Search Results (975)

Due to the ultra-trace concentrations of perfluoroalkyl compounds (PFCs) existing in environmental aqueous matrices, it is imperative to develop sensitive and high-enrichment-efficiency approaches for the determination of these emerging pollutants. In this study, a nitrogen-doped carbon dot-functionalized hollow fiber membrane (NCDs@HFM) was fabricated and employed in solid-phase microextraction (SPME) mode for the simultaneous identification of eight perfluoroalkyl carboxylates (PFCAs). The NCDs@HFM offers several advantages, including multiple active binding sites, chemical durability, a large specific surface area and environmental compatibility. Owing to these properties, the NCDs@HFM-based SPME demonstrated high extraction efficiency for PFCAs, where enrichment factors for target molecules could reach 35–61 fold under the optimum conditions. This established method was then integrated with liquid chromatography–tandem mass spectrometry (LC-MS/MS) for the qualitative and quantitative analysis of eight representative PFCAs in drinking and environmental water samples. The limits of detection (LODs, S/N = 3) and quantitation (LOQs, S/N = 10) of the method were at the scale of 0.0018–0.015 μg/L and 0.006–0.050 μg/L, respectively. This proposed method exhibited good precision, with RSDs below 13.2% and satisfactory accuracy, with recoveries ranging from 70.6% to 122.5%. The developed method was successfully applied in the identification of eight typical PFCAs in drinking and environmental water samples. This method exhibits several merits, including low cost, high sensitivity, good reliability and reusability, representing a promising alternative for measuring trace levels of PFCAs in aqueous matrices. Full article

Fiber interferometers are widely used in precision measurement fields such as seismic observation, gravitational-wave detection, and aerospace guidance. However, phase noise in the Hz–kHz range has become an important factor limiting further improvement in measurement accuracy. In this work, a solid-core photonic crystal fiber (PCF) and a hollow-core photonic bandgap fiber (HC-PBGF) were introduced into the sensing arms of a fiber interferometer to reduce phase noise in this frequency range. Theoretical analysis showed that, compared with a conventional solid-core fiber, the PCF and the 19-cell HC-PBGF used in this study could reduce the phase noise by approximately 3 dB and 7 dB, respectively. The experimental results agreed well with the theoretical predictions, confirming that both fibers can effectively suppress high-frequency phase noise, with HC-PBGF showing superior noise reduction performance. This work provides a feasible approach for improving the performance of fiber interferometers in precision measurement. Full article

Background/Objectives: Ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CZA) are critical therapeutic options for multidrug-resistant Gram-negative infections; however, their comparative pharmacodynamics against carbapenem-resistant Pseudomonas aeruginosa (CRPA) remain incompletely defined. This study aimed to compare the bactericidal activity of C/T and CZA administered by intermittent infusion (II) or continuous infusion (CI) using a hollow fiber infection model (HFIM) against a clinical isolate of CRPA. Methods: Clinically relevant concentration–time profiles for C/T and CZA based on prescribing information were simulated in the HFIM. The standard P. aeruginosa strain ATCC 27853 and a GES-producing clinical CRPA isolate were utilized. The primary endpoint was bactericidal activity (≥3 log₁₀ CFU/mL reduction from baseline), while secondary endpoints included regrowth prevention and resistance development based on population analysis profiles (PAPs). Results: Against the standard strain, both agents achieved rapid killing without regrowth. However, for the GES-producing clinical isolate, C/T failed to achieve bactericidal activity. In contrast, CZA demonstrated sustained bacterial killing activity with the most pronounced early-phase bactericidal activity with CI of CZA (−4.25 log₁₀ CFU/mL at 24 h). The bactericidal activity was persistent over 7 days without bacterial regrowth after treatment discontinuation. Conversely, bacterial regrowth occurred with II of CZA after drug withdrawal. PAPs showed the lack of resistance development against CZA, whereas resistance to C/T developed within 48 h after initiating therapy. Conclusions: In this HFIM study, CI of CZA demonstrated the most sustained suppression of bacterial growth and prevented resistance emergence against the tested clinical isolate of CRPA producing GES β-lactamases. Future clinical studies are warranted to assess the effectiveness of the CI regimen. Full article

Coherent Raman scattering (CRS) techniques such as coherent anti-Stokes Raman scattering (CARS) provide chemically specific vibrational contrast with signal levels far exceeding spontaneous Raman scattering (SpRS). Extending these to broadband excitation enables multiplex detection across wide spectral regions, including the fingerprint region, CH-stretch bands and high-frequency vibrational modes. This review provides a structured overview of excitation architecture for broadband CRS, ranging from low-energy oscillator schemes to energy-scalable platforms. The discussion is organized along key design parameters, including spectral bandwidth, excitation intensity, and probe delay, which jointly determine the accessible operating regimes. Rather than representing competing methods, the reviewed architectures are presented as a complementary toolbox for application-driven spectroscopy in chemically reactive environments and complex biological systems. In addition, a representative OPCPA-based implementation is presented as a platform demonstration to illustrate accessible operating regimes, single-shot stability, and multiplex detection capability under realistic experimental conditions. Full article

