Search Results (2,442)

ZBLAN (ZrF₄-BaF₂-LaF₃-AlF₃-NaF) fluoride glass is a promising infrared optical fiber material because of its wide transmission window and low theoretical attenuation; however, unwanted crystallization during thermal processing can introduce scattering centers and degrade optical performance. Previous studies have mainly focused on temperature effects and microgravity-based crystallization suppression, while the role of mechanical vibration remains insufficiently understood. This study addresses this gap by investigating how controlled mechanical vibration influences crystallization onset, morphology, and structural evolution in ZBLAN glass during short-duration thermal treatment. ZBLAN samples were treated at selected temperatures with and without vibration using a custom heating–vibration apparatus and characterized by optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray diffraction (XRD). Temperature-only treatment produced a gradual transition from transparent amorphous glass to crystallized structures with increasing temperature. Vibration-assisted treatment altered crystallization behavior, producing distinct needle-like, bow-tie, and feather-like morphologies depending on temperature and vibration intensity. AFM confirmed a significant increase in surface roughness, while XRD verified structural evolution from amorphous to highly crystallized states. At higher vibration levels, irregular crystallization suggested that excessive sample movement may reduce thermal contact and change the effective heating condition. These findings demonstrate that mechanical vibration is a critical and controllable processing variable in ZBLAN fabrication and should be carefully managed to suppress unwanted crystallization in both terrestrial and space-based fiber manufacturing. Full article

Background: Public fitness facilities are high-contact environments that facilitate microbial transfer via shared surfaces; however, temporal dynamics and device-specific contamination patterns remain insufficiently characterized. Methods: A repeated-measures observational study was conducted in a fitness facility over five consecutive weekdays (Monday to Friday). A total of 180 surface samples were collected from 12 gym devices, each sampled three times daily (morning, noon, and evening). Surface-associated cultivable bacteria were recovered using culture-based methods followed by MALDI-TOF MS identification. Ecological metrics, including species richness and Shannon diversity, were calculated, and taxa were classified by origin (skin-associated versus environmental). Device-specific contamination profiles were developed using a composite index incorporating pathogen presence, contamination frequency, and persistence. Temporal trends and predictors of contamination were analyzed using mixed-effects regression models. All statistical analyses were performed in R. Results: A total of 248 bacterial isolates were identified, representing 61 species across 32 families, with a predominance of skin-associated taxa (72.2%). Sampling time point was a strong independent predictor of contamination (adjusted OR for noon vs. morning: 7.19; p < 0.001). While overall microbial diversity remained stable across devices (Shannon index, p = 0.44), substantial heterogeneity was observed in pathogen prevalence, multispecies burden, and persistence. The functional trainer and leg extension showed the highest composite risk scores (42.3%), while the ab crunch machine and upper body ergometer demonstrated significantly increasing contamination trends over the sampling period (p < 0.05). Co-occurrence analysis showed nonrandom microbial associations, with the strongest positive links between Micrococcus luteus and Staphylococcus saprophyticus (Φ = 0.76) and Staphylococcus aureus (Φ = 0.61). Conclusions: Gym equipment surfaces harbor predominantly human-associated microbial communities exhibiting dynamic temporal contamination patterns, and on selected devices, increasing the baseline contamination across consecutive cleaning cycles. The findings indicate that contamination patterns on shared fitness equipment are dominated by taxa commonly associated with human skin and support targeted hygiene interventions focused on frequently contacted devices and periods of elevated contamination. Full article

