Simple Fiber Research Articles

Evaluation of the impact of hollow fiber pore size and membrane material on virus concentration using a handheld hollow fiber method.

Virus concentration using hollow fibers is widely used for vaccine production to maintain viral infectivity with low shear stress and to allow for easier scale-up of production. However, research laboratories often have limited available viral materials at the early stage of vaccine development, making it difficult to find an optimal hollow-fiber. In addition, few research articles have reported on optimizing hollow fiber pore size and membrane structure for virus concentration. In this study, the previously established handheld hollow fiber virus concentration method was modified to reduce the sample volume required and to enable simple and easy hollow fiber screening. The handheld hollow fiber screening method for virus concentration was confirmed to be effective using Zika as a model virus.

Sustainable surface coating strategy for the Interface compatibilization of hybrid high-density polyethylene microfibers and geopolymer-based composite: A versatile path for an efficient brittle to ductile-like transition

Geopolymer-based mortars (GMs) are known for their high compressive strength, but their brittleness under tensile and bending loads has limited their structural applications. To overcome these challenges, enhancing the fiber-matrix interface in fiber-reinforced GMs is crucial to achieve better load transfer. In this study, we employed an eco-friendly, non-invasive, and scalable surface coating method by dispersing metakaolin particles on the fiber surface. The fibers' chemical structure, morphology, thermal stability, and mechanical properties were analyzed, confirming the successful treatment with no major defects. When incorporated into GMs at 0.3 wt.%/binder, the treated fibers achieved remarkable mechanical improvements, including a 1,065% increase in flexural toughness, a 190% rise in flexural strength, and notable strain-hardening behavior, marking a transition from brittle to ductile-like failure. Additionally, the flexural modulus, split tensile strength, and compressive strength increased by 92%, 154%, and 7%, respectively. These results demonstrate the effectiveness and the potential of such a simple and sustainable fiber compatibilization strategy in developing durable, high-performance fiber-reinforced geopolymer composites for construction applications.

Spontaneous net flow generation using passive artificial cilia in the nucleate boiling region

The occurrence of spontaneous net flows in nature is fascinating. Here, we report spontaneous net flow generation using passive artificial cilia consisting of directional fabric in the nucleate boiling regime. Surprisingly, by placing simple ordinary flocking rayon fibers at an angle of approximately 18 degrees on a base cloth on the circular wall in a container as the artificial cilia, we observed the circular flow of the angular velocity of up to ∼2 rad/s (the average velocity of up to ∼34 mm/s) in the nucleate boiling regime. Moreover, by the observation of a high-speed camera (960 fps), we found that the bubbles rise obliquely at a high velocity of about 80–180 mm/s, which drives the net flow. Our findings should contribute to a better understanding of spontaneous flows in nature and should be applied to utilize unused heat, such as factory waste heat effectively.

Zero and double-knotted droplet-shaped optical fiber sensor for rapid temperature variation monitoring

Compact, simple optical fiber sensors based on a macro-bend fiber configuration were fabricated and proposed for instantaneous temperature measurement. These fiber sensors were manufactured by straightforwardly mechanically bending two different pieces of single-mode fiber (SMF) into zero-knotted droplet-shaped and double-knotted droplet-shaped, separately, with radii of a few millimeters. The sharp bending excites mode interferences among the core mode and the stimulated modes transmitting in the cladding region of the silica SMF. Many resonant interference fringes were perceived in the transmission signal and were noticed to shift to a shorter spectral region with the rise of environmental temperature (ET). The resultant data prove the practicality of the fabricated optical fiber sensors with excellent temperature sensitivities of about −1.128 nm/°C and −1.904 nm/°C, for zero-knotted droplet-shaped and double-knotted droplet-shaped, respectively, which is several times larger than sensors based on straight-transmitted fiber constructions. The proposed sensors’ structures may contribute effectively to temperature variations monitoring for environmental or industrial uses due to their large thermo-optical coefficient of the silica core and the big RI difference between the core and cladding of the bending fiber section.

Tailoring supercontinuum generation in a cascaded random Raman fiber laser based on a tunable noise pump.

