Fiber Array Research Articles

Photonic Label-Free Biosensors for Fast and Multiplex Detection of Swine Viral Diseases.

In this paper we present the development of photonic integrated circuit (PIC) biosensors for the label-free detection of six emerging and endemic swine viruses, namely: African Swine Fever Virus (ASFV), Classical Swine Fever Virus (CSFV), Porcine Reproductive and Respiratory Syndrome Virus (PPRSV), Porcine Parvovirus (PPV), Porcine Circovirus 2 (PCV2), and Swine Influenza Virus A (SIV). The optical biosensors are based on evanescent wave technology and, in particular, on Resonant Rings (RRs) fabricated in silicon nitride. The novel biosensors were packaged in an integrated sensing cartridge that included a microfluidic channel for buffer/sample delivery and an optical fiber array for the optical operation of the PICs. Antibodies were used as molecular recognition elements (MREs) and were selected based on western blotting and ELISA experiments to ensure the high sensitivity and specificity of the novel sensors. MREs were immobilized on RR surfaces to capture viral antigens. Antibody–antigen interactions were transduced via the RRs to a measurable resonant shift. Cell culture supernatants for all of the targeted viruses were used to validate the biosensors. Resonant shift responses were dose-dependent. The results were obtained within the framework of the SWINOSTICS project, contributing to cover the need of the novel diagnostic tools to tackle swine viral diseases.

Simplified micromechanics approach to analysis the performance of UD composites

A simplified micromechanical approach is used for the modelling and analysis of unidirectional (UD) compositeperformance. In this paper, the influence of volume fraction and constituent properties on the effective longitudinal,transverse, and shear properties of unidirectional composites are investigated. These effective properties are determinedusing the micromechanical approach, which is based on mathematical modelling using the rule of mixtures. Four differenttypes of unidirectional composites such as T300/BSL914C, IM7/8511-7, T300/PR319, and S2-Glass/epoxy were used foranalysis purposes. The method was validated with existing experimental results. The response is dependent on an array ofparameters, such as the orientation of fibers, the volume fractions of fibers, array of fibers and the material properties oftheir constituents. Further, this micromechanical method might be used with other reinforcing fibers for the prediction ofproperties of UD, hybrid and other composites architectures.

The shell microstructure of the pteropod Creseis acicula is composed of nested arrays of S-shaped aragonite fibers: A unique biological material

The shell microstructure of the pteropod Creseis acicula is composed of nested arrays of S-shaped aragonite fibers: A unique biological material

A Model-Free Approach for Online Optimization of Nonlinear Systems

This paper proposes a strategy to search optimal control parameters of a complex nonlinear system using a metaheuristic optimization algorithm in a computationally efficient manner. The proposed algorithm, called BAS-swarm (Beetle Antennae Search-swarm), is a gradient-free optimizer based on the BAS algorithm, inspired by mimicking the food foraging behavior of beetles. BAS-swarm takes advantage of the fact that the antennae of insects are not single sensory organs. The antennae contain an array of tiny fiber. Antennae fiber enables the insects to have a microscopic insight into the environment when moving toward the source of food smell. BAS-swarm uses this insight to improve the performance of BAS by approximating the gradient direction at each iteration with the help of a swarm of antenna fiber. Since the proposed algorithm approximates gradient by mimicking the behavior of beetle antenna fiber located at random locations, it does not require the numerical computation of the actual gradient, making it very efficient for optimization of nonlinear non-convex systems. We verified the accuracy and efficiency of the proposed algorithm by training single-layer neural networks with nonlinear activation function and compared its performance with Particle Swarm Optimizer (PSO), a well-studied extremum seeking algorithm, and the original BAS algorithm. The experiment shows that the proposed algorithm provides several-fold improvement and faster convergence as compared to other metaheuristic algorithms.

High Density Carbon Fiber Array Assembly Machine for Brain Electrophysiological Recordings

High Density Carbon Fiber Array Assembly Machine for Brain Electrophysiological Recordings

Multi-aperture High Resolution Imaging Technology Based on Plastic Imaging Fiber Array

Multi-aperture High Resolution Imaging Technology Based on Plastic Imaging Fiber Array

Neutrino physics with an opaque detector

In 1956 Reines & Cowan discovered the neutrino using a liquid scintillator detector. The neutrinos interacted with the scintillator, producing light that propagated across transparent volumes to surrounding photo-sensors. This approach has remained one of the most widespread and successful neutrino detection technologies used since. This article introduces a concept that breaks with the conventional paradigm of transparency by confining and collecting light near its creation point with an opaque scintillator and a dense array of optical fibres. This technique, called LiquidO, can provide high-resolution imaging to enable efficient identification of individual particles event-by-event. A natural affinity for adding dopants at high concentrations is provided by the use of an opaque medium. With these and other capabilities, the potential of our detector concept to unlock opportunities in neutrino physics is presented here, alongside the results of the first experimental validation.

Vegetable waste and by-products to feed a healthy gut microbiota: Current evidence, machine learning and computational tools to design novel microbiome-targeted foods

Food waste management is a key issue to global food security and friendly environmental governance. Worldwide, one-third of food produced for human consumption is lost or wasted along the food supply chain, primary production and food processing representing the most significant loses. Therefore, the need to achieve zero waste production schemes is becoming a priority to meet Sustainable Development Goals. Increasing evidence points towards vegetable food waste as a rich source of a wide array of carbohydrate structures and fibres providing the opportunity to identify and develop alternative approaches to valorize agro-food waste. This review describes the valorization of vegetable waste and by-products via production of (novel) substrates targeted to gut microbiota modulation, emphasizing the importance of raw materials and structural-functional properties of carbohydrates. Furthermore, we propose a novel framework for the rational selection of vegetable sources with potential prebiotic activity, based on machine learning and other computational tools applied to available literature and public database information. Integration of the body of knowledge within the field of vegetable food waste valorization, from different perspectives, allows a rational selection of carbohydrate-based substrates with promising prebiotic activities. By exploring the interactions among dietary fibre and gut microbial ecosystems using computational tools fed with structural, functional and genomic data, we can identify substrates with potential to selectively stimulate gut commensals, in agreement with experimental evidence. Our approach establishes a new framework that can be extended to a wide range of commensal microbes and carbohydrate structures.

The diffraction detector for the EMD of the CSNS

On 23rd August 2018, the China Spallation Neutron Source (CSNS) located in Dongguan operated 4 neutron instruments. In the future, twenty neutron spectrometers will be built to provide multidisciplinary platforms for scientific research by national institutions, universities, and industries. Engineering Material Diffractometer (EMD), which will be used for strain measurements in engineering materials and components, will be constructed at the Beamline 8 in 2022. A novel thermal neutron detector, which will comply with the requirements of EMD application, is being developed. This detector will consist of 6LiF/ZnS(Ag) scintillation screens, wavelength shifting fiber (WLSF) arrays, a silicon photomultiplier (SiPM) and Application Specific Integrated Circuit (ASIC) read-out electronics. Each scintillation screen will be inclined with respect to the incident neutron beam at a grazing angle θ = 17°. Such geometry will not only improve the spatial resolution of detectors but also the neutron detection efficiency. The prototype of detector module has been tested at the neutron Beamline 20 at the CSNS. The experimental results obtained for this prototype illustrate that the pixel size of detector module is 3 mm and the detection efficiency exceeds 40% at the neutron wavelength of 1 Å. Based on these results, we design and manufacture the final version of the detector for the EMD application, which is characterized by low power consumption, highly integrated and easy to install. 70 such detectors will be installed till the end of 2021.

Development of multi-angle fiber array for accurate measurement of flexion and