Space debris mitigation is a pivotal endeavor essential for sustaining human space exploration. To address the challenges posed by irregularly shaped, variably sized, and dynamically unpredictable debris in orbit, this paper proposes a mechanical design and motion control strategy for an omniwheel-based driving system. The mechanical architecture and kinematic principles of the system are elaborated in detail, complemented by the formulation of tailored motion control algorithms. First, the fundamental architecture of the driving subsystem is introduced, and the linear mapping between the uniformly distributed triad of omniwheels and the spherical drive is derived. Building upon this foundation, the kinematic transmission from the three evenly spaced driving subsystems to the contact sphere is established. This leads to the derivation of the overall linear mapping relationship between the nine uniformly distributed omniwheels and the contact sphere’s motion, thereby enabling precise trajectory tracking of the contact sphere via omniwheel actuation. Finally, comprehensive experimental validation was conducted in two phases. The first phase evaluated the fidelity and stability of the driving subsystem’s simulation model, as well as the accuracy of the kinematic mapping. Results demonstrate that the simulation model is highly stable and reliable. Under identical desired trajectories, the Root Mean Square Error (RMSE) between theoretical calculations and simulations was 4.082 × 10⁻⁴, while the RMSE between theory and physical prototypes was 0.0032. These results confirm that the motion errors remain within acceptable tolerances and the kinematic mapping is accurate. For the spherical end-effector, under the same trajectory conditions, the RMSE values among theoretical calculations, simulations, and physical prototypes were 0.0929 and 1.62, respectively. These findings validate the derived linear kinematic mapping, demonstrating its efficacy in precise motion control, which lays the foundation for future on-orbit detumbling tasks. Full article

Cow-based calf rearing (dam- or foster cow-based) is gaining popularity as a relatively natural husbandry practice. However, direct udder contact by calves creates a bidirectional transmission route for pathogens. The objective of this cross-sectional study was to investigate the prevalence and concordance of mastitis-associated pathogens in the milk of cows and the saliva of corresponding calves at the time of weaning. On 15 organic dairy farms, milk samples from 269 cows and saliva samples from 403 calves were collected at weaning. Pathogen differentiation was performed via Matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF), and strain typing was additionally conducted via randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Dominant pathogens in milk were Non-aureus-Staphylococci (NaS)/Mammaliicoccus spp. and Corynebacterium spp., and in calf saliva, NaS/Mammaliicoccus spp. (primarily M. sciuri, S. xylosus). There were a total of 12 strain concordances, exclusively in foster cow–calf pairs (Fisher’s exact test, p = 0.012). The highest observed/expected ratio was found for P. multocida (21.1). For S. aureus, strain matches were found in 3 foster cow–calf pairs across 2 farms. Direct strain concordance was generally observed rather rarely. The observed strain concordances suggest transmission between cows and calves, particularly for S. aureus and P. multocida. NaS and Mammaliicoccus spp. concordances are likely attributable to a common environmental source. Full article

Purpose—The flexspline of a harmonic drive constitutes a thin-walled structure with discontinuous gear rim and cylinder configuration, where cyclic stresses induce stress concentration, followed by crack initiation, propagation, and ultimately fatigue failure. This paper reviews advancements in understanding its mechanical properties and fatigue failure mechanisms, aiming to establish a foundation for enhancing operational longevity and guiding future research. Design/Methodology/Approach—The study integrates meshing theory, tooth shape parameters, cylinder stress influencers, and assembly/meshing stress considerations. Theoretical analysis, finite element simulations, and experimental methods are employed to examine stress patterns and fatigue dynamics. Structural parameters and tooth profiles are systematically analyzed for their impact on stress distribution and fatigue life. Findings—Flexspline fatigue failure arises from tooth root stress concentration and cylinder bending stress accumulation. The double-circular-arc tooth profile boosts load capacity by 35% relative to the involute profile, yet demands high-precision machining to preserve meshing performance. Increasing cylinder length mitigates stress concentration but reduces torsional stiffness, while optimized root fillet radii can lower the stress concentration coefficient by 28%. Assembly interference and meshing contact stress accelerate crack initiation, as validated by transient dynamics simulations. Surface strengthening processes (e.g., shot peening) enhance fatigue life by up to 66% through residual compressive stress regulation. Originality/Value—This paper synthesizes multi-scale research on flexspline design, structural optimization, and fatigue mechanisms, proposing novel approaches such as “manufacturability-oriented optimization” and digital twin-driven monitoring. By linking dynamic loads, material properties, and geometric parameters, it bridges theoretical gaps and provides actionable insights for high-precision harmonic drives in robotics and aerospace, advancing reliability in precision transmission systems. Full article

