays and measurement noise due to its iterative nature. It was recognized that, besides modeling the delay effect, this signal tackling also provided the controller with some noise filtering ability; the formerly accumulated effects of noise filtering and formally delayed sampling were avoided. This smeared delay has a noticeable effect even slightly later in time, making the adaptive method based on it more robust. This assumption was investigated both on a simulation and experimental basis. Full article

Aim: The aim of the study was to synthesize validated patient-reported outcome measures (PROMs) for assessing health-related quality of life (HRQoL) in women with endometriosis and to outline their clinical implications. Methods: We conducted a narrative review of English-language literature indexed in PubMed, Scopus, Web of Science, and Cochrane Library, covering the period 2014–2024, with earlier seminal studies included where relevant. We focused on validated PROMs for QoL but also considered standardized tools such as the Endometriosis Fertility Index (EFI), rASRM, and #Enzian classifications, given their role in clinical interpretation and counseling. Findings: Generic instruments (SF-36, WHOQOL-BREF, EQ-5D), disease-specific tools (EHP-30, EHP-5), and fertility-related questionnaires (FertiQoL, FPI) have demonstrated validity and responsiveness; however, these are inconsistently applied in practice. Knowledge gaps remain regarding routine implementation, timing, and frequency of assessment, and integration with clinical staging or fertility indices (e.g., EFI). Global frameworks such as the WERF EPHect platform facilitate standardized clinical and surgical data capture, though their use is primarily in research rather than routine care. Conclusions: We recommend combining a disease-specific PROM (EHP-30/EHP-5) with a generic instrument (SF-36 or EQ-5D) and adding FertiQoL when fertility is relevant. PROMs should be collected longitudinally (baseline, post-intervention, follow-up) and interpreted alongside clinical context, including pain phenotype, surgical staging (#Enzian/rASRM), and fertility goals. Embedding PROMs into multidisciplinary pathways enables shared decision-making, individualized treatment planning, and improved comparability of patient-centered outcomes. Full article

Background: Recreational running is a globally popular activity known for its physical and mental health benefits, including stress reduction and improved quality of life. However, many recreational runners lack structured guidance, increasing their risk of lower limb injuries, often linked to variations in foot posture. Although African populations are well known for their endurance running abilities, limited research has examined their foot biomechanics and injury risk. This study addresses this gap by investigating foot posture and structure among African male recreational runners in South Africa. Methods: A cross-sectional, quantitative design was employed. Data were collected using structured data collection sheets, capturing demographic information, Foot Posture Index (FPI) scores, and Three-Dimensional (3D) foot scans. FPI provided a clinical evaluation of foot posture, while 3D foot scans delivered precise structural measurements. The aim was to describe and compare the foot posture characteristics and bilateral load distribution patterns in this population, using the Foot Posture Index (FPI) and 3D foot scanning as complementary assessment tools. Results: Findings showed agreement between FPI and 3D foot scan results, with both tools identifying a high prevalence of flexible flat feet among participants. Each method captured unique aspects of foot posture: FPI offered a qualitative overview, while 3D scans provided detailed, quantitative insights. This dual-assessment approach supports the value of using complementary methods in clinical and sports settings. Conclusions: This study suggests that integrating FPI and 3D scanning enhances the accuracy of foot posture assessments. Despite limitations such as a moderate sample size, the findings support personalized clinical interventions and footwear design tailored to the unique biomechanics of Black African male runners. Full article

Background: Recently, elite women’s boxing has undergone significant structural and regulatory changes, including the adoption of the 3 × 3-min-bout format and expanded Olympic categories. Despite increased female participation, scientific literature remains predominantly focused on male athletes. This study aimed to identify the technical and tactical actions that distinguish winner from loser boxers in elite amateur women’s boxing by analysing the final matches of the 2023 IBA Women’s World Boxing Championships. Methods: Twelve final bouts (one per weight-category) were analysed using a customised notational framework based on the offensive–defensive interaction cycle. A total of 1323 offensive and 1456 defensive actions were recorded and categorised using Kinovea (0.9.5 release) software and an Excel dashboard. Offensive Effectiveness Ratio (OER) and Defensive Effectiveness Ratio (DER) were calculated, and Chi-square tests with standardised residuals were applied to detect associations between action types and bout outcomes. Results: Winners performed fewer offensive actions (n = 635) than losers (n = 688) but demonstrated significantly higher OER across all rounds (W: 0.39-0.38-0.39; L: 0.26-0.28-0.29). Winners landed more punches to the head and made greater use of rear-hand hooks and uppercuts. Pivoting and shifting back, particularly when followed by counterattacks, were significantly associated with winners (p < 0.001). Conversely, parrying and single counterpunches were linked to losing outcomes. DER values suggested superior defensive efficiency among winners. Conclusions: Winner boxers showed superior technical effectiveness, selective use of single and rear-hand punches and used more dynamic defensive strategies. These findings support using notational analysis in high-performance coaching and emphasise the need for more research on elite female combat athletes. Full article