Hollow fibers (HFs) have recently gained attention as an advantageous photocatalyst immobilizer for heterogeneous catalysis. Depending on their fabrication method, they can come up, or not, with a porous network within their structure. In this case, they are sometimes referred to as membranes, although they are not applied in liquid flow applications as filters. This work provides a concise overview of all the studies encountered in the literature on photocatalytic hollow fibers (HFs) and hollow fiber membranes (HFMs), clarifying the prevailing confusion about the topic. All publications are categorized with respect to their reported applications in batch liquid, flow, or gas experiments. Full article

During hemorrhagic procedures, autotransfusion is one of the main strategies for patient blood management. While conventional cell savers only concentrate red blood cells due to the centrifugation method, the innovative same™ autotransfusion medical device (i-SEP, Nantes, France), based on a hollow-fiber filtration technology, has the ability to preserve red blood cells along with the majority of platelets. Background/Objectives: The present study aimed at comparing the functionality of preserved platelets in the clot formation by using Quantra^® and/or ROTEM^® Point-Of-Care coagulation tests, after blood treatment for autotransfusion with either a standard centrifugation-based system (Xtra^® device, LivaNova, London, UK), or the filtration-based same™ device. Methods: First, coagulation was assessed in an in vitro experiment, where human blood samples were used to obtain ten treated blood products by each autotransfusion device that were evaluated with or without supplementation of plasma poor or rich in platelets. Then, to confirm the potential clinical benefit of the platelet preservation in a surgical context, coagulation was studied in vivo using a massive surgical hemorrhagic model on eight minipigs per device. Samples were collected after reinfusion steps and during a 6 h post-operative follow-up. Results: Both in vitro and in vivo, the same™ device consistently retained more platelets compared to the Xtra^® device. This enhanced preservation resulted in significantly stronger clot formation, likely due to higher platelet concentration and superior functional integrity. Conclusions: These findings highlight the potential clinical benefit of same™-recovered platelets for improving hemostasis during hemorrhagic surgery. Full article

The hollow fiber membrane humidification modules are used for indoor humidification in hot–dry regions and heating in winter. The module is composed of several flexible hollow fiber membranes, which are bent and displaced by gravity and fluid forces. This paper is a further study of previous work that reveals the internal relationship between the forces generated by vortex shedding and fiber vibration. The central trajectories of fibers in the flow field are described for various pulsating flow and fiber structure parameters. The effects of fiber displacement on fluid flow, heat transfer, and mass transfer performance at different parameters are discussed. The results show that the fiber displacement in the flow field consists of two components: (i) deformation caused by fluid drag force and gravity and (ii) periodic vibration caused by periodic lift and drag force as vortices shed at the fiber surface. The fiber vibration facilitates the vortex shedding on the fiber surface, which enhances the convective heat and mass transfer performance on the fiber surface. The average friction factor (f_m,v), Nusselt number (Nu_m,v), and Sherwood number (Sh_m,v) increased by 12.9%, 39.3%, and 20.0%, respectively, when the fiber vibrated compared to non-vibration. This implies that inducing fiber vibration can optimize the heat and moisture transfer performance. Full article

This study investigates the radiation-induced attenuation (RIA) of an Anti-Resonant Hollow-Core Fiber (AR-HCF) exposed to neutron and gamma radiation in a nuclear reactor environment. The AR-HCF—with a revolver-style structure—was characterized for RIA and compared to a solid, pure-silica-core fiber. Experimental results demonstrate that the AR-HCF exhibits substantially higher radiation tolerance compared to pure-silica, solid-core fibers, by about a factor of six in terms of dB/m. Numerical modeling in COMSOL Multiphysics (Version 6.3) was performed to simulate potential contributors of RIA, including silica compaction due to neutron fluence and changes in light confinement. These simulations ruled out these effects as primary causes of the measured attenuation. We also show that our results are consistent with the radiolytic generation of nitric acid within the hollow core, an interpretation that aligns with findings from a prior study. The results included in this manuscript provide insight into the behavior of AR-HCFs in the radiation field of a nuclear reactor, a topic with very limited prior literature, and underscore their potential for use in high-radiation environments such as fission and fusion reactors, particle accelerators, and space applications. The findings also point to promising future directions, including spectral characterization and dosimetry applications that leverage the unique properties of these fibers. Full article