The control of temporal noise of the pump could add an additional degree of freedom to manipulate the spectrum of continuous-wave (CW) pumped SC generation. In this paper, we experimentally tailor the CW-pumped supercontinuum (SC) generation in a cascaded Raman random fiber laser (CRRFL) based on a 1 µm pump with tunable temporal dynamics. The pump is based on a spectrally filtered ytterbium-doped random fiber laser (YRFL) seed laser, which can be amplified to a 10 W level with the tunable temporal noise. By increasing the detuning between the wavelength of a filter and the central wavelength of a YRFL, the temporal noise of the pump can be gradually increased, and we experimentally demonstrate the larger temporal noise of the pump can significantly enhance the spectral performance of SC generation in terms of spectral bandwidth and flatness. As a result, we realize the enhanced SC generation in a CRRFL with a more than doubled -10 dB bandwidth in a 50-km-long single-mode fiber by optimizing the temporal dynamics of the pump. We also demonstrate the enhanced output power of the spectral-optimized SC generation to 1.27 W with a shorter cavity length. We anticipate the combination of a tunable temporal noise ytterbium-doped pump and CRRFL could provide a new route to realize high-power, ultra-broadband, and smooth SC generation in a simple fiber cavity.

Design of simple circular photonic crystal fiber having ultra-large negative dispersion and high birefringence for dispersion compensation

Design of simple circular photonic crystal fiber having ultra-large negative dispersion and high birefringence for dispersion compensation

Octave-wide broadening of ultraviolet dispersive wave driven by soliton-splitting dynamics

Coherent dispersive wave emission, as an important phenomenon of soliton dynamics, manifests itself in multiple platforms of nonlinear optics from fibre waveguides to integrated photonics. Limited by its resonance nature, efficient generation of coherent dispersive wave with ultra-broad bandwidth has, however, proved difficult to realize. Here, we unveil a new regime of soliton dynamics in which the dispersive wave emission process strongly couples with the splitting dynamics of the driving pulse. High-order dispersion and self-steepening effects, accumulated over soliton self-compression, break the system symmetry, giving rise to high-efficiency generation of coherent dispersive wave in the ultraviolet region. Simultaneously, asymmetric soliton splitting results in the appearance of a temporally-delayed ultrashort pulse with high intensity, overlapping and copropagating with the dispersive wave pulse. Intense cross-phase modulations lead to octave-wide broadening of the dispersive wave spectrum, covering 200–400 nm wavelengths. The highly-coherent, octave-wide ultraviolet spectrum, generated from the simple capillary fibre set-up, is in great demand for time-resolved spectroscopy, ultrafast electron microscopy and frequency metrology applications, and the critical role of the secondary pulse in this process reveals some new opportunities for all-optical control of versatile soliton dynamics.

Generation of high-energy self-mode-locked pulses in a Tm-doped fiber laser

The incorporation of a material-based or artificial saturable absorber into a fiber laser cavity imposes a limitation on energy enhancement owing to its low damage threshold and high environmental sensitivity. To address this issue, one promising alternative approach is the utilization of the self-mode-locking technique. Here, we present a robust self-mode-locked Tm-doped fiber laser with high pulse energy emission. A simple and compact fiber laser structure is realized by utilizing a section of a Tm-doped fiber, serving both as a gain medium and a saturable absorber. Thus, the operational stability is enhanced, especially under high-energy conditions. Furthermore, the realization of high-energy pulses is accomplished through the integration of dispersion management technique. Experimental results reveal that the maximum single-pulse energy increases from 34.8 pJ to 120.2 nJ as the round-trip group delay dispersion decreases from −0.43 to −12.40 ps2. The proposed self-mode-locked Tm-doped fiber laser under high-energy operation exhibits remarkable performance. Our results provide a simple approach to obtaining a mid-infrared laser source with high pulse energy and hold significant potential for advancing high-energy laser systems.

A simple structure and high sensitivity side-polished micro-structured fiber RI sensor based on gold-coated open-loop channel

A simple structure and high sensitivity side-polished micro-structured fiber RI sensor based on gold-coated open-loop channel

Numerical analysis and detection of cancer cells using a dual-core gold coated plasmonic biosensor