Multidrug-resistant (MDR) Shiga toxin-producing Escherichia coli O157 (STEC O157) is a public health threat. This study analyzed publicly available surveillance data collected by the National Antimicrobial Resistance Monitoring System (NARMS) to assess temporal and regional differences and co-resistance patterns in MDR STEC O157 human clinical isolates across the United States. Co-resistance patterns were assessed by hierarchical clustering and Phi coefficient network analyses. A negative binomial regression model estimated the incidence rate ratios (IRRs) for the number of antimicrobial classes to which an isolate was resistant, across years and geographic regions. Out of 1955 isolates, 151 (7.57%) were MDR. The most important clusters were Cluster 1 (n = 1632), which included susceptible isolates, and Cluster 3 (n = 255), comprising the majority of the MDR isolates, having a high resistance prevalence to tetracyclines (TET) (0.97), folate pathway inhibitors (FPI) (0.77), and phenicols (PHN) (0.49). In the co-resistance network, TET, FPI, and PHN served as central hubs, with large nodes and thick edges, suggesting that they are frequently co-selected. The highest IRRs were observed in Regions 6 (IRR = 2.72) and 9 (IRR = 2.00), compared to Region 4. Compared to 2010, a significant increase in the IRR was observed in each year from 2015 to 2021 (IRRs 2.5–4.38). Antimicrobial stewardship programs and public health interventions targeting MDR E. coli O157 are needed to mitigate the emergence of antimicrobial resistance. Full article

The operational performance of Flexible Hinge Piezoelectric Stages (FHPSs), essential components in precision engineering, is fundamentally constrained by the inherent hysteresis of the piezoelectric actuator (PEA). A significant deficiency in prevailing characterization methods is their failure to consider the dynamic nature of the mechanical preload exerted by the flexible hinge. This position-dependent preload induces substantial deviations in the PEA’s response characteristics, thereby compromising the predictive accuracy of conventional design frameworks. To address this limitation, this paper proposes a Force-Dependent Prandtl–Ishlinskii (FPI) model that explicitly formulates the PEA’s hysteretic behavior as a function of variable preload conditions. The FPI model is subsequently integrated into a comprehensive FPI-FFEM characterization framework. Within this framework, a Force-analyzed Finite Element Method (FFEM) is utilized to compute the dynamic preload throughout the actuator’s operational stroke. This information, notably neglected in conventional FEM analysis, is essential to the fidelity of the proposed FPI model. Experimental validation demonstrates the superior fidelity of the FPI model in comparison to the traditional PI model for tracking preload-induced nonlinearities. Furthermore, the complete FPI-FFEM framework exhibits substantially enhanced prediction accuracy relative to both conventional PI-FEM and advanced LDPI-FEM methodologies, as demonstrated by a significant reduction in the Mean Absolute Error (MAE). Full article

The rising prevalence of pediatric food allergies represents a growing public health concern, with hospitalizations for food-induced anaphylaxis on the rise. Early cutaneous manifestations, particularly in the setting of atopic dermatitis (AD), may indicate sensitization via the skin—a critical route for allergen exposure in early life. Pediatric food allergies can be IgE-mediated, non-IgE-mediated, or mixed, with each type presenting distinct pathophysiological and clinical features. IgE-mediated reactions often involve acute urticaria and angioedema, while non-IgE forms, such as food protein-induced enterocolitis syndrome (FPIES), manifest with delayed gastrointestinal symptoms and limited skin involvement. AD is closely linked with food allergies, both in pathogenesis and symptom exacerbation, with a high prevalence of co-occurrence. Diagnosis primarily relies on clinical evaluation, supported by testing such as skin prick testing, serum IgE, and oral food challenges, though limitations exist in sensitivity and specificity. Management emphasizes allergen avoidance, symptom control, and multidisciplinary care. While many pediatric food allergies resolve with age, others persist or present chronically, necessitating long-term strategies. Coordinated management between allergy and dermatology is key to minimizing complications and supporting better long-term outcomes for affected children. Full article