Finite element modeling is central to the safety assessment and structural health monitoring of transmission towers, yet conventional workflows remain labor-intensive and depend on complete engineering drawings, which are often unavailable for aging towers. This study proposes an automated finite element modeling framework based on unmanned aerial vehicle (UAV) point clouds. Multi-view stereo reconstruction with geometric–photometric depth refinement is used to generate dense three-dimensional point clouds, from which key nodal coordinates are extracted and converted into executable ANSYS APDL command streams. Material properties, boundary conditions, and loads are then assigned automatically to construct computable finite element models. This method was first validated using concrete cubes and Q235B steel members and was further evaluated on a scaled transmission tower through comparison with the commercial SmartTower workflow. The results show that the proposed approach reduces modeling time from 1.5 days to 4.3 h, corresponding to an 88% efficiency improvement, while keeping nodal coordinate errors within 10% and modal frequency errors within 3.7%. The framework satisfies the basic requirements of transmission tower numerical analysis and provides a practical non-contact solution for the rapid assessment of aging towers lacking design documentation. Full article

In this study, the valorization of poly(lactic acid) (PLA) waste as well as rice husk into sustainable materials was explored. To simulate the industrial valorization of defective PLA parts, scraps and burrs, PLA was reprocessed (rPLA) by melt extrusion and further plasticized with 15 wt.% of acetyl tributyl citrate (ATBC) and reinforced with rice husk (RH) or rice husk biochar (RHB) in 1 or 3 wt.%. The melt flow index was determined to assess the effect of reprocessing and the addition of RH or RHB on the material degradation. The obtained films were characterized in terms of their structural, mechanical, and thermal behavior. The water-related behavior of the materials was evaluated by measuring the static water contact angle and the water vapor transmission rate (WVTR). Compostability was proposed as an end-of-life option, therefore disintegration under composting conditions was assessed. Reprocessing increased the MFI and slightly reduced the strength and the modulus, consistent with chain scission. ATBC facilitated the processability, improved the particles’ dispersion and provided ductility to the final materials. RH and RHB acted mainly as nucleating agents and strongly modified the surface wettability. A low RHB loading improved the WVTR, whereas a higher filler content and ATBC generally increased the WVTR. All the films were completely disintegrated within 18 to 21 days. These results show practical valorization routes to obtain rPLA films with tunable properties and to preserve the inherent composting disintegration of PLA. Full article

The pantograph–catenary system (PCS) is a critical component through which electrified railway trains obtain electrical energy, and the current-carrying friction and wear behavior at the pantograph–catenary interface directly affect current collection quality and operational safety. Water environments, particularly icing conditions, may induce contact instability, arc ablation, and abnormal wear. Therefore, this paper provides a comprehensive review of research progress on the current-carrying friction and wear behavior of C/Cu contact pairs under water environments. It focuses on the interfacial evolution characteristics under three different phase states of water and analyzes their influence mechanisms on lubrication conditions, current transmission, and wear behavior. Typical protection strategies, including speed restriction, mechanical de-icing, thermal de-icing, and anti-icing measures, are summarized, and their applicability and current development status are discussed. Finally, it is suggested that future research should focus on the development of high-performance carbon strip materials, accurate monitoring of ice morphology and types, and efficient hybrid anti-/de-icing technologies, thereby ensuring the reliable operation of high-speed railways under icing conditions. Full article

Climate change is reshaping the epidemiology of vector-borne diseases in Europe by altering the ecological conditions that determine vector survival, seasonal activity and pathogen transmission. Rising temperatures, milder winters, prolonged warm seasons and changing precipitation patterns are increasing the suitability of parts of Europe for competent mosquito, tick and sandfly vectors. These changes, combined with human mobility and land-use change, increase the probability that imported pathogens encounter permissive conditions for local transmission. This Opinion article examines autochthonous vector-borne disease transmission in Europe, using dengue as a sentinel example of a wider climate-sensitive transition. We discuss how imported viraemic cases, established competent vectors, vector–host contact and delayed clinical recognition can converge to enable local outbreaks. Beyond dengue, we consider West Nile virus, chikungunya, tick-borne encephalitis, leishmaniasis and Crimean–Congo haemorrhagic fever as examples of a broader and increasingly heterogeneous European risk landscape. We argue that the public-health impact of this transition is shaped not only by vector expansion, but also by gaps in surveillance integration, diagnostic readiness, workforce preparedness and One Health coordination. Strengthening climate-informed surveillance, rapid laboratory capacity, frontline clinical awareness and cross-sectoral response systems will be essential to prevent repeated introductions from becoming sustained public-health challenges. Full article