In this research, a simple dual-core photonic crystal fiber (PCF) that leverages surface plasmon resonance (SPR) to operate as a bio-sensor in the visible to near-infrared range is proposed. An external analyte channel is constructed by putting a gold plasmonic metal layer over the fiber sensor. A numerical investigation employing the wavelength interrogation approach reveals that the maximal wavelength and amplitude sensitivity are 22000 nm/RIU and 1561.4 RIU-1, respectively. The high wavelength resolution for this suggested sensor is 4.54 × 10−6 RIU, and that suggests a high detection range. The proposed sensor is designed for the detection of any molecules from the RI range 1.33 to 1.42, and it can detect six different types of cancerous cells (the refractive index of different cancerous cells varied from 1.380 to 1.401) in this range. According to the obtained numerical results, MCF-7 cells exhibit the highest wavelength sensitivity of 6428.6 nm/RIU and amplitude sensitivity of 766.361 RIU-1. Furthermore, the sensor will be able to detect different viruses, proteins, DNA/RNA strands, and other things in this sensing range. This sensor offered the potential to detect biochemical solutions and biological samples due to its high sensitivity and simple shape.

Modified failproof physics-informed neural network framework for fast and accurate optical fiber transmission link modeling

Physics-informed neural networks (PINNs) have recently emerged as an important and ground-breaking technique in scientific machine learning for numerous applications including in optical fiber communications. However, the vanilla/baseline version of PINNs is prone to fail under certain conditions because of the nature of the physics-based regularization term in its loss function. The use of this unique regularization technique results in a highly complex non-convex loss landscape when visualized. This leads to failure modes in PINN-based modeling. The baseline PINN works very well as an optical fiber model with relatively simple fiber parameters and for uncomplicated transmission tasks. Yet, it struggles when the modeling task becomes relatively complex, reaching very high error, for example, numerous modeling tasks/scenarios in soliton communication and soliton pulse development in special fibers such as erbium-doped dispersion compensating fibers. We implement two methods to circumvent the limitations caused by the physics-based regularization term to solve this problem, namely, the so-called scaffolding technique for PINN modeling and the progressive block learning PINN modeling strategy to solve the nonlinear Schrödinger equation (NLSE), which models pulse propagation in an optical fiber. This helps PINN learn more accurately the dynamics of pulse evolution and increases accuracy by two to three orders of magnitude. We show in addition that this error is not due to the depth or architecture of the neural network but a fundamental issue inherent to PINN by design. The results achieved indicate a considerable reduction in PINN error for complex modeling problems, with accuracy increasing by up to two orders of magnitude.

Hydrophobic Silk Fibroin-Agarose Composite Aerogel Fibers with Elasticity for Thermal Insulation Applications.

Aerogel fibers, characterized by their ultra-low density and ultra-low thermal conductivity, are an ideal candidate for personal thermal management as they hold the potential to effectively reduce the energy consumption of room heating and significantly contribute to energy conservation. However, most aerogel fibers have weak mechanical properties or require complex manufacturing processes. In this study, simple continuous silk fibroin-agarose composite aerogel fibers (SCAFs) were prepared by mixing agarose with silk fibroin through wet spinning and rapid gelation, followed by solvent replacement and supercritical carbon dioxide treatment. Among them, the rapid gelation of the SCAFs was achieved using agarose physical methods with heat-reversible gel properties, simplifying the preparation process. Hydrophobic silk fibroin-agarose composite aerogel fibers (HSCAFs) were prepared using a simple chemical vapor deposition (CVD) method. After CVD, the HSCAFs' gel skeletons were uniformly coated with a silica layer containing methyl groups, endowing them with outstanding radial elasticity. Moreover, the HSCAFs exhibited low density (≤0.153 g/cm3), a large specific surface area (≥254.0 m2/g), high porosity (91.1-94.7%), and excellent hydrophobicity (a water contact angle of 136.8°). More importantly, they showed excellent thermal insulation performance in low-temperature (-60 °C) or high-temperature (140 °C) environments. The designed HSCAFs may provide a new approach for the preparation of high-performance aerogel fibers for personal thermal management.

When simplicity triumphs: niche specialization of gut bacteria exists even for simple fiber structures.