This paper presents the design and experimental validation of a highly sensitive vector magnetic field sensor based on three mutually orthogonal Fabry–Perot interferometers (FPIs). The orthogonally arranged FPIs are bonded to a giant magneto-strictive material (GMM) block. Under an applied magnetic field, the magneto-strictively induced strain in the GMM block is transferred to the FPIs. Meanwhile, the FPIs, composed of single-mode fiber (SMF)–hollow-core fiber (HCF)–SMF, are further modulated by CO₂ laser, by which the higher sensitivities are obtained. The highest sensitivities of FPIs achieved 245.13, 159.06, and 168.59 pm/mT on the X-Y, X-Z, and Y-Z planes, respectively. By demodulating the distinct wavelength drifts of the three orthogonal FPIs, both the magnitude and direction of the magnetic field can be simultaneously determined. Full article

Background: Online hemodiafiltration (HDF) represents the most advanced form of kidney replacement therapy, combining diffusive and convective transport to enhance the removal of uremic toxins across a wide molecular spectrum. Achieving high convective volumes is a key determinant of treatment efficacy and has been associated with improved survival. Beyond small solutes, HDF targets middle molecules and protein-bound uremic toxins (PBUTs), including β₂-microglobulin, inflammatory cytokines, and other large uremic compounds implicated in cardiovascular and systemic complications. Aims: This narrative review examines advances in dialysis membrane materials, dialyzer design, and monitoring technologies that optimize mass transfer in HDF. It focuses on the interplay between membrane permeability, hemocompatibility, and convective dose delivery, and discusses how these engineering developments translate into clinical performance. Key mechanisms: Recent progress in synthetic polymer membranes, particularly polysulfone- and polyethersulfone-based systems, and hollow-fiber manufacturing has enabled improved control of pore size distribution, hydraulic permeability, and sieving characteristics. These developments enhance the clearance of middle molecules and selected PBUTs while preserving essential proteins such as albumin. Mechanistic insights into internal filtration, protein polarization, and Donnan effects highlight the complex transport processes occurring within the dialyzer and their interaction with automated HDF systems. Expanded hemodialysis and high-volume HDF approaches further increase the removal of larger solutes but require careful management to limit albumin loss and maintain hemocompatibility. Clinical implications: Optimized membrane design, combined with advanced HDF machine algorithms, allows delivery of high convective volumes under safe and stable conditions, improving removal of β₂-microglobulin, cytokines, and other clinically relevant toxins associated with inflammation and cardiovascular risk. However, treatment must remain individualized, considering electrolyte balance, albumin preservation, and patient-specific factors such as inflammation and nutritional status. Mechanistic modeling supports understanding of transport phenomena but must be interpreted cautiously when translated into clinical practice. Conclusions: Advances in membrane science, dialyzer engineering, and monitoring technologies have strengthened the role of HDF as a precision-based renal replacement therapy. Continued innovation aimed at optimizing middle-molecule and PBUT clearance while preserving albumin and treatment stability is essential to improve patient outcomes and support the broader implementation of HDF as a mainstream dialysis modality. Full article

The construction sector faces increasing pressure to reduce the embodied energy of building materials while valorizing industrial waste streams. This study evaluates the direct incorporation of post-industrial textile waste (100% cotton and cotton–polyester blends) in its native form to develop high-performance cementitious ceiling sheets. Composites were fabricated under a controlled hydraulic compaction pressure of 2.0 MPa, optimized to achieve matrix densification while preserving the integrity of the fibrous network. Viscoelastic recovery of the compressed fibers induced a hierarchical double-porosity architecture characterized by macro-voids and hollow fiber lumens. This microstructural evolution reduced thermal conductivity to 0.091 W/m·K, approximately 50% lower than commercial cement–fiber benchmarks—without compromising mechanical compliance. Scanning Electron Microscopy (SEM) revealed a mechanistic decoupling between water absorption and dimensional stability. Although the CP15 formulation (15 wt.% cotton–polyester) exhibited high moisture uptake (~21%), thickness swelling remained limited to 1.35%. This dimensional stability is attributed to the hydrophobic polyester framework, which bridges microcracks and constrains hygroscopic expansion within the cellulosic phase. The optimized CP15 composite achieved a Modulus of Rupture (MOR) of 8.75 MPa, exceeding ISO 8336 Category C, Class 2 requirements. Despite increased thickness, the areal density (10.84 kg/m²) remains compatible with standard gypsum-grade suspension systems, eliminating the need for structural modification. These findings establish a scalable, direct-valorization strategy for circular construction materials delivering enhanced thermal insulation and robust performance under tropical climatic conditions. Full article