Cystic echinococcosis (CE), a neglected zoonotic disease caused by Echinococcus granulosus sensu lato, poses a persistent public health burden in agro-pastoral regions worldwide. This study provides a large-scale epidemiological assessment of CE, highlighting sustained zoonotic transmission driven by agro-pastoral practices and human–animal interactions, and supporting the urgent implementation of One Health strategies. This ten-year retrospective study (2015–2024) analyzed 326 surgically confirmed cases from five hospitals in Djelfa. The cumulative surgical incidence was 2.04 cases per 100,000 person-years, classifying the region as hypoendemic. Females predominated (61.96%), and individuals aged 31–60 years represented 47.24% of cases. Rural residence (73.62%) and dog contact (94.17%) were major risk factors, with hepatic localization dominating (88.96%). Correlation analysis showed moderate associations between rural habitat and dog contact (V = 0.46, p < 0.001) and between sex and habitat (V = 0.34, p < 0.001), as well as weaker but significant associations for age and cyst location (V = 0.28, p < 0.001) and dog contact and cyst location (V = 0.20, p < 0.05). No postoperative mortality was recorded. These findings confirm active transmission linked to agro-pastoral practices and emphasize the need for coordinated One Health control strategies. Full article

Mpox is a zoonotic infectious disease caused by the species Orthopoxvirus monkeypox (MPV), which is becoming an increasing public health concern. While human-to-human transmission of the virus is well established, the role of domestic animals in MPV infection remains poorly understood. Investigating how the virus is transmitted among humans, dogs, and cats can improve our understanding of the disease’s pathogenesis and help develop strategies to limit its dissemination during future outbreaks. In this study samples were collected from four domestic animals (three dogs and one cat) in May 2023. These animals lived in a household where a human mpox case had been confirmed by PCR in March 2023, approximately 2 months before animal sampling. A plaque reduction neutralization test (PRNT) using vaccinia virus was performed to detect anti-orthopoxvirus (OPV) neutralizing antibodies (nAbs). Our data demonstrated that anti-OPV nAbs were present in samples obtained from three dogs and one cat with neutralization titers ranging from 1:5 to 1:20. These results indicate that the domestic animals were exposed to OPVs after contact with an individual with confirmed mpox, suggesting possible human-to-animal transmission within a household. Nevertheless, due to the cross-reactive immune response among OPVs, and the endemic circulation of vaccinia virus in Brazil, it is not possible to determine the specific viral species based solely on PRNT results. Therefore, these serological findings should be interpreted as evidence of OPV’s exposure rather than confirmed MPV infection. Full article

Background/Objectives: Healthcare workers (HCWs) were the most exposed job category to SARS-CoV-2, due to patient care, HCW-to-HCW transmission, and community exposure. However, the relative relevance of each source is still debated. To address this issue, this study investigated the dynamics of the professional and extra-professional determinants of infection across the pandemic among a large, multicenter cohort of HCWs. Methods: The study included 5576 HCWs from four Italian University Hospitals within a European Project, called ORCHESTRA. Socio-demographic and clinical data were collected retrospectively via online surveys from March 2020 to September 2022. Factors associated with SARS-CoV-2 infection during different pandemic periods were evaluated by a multinomial logistic regression model. Results were expressed as Relative Risk Ratios (RRR). Results: The cumulative incidence was 46.2%. The highest incidence period was the Omicron phase (OVP) (69.7%). The extra-professional source was the most reported (34.3%), followed by the occupational (26.8%). However, in almost 40%, the source was undetected. The RRR for occupational exposures was 0.39 (95% CI 0.25–0.61) during the Pre-Omicron variant Period (POP) and even lower (0.22, 95% CI 0.16–0.29) in the OVP, as compared to extra-professional exposures, using the Pre-Vaccination Period (PVP) as reference. Conclusions: The dominant source of infection among HCWs changed over time. While occupational contacts were more frequent during PVP, it significantly waned over the subsequent pandemic phases. Implementing procedures and guidelines to prevent infection, even outside the workplace during pandemics, would reduce the spread of infection among HCWs and patients. Full article