Structurally complex corn bran arabinoxylan (CAX) was used as a model glycan to investigate gut bacteria growth and competition on different AX-based fine structures. Nine hydrolyzate segments of the CAX polymer varying in chemical structure (sugars and linkages), CAX, five less complex non-corn arabinoxylans, and xylose and glucose were ranked from structurally complex to simple. The substrate panel promoted different overall growth and rates of growth of eight Bacteroides xylan-degrading strains. For example, Bacteroides cellulosilyticus DSM 14838 (Bacteroides cellulosilyticus) grew well on an array of complex and simple structures, while Bacteroides ovatus 3-1-23 grew well only on the simple structures. In a competition experiment, B. cellulosilyticus growth was favored over B. ovatus on the complex AX-based structure. On the other hand, on the simple structure, B. ovatus strongly outcompeted B. cellulosilyticus, which was eliminated from the competitive environment by Day 11. This adaptation to fine structure and resulting competition dynamics indicate that dietary fiber chemical structures, whether complex or simple, favor certain gut bacteria. Overall, this work supports a concept that fiber degraders diversify their competitive abilities to access substrates across the spectrum of heterogeneity of fine structural features of dietary fibers.

Dispersive wave generation in single higher-order modes of a large-core silica step-index fiber with pulse energies up to 12 nJ.

The generation of light in a laser system is constrained by the gain medium, limiting the available wavelengths. We demonstrate in-fiber generation of ultrafast pulses between ∼550 and 800 nm via dispersive wave generation (DWG), in higher-order modes (HOMs). Using higher-order modes enables power scaling, due to their large effective area compared to the fundamental modes of single-mode fibers and dispersion engineering, even in simple step-index fibers. The process occurs in a single higher-order mode, which we excite using passive glass components (an axicon and two telescopes). The output pulses have energies up to 12 nJ at the biologically relevant wavelength of 705 nm.

Comparing the impact of simple and educational point-of-decision messages on nutritional choice outcomes.

Emerging evidence suggests that point-of-decision messages may be an effective way to promote healthy food choices. Previous studies show improvements in overall nutritional quality, as well as increases in underconsumed food categories, such as fruits and vegetables, and underconsumed nutrients of public health concern, like dietary fiber. However, there have been multiple approaches used for delivering point-of-decision messages, including very brief messages that remind individuals to consider health during choice, as well as longer messages providing educational information about health benefits. While both approaches have demonstrated positive impacts on outcomes, there is no comparative evidence of the messages’ effectiveness. In this study, we examine the impact of four messages on two nutritional attributes of cereals selected in a two-round pre- and post-message breakfast cereal choice exercise with numerous (n = 33) breakfast cereals available. Data were collected via an online survey of adult US residents recruited from the Prolific consumer panel. Three of the messages were simple reminder messages (taste, health, fiber), while there was additionally a longer fiber-focused messaging detailing the health benefits of fiber. Findings show that the simple messages outperformed the longer educational message, though there were some trade-offs between general health and fiber messages. The simple dietary fiber-focused message resulted in significantly higher dietary fiber content in cereals chosen than in any other messaging condition, while the general health message did not result in significantly higher measures of nutritional quality than the simple fiber message. The results of the study suggest that simpler messages may be more effective at increasing the nutritional quality of food choices. Additionally, messages focused on specific nutrients lead to significantly greater increases in the content of those nutrients.

High FOM PCF-SPR refractive index sensor based on MgF2-Au double-layer films.

A simple twin-core D-shape photonic crystal fiber sensor based on surface plasmon resonance (SPR) is designed for the measurement of refractive indices (RI). The twin-core D-shape structure enhances the SPR effect, and the M g F 2-Au dual-layer film narrows the linewidth in the loss spectrum, consequently improving both the sensitivity and figure of merit (FOM). The properties of the sensor are analyzed by the finite element method. In the RI range of 1.32-1.42, the maximum wavelength sensitivity, FOM, and resolution are 62,000nm/RIU, 1281R I U -1, and 1.61×10-6, respectively.

Simple Magnetic Polymeric Ionic Liquid Nanocomposite Coated Hollow Fiber Membrane for the Determination of Lead (II) and Copper (II) in Water and Fruit Juice with Microinjection Sampling-Flame Atomic Absorption Spectrometry (MIS-FAAS)

A novel and effective adsorbent based on magnetic polymeric ionic liquid nanocomposite-coated hollow fiber membrane (MPILNC-HFM) was developed and applied for magnetic solid phase extraction of Pb (II) and Cu (II) from environmental water and fruit juice samples with microinjection sampling-flame atomic absorption spectrometry (MIS-FAAS). During extraction process, the adsorbent coated on the surface of the hollow fiber can be removed from the solution using tweezers without using a magnet. Additionally, the need to use a centrifuge during adsorption and desorption steps is also eliminated, thereby increasing the speed, simplicity, and efficiency of the extraction process. The nanocomposite characterized through Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive x-ray (EDX) analyses to ensure its applicability. The experimental parameters were optimized by applying one-variable-at the-time (OVAT) approach. Under optimal conditions, limits of detection were achieved 16.5 µg L−1 for Pb (II) and 20.4 µg L−1 for Cu (II), respectively, with relative standard deviations up to 7.9% and relative recoveries in the range of 91.8%–02.2%.