Mid-infrared (MIR) femtosecond lasers, resonant with the absorption bands of amide-related molecular groups in the range of 6.1 to 6.5 μm, have been demonstrated to be effective for tissue ablation. However, the flexible and stable delivery of such pulses to micrometer-scale tissue regions for controlled ablation remains challenging. Here, we utilize a silica-based anti-resonant hollow-core fiber (AR-HCF) to deliver high-power MIR femtosecond pulses with high temporal and spectral fidelity, featuring pulse durations of approximately 340 fs and peak power densities exceeding 1 GW/cm², for selective tissue ablation. Benefiting from the small numerical aperture of the AR-HCF, a relatively stable and consistent beam spot size can be maintained over a millimeter-scale propagation distance. Precise control of the ablation depth can be achieved by appropriately selecting the scanning parameters, with penetration depths reaching the sub-millimeter scale. Furthermore, for the first time, we systematically compare the tissue ablation performance of MIR femtosecond lasers at resonant wavelengths (6.4 and 6.1 μm) and a non-resonant wavelength (5.5 μm) under identical scanning conditions. An ablation depth ratio of more than 8:1 is observed, demonstrating the high efficiency and selectivity of the resonance-based ablation mechanism. These results establish flexible delivery of high-power MIR femtosecond pulses in tissue-resonant bands via silica-based AR-HCF as a powerful platform for selective, precise, and efficient tissue ablation, providing a promising approach for interventional and minimally invasive surgery. Full article

Recycled concrete aggregates (RCAs) typically exhibit higher chloride permeability and lower strength compared to natural aggregates, potentially accelerating steel corrosion and compromising the durability of reinforced concrete structures. While functional additives like fibers, fly ash (FA), and glazed hollow beads (GHBs) are known to improve concrete properties, the quantification of the synergistic effects of their hybridization in RAC and a systematic multicriteria-based performance assessment are still lacking. This study experimentally investigates the individual and combined effects of GHB, FA, BF, and PPF on the compressive strength and electric flux of RAC. Fourteen mixtures were designed with different RCA replacements (0, 30, 50, and 100%), FA contents (0, 10, 20, and 30%), GHB dosages (0, 15, and 30%), and PPF and BF hybridization (0, 0.1 and 0.2%). Compared to unmodified RAC with 50% RCA replacement, the addition of 30% GHB significantly decreased the electric flux by 34.1% but comprised the compressive strength by 9.4%, whereas FA provided a weaker electric flux reduction of 16.3% alongside a lower strength decrease of 6.0%. A multicriteria analysis revealed that the synergistic GHB-FA-BF-PPF hybridization achieved the best performance of all formulations, exhibiting a remarkable 40.7% reduction in electric flux and a slight 1.3% increase in compressive strength compared to the unmodified RAC specimen. These findings demonstrate that the practical use of RAC modified by GHB-FA-BF-PPF hybridization would be highly beneficial in terms of mechanical performance as well as chloride permeability. Full article

The attosecond (10⁻¹⁸ s) light pulse represents the fastest time scale currently mastered by the scientific community, which enables the observation of electron dynamics within atoms and molecules, offering powerful tools to probe chemical reaction mechanisms and advance research in photovoltaic materials and biological processes. In this work, we investigate the generation of visible attosecond optical pulses via spectral broadening in Hollow-Core Fiber (HCF), followed by coherent recombination using a Three-Channel Light Field Synthesizer (TCLFS). The influence of the input pulse duration on Group Delay Dispersion (GDD), Third-Order Dispersion (TOD), and spectral broadening is systematically analyzed. Furthermore, the effects of GDD, TOD, and the carrier–envelope phase (CEP) on waveform synthesis are quantitatively examined for the first time. These findings provide valuable insights into dispersion management strategies essential for developing high-quality visible attosecond light sources, paving the way for future applications in ultrafast spectroscopy and light field-driven electron dynamics. Full article

The present review summarizes a vast body of literature on the subject of Membrane Distillation (MD), with a special emphasis on the existing results and correlations for the transmembrane transport of heat and mass. The issue of saltwater physical properties is also discussed in depth, whereas the advective transport of heat and salt concentration in the feed and permeate compartments is only briefly mentioned but is beyond the scope of this review. The paper does not aim to provide a complete treatment of the subject of MD, which can be found in other publications. Rather, it suggests the data and correlations most suitable for the range of operating conditions typically expected in actual units implementing Direct Contact Membrane Distillation (DCMD), including hollow fiber designs, with a view to assist model development. The focus is on MD for water desalination, although some results may apply well to other fields. Full article