Background/Objectives: Food protein-induced enterocolitis syndrome (FPIES) is a food-related hypersensitivity disorder characterized by delayed repeated vomiting that typically presents within the first years of life. Although FPIES has traditionally been considered a pediatric condition, it has more recently been observed also in teenagers and adults. Adult FPIES may be a continuation of childhood-onset disease or new-onset forms developing later in life. This review aims to describe the peculiarities of FPIES across the lifespan and to provide an update from the last years on the studies focused on FPIES in adolescence. Methods: Papers focusing on FPIES in adolescents, in English and published in PubMed, were reviewed. Results: There is less data available in the literature on FPIES in adolescents. Multiple sensitizations to food can compromise nutritional status in patients with FPIES. Several potential diagnostic biomarkers related to genomic susceptibility, altered immunologic response, mucosal inflammation and intestinal microbiota are under study/validation. The lack of age-specific diagnostic algorithms makes it difficult to understand the clinical features of persistent forms of FPIES. Conclusions: Shared transition medicine protocols tailored to adolescents could help us better understand the clinical, pathophysiological, diagnostic, and therapeutic characteristics of this delicate phase of life. Full article

A highly sensitive Fabry–Pérot interferometer (FPI) is fabricated via symmetric taper fiber cleaving and centered waist-inserted assembly, a design where geometric symmetry is fundamental to the sensor’s performance. The FPI is fabricated by simple and cost-effective techniques, including fiber cleaving, splicing, and tapering. Due to the ultra-long cantilever beam with an effective length of 2.33 mm and the ultra-short Fabry–Pérot (FP) cavity with an actual length of 13.98 μm, the sensor exhibits an ultra-high strain sensitivity of 544.57 pm/με in experimental results. The sensor boasts a small temperature sensitivity of 1.02 pm/°C and a cross-temperature sensitivity of 0.0019 µε/°C in the temperature range of 25–200 °C. Furthermore, the sensor has good stability and repeatability. Owing to the symmetry-enhanced design, simple fabrication process, high strain sensitivity, as well as a stable, linearly proportional response over an extensive strain regime, the device has large potential in various sensing applications. Full article

An optical fiber force sensor based on the Vernier effect in cascaded Fabry–Perot interferometers (FPIs) formed by a barium tantalate microsphere and a section of polymethyl methacrylate (PMMA) optical fiber is proposed and investigated. Optical fiber sensors offer numerous advantages over their electronic counterparts, including immunity to electromagnetic interference and suitability for harsh environments. Despite these benefits, current optical fiber force sensors often face limitations in sensitivity, reliability, and fabrication costs. The proposed sensor has the potential to address these issues. Simulations and experimental results demonstrate that the sensor achieves a sensitivity of 9279.66 nm/N in a range of up to 3 mN. The sensor also exhibits excellent repeatability, making it a promising candidate for high-performance force monitoring in various challenging environments. Full article

Background: Pes planus is a condition where the arch of the foot collapses, resulting in the entire sole contacting the ground. The biomechanical implications of pes planus on gait have been widely studied; however, research specific to Black African populations, particularly recreational runners, is scarce. Aim: This study aimed to describe the forefoot centre of pressure (CoP) trajectory during the barefoot gait cycle among Black African recreational runners with pes planus. Methods: A prospective explorative and quantitative study design was employed. Participants included Black African male recreational runners aged 18 to 45 years diagnosed with pes planus. A Freemed™ 6050 force plate was used to collect gait data. Statistical analysis included cross-tabulations to identify patterns. Results: This study included 104 male participants across seven weight categories, with the majority in the 70-to-79 kg range (34.6%, n = 36). Most participants with pes planus showed a neutral foot posture (74.0%, n = 77) on the foot posture index 6 (FPI-6) scale. Flexible pes planus (94.2%, n = 98) was much more common than rigid pes planus (5.8%, n = 6). Lateral displacement of the CoP was observed in the right forefoot (90.4%, n = 94) and left forefoot (57.7%, n = 60). Load distribution patterns differed between feet, with the right foot favouring the medial heel, arch, and metatarsal heads, while the left foot favoured the lateral heel, medial heel, and lateral arch. No statistical significance was found in the cross-tabulations, but notable lateral CoP displacement in the forefoot was observed. Conclusions: The findings challenge the traditional view of pes planus causing overpronation and highlight the need for clinicians to reconsider standard diagnostic and management approaches. Further research is needed to explore the implications of these findings for injury prevention and management in this population. Full article