Finite approximation properties of C*-modules III

Abstract We introduce and study a notion of module nuclear dimension for a C * \mathrm{C}^{*} -algebra A which is a C * \mathrm{C}^{*} -module over another C * \mathrm{C}^{*} -algebra 𝔄 {\mathfrak{A}} with compatible actions. We show that the module nuclear dimension of A is zero if A is 𝔄 {\mathfrak{A}} -NF. The converse is shown to hold when 𝔄 {\mathfrak{A}} is a C ⁢ ( X ) {C(X)} -algebra with simple fibers, with X compact and totally disconnected. We also introduce a notion of module decomposition rank, and show that when 𝔄 {\mathfrak{A}} is unital and simple, if the module decomposition rank of A is finite then A is 𝔄 {\mathfrak{A}} -QD. We study the set 𝒯 𝔄 ⁢ ( A ) {\mathcal{T}_{\mathfrak{A}}(A)} of 𝔄 {\mathfrak{A}} -valued module traces on A and relate the Cuntz semigroup of A with lower semicontinuous affine functions on the set 𝒯 𝔄 ⁢ ( A ) {\mathcal{T}_{\mathfrak{A}}(A)} . Along the way, we also prove a module Choi–Effros lifting theorem. We give estimates of the module nuclear dimension for a class of examples.

Plasmonic Optical Fiber Based Continuous in-Vivo Glucose Monitoring for ICU/CCU Setup.

This paper reports a sensor architecture for continuous monitoring of biomarkers directly in the blood, especially for ICU/CCU patients requiring critical care and rapid biomarker measurement. The sensor is based on a simple optical fiber that can be inserted through a catheter into the bloodstream, wherein gold nanoparticles are attached at its far distal end as a plasmonic material for highly sensitive opto-chemical sensing of target biomolecules (glucose in our application) via the excitation of surface plasmon polaritons. For specificity, the nanoparticles are functionalized with a specific receptor enzyme that enables the localized surface plasmon resonance (LSPR)-based targeted bio-sensing. Further, a micro dialysis probe is introduced in the proposed architecture, which facilitates continuous monitoring for an extended period without fouling the sensor surface with cells and blood debris present in whole blood, leading to prolonged enhanced sensitivity and limit of detection, relative to existing state-of-the-art continuous monitoring devices that can conduct direct measurements in blood. To establish this proof-of-concept, we tested the sensor device to monitor glucose in-vivo involving an animal model, where continuous monitoring was done directly in the circulation of living rats. The sensor's sensitivity to glucose was found to be 0.0354 a.u./mg.dl-1 with a detection limit of 50.89 mg/dl.

Artificial neural network-assisted optical fiber sensor for accurately measuring salinity and temperature

The observation of seawater salinity and temperature is indispensable for sustainable development and utilization of marine resources. In this research, a simple and low-cost single-mode fiber (SMF) - no-core fiber (NCF) - SMF structure based on Mach-Zehnder interference (MZI) is proposed to measure two variables with the assistance of an artificial neural network (ANN). In contrast to traditional wavelength linear fitting, direct matching of the entire spectrum to the variables through machine learning analysis effectively improves the accuracy of the output predictions. Specifically, mean absolute errors of salinity and temperature reduce from 1.540‰ to 0.808‰ and from 1.061 ℃ to 0.154 ℃, respectively. The relaxation of the light source and the optical spectrum analyzer (OSA) requirements, the fluctuation of salinity or temperature, the disturbance of environmental parameters will all not weaken the demodulation performance of the new method. Furthermore, the accuracy of the predicted results on the new probes demonstrates the adaptability of the demodulation approach. Importantly, ANN can simultaneously demodulate two parameters from a single spectrum, avoiding the cross-sensitivity problem in traditional methods. The strategy is highly generalizable and promising to be extended to any other parameters measured by optical fiber sensors.