In May 2026, two outbreaks occurred at once: an Andes virus outbreak aboard the MV Hondius expedition cruise ship (13 cases (12 laboratory-confirmed and 1 probable), 3 deaths, and more than 600 contacts traced across 32 countries and territories; passengers and crew from 23 countries; data as of 22 June 2026) and a Bundibugyo virus disease (BDBV) outbreak in Central Africa (more than 1000 laboratory-confirmed cases and more than 250 confirmed deaths in the Democratic Republic of the Congo and Uganda; data as of 22 June 2026). The two pathogens diverge sharply in their transmission epidemiology. Aboard the MV Hondius, person-to-person transmission was sustained across three generations from a single index case, and one asymptomatic, PCR-positive contact later developed symptoms, indicating pre-symptomatic ANDV RNA detection, although the extent to which this corresponds to infectiousness and onward transmission remains uncertain. BDBV, on current evidence, has not been documented to sustain pre-symptomatic transmission as a major driver of its outbreaks, which allows for contact tracing of different timing and intensity. This Perspective draws together the epidemiological data from the MV Hondius outbreak, the endemic-region experience (Chile’s 2021–2025 secondary attack rate of 5.7%; Argentina’s 1996 El Bolsón and 2018 Epuyén outbreaks), the molecular pathogenesis, the diagnostic platforms, the therapeutic pipeline (favipiravir, tocilizumab, Icatibant) and the vaccine strategies (USAMRIID DNA vaccine, phase 1 completed). We set the contact-tracing and active-surveillance protocols applied to ANDV against the less stringent protocols that may suffice for BDBV. Full article

Domestic cats (Felis catus) are ubiquitous companion animals that provide substantial psychological and social benefits to children and adults alike, but they also serve as reservoirs and vectors for a wide range of zoonotic pathogens. Close physical contact between cats and children, frequent use of shared environments such as homes, playgrounds, and sandboxes, and still-developing hygiene behaviours increase opportunities for exposure to protozoa, helminths, bacteria, fungi, and ectoparasite-borne agents. This review synthesizes current evidence on key feline-associated zoonoses of pediatric concern—including Toxoplasma gondii, Toxocara cati, Ancylostoma spp., Dipylidium caninum, Bartonella henselae, Salmonella enterica, Campylobacter jejuni, Pasteurella multocida, Microsporum canis, flea-borne Rickettsia species, and rabies—with emphasis on transmission routes, clinical manifestations, and risk modifiers in children, pregnant women, and immunocompromised individuals. Within a One Health framework, we also summarize global publication trends on feline zoonoses, discuss how urban cat ecology and management (including free-ranging cats in child-frequented environments) may shape pediatric risk, and outline practical prevention strategies centred on hygiene, veterinary care, and targeted education for caregivers and children. Full article

Real-time, non-contact velocity measurement of hot-rolled bars is critical for metallurgical process control, but conventional laser Doppler velocimetry (LDV) systems often fail in these environments. The intense broadband thermal radiation from targets up to 1000 °C, coupled with severe surface depolarization, overwhelms weak scattered signals in high-speed (up to 40 m/s) rolling zones. To address this issue, we developed a fully integrated, thermal-radiation-resistant LDV sensing system. Hardware optimization was achieved by eliminating polarized-light transmission and adopting a parallel-beam design, which significantly enlarges the laser overlap area and increases detection depth. Furthermore, a 1550 nm laser (100 mW) was coaxially combined with a 10 nm narrow-band filter to isolate the thermal background and boost signal strength. A customized workflow utilizing continuous Fourier transform (CFT) spectral refinement and energy centroid estimation was implemented to precisely extract the true Doppler shift. Performance evaluations show the system achieves an excellent signal-to-noise ratio (SNR) of 29,532. Allan variance analysis confirms a stable detection sensitivity of 0.003 m/s (0.1 s integration time), a local short-to-medium-term optimal limit of 1.6 × 10⁻⁴ m/s, and a statistical accuracy of 0.005 m/s. Finally, the system was successfully deployed on an industrial rolling mill production line. It provided reliable velocity feedback for mill speed adjustment, achieving a near-zero-tension rolling process and fundamentally resolving workpiece dragging, squeezing, and steel pile-up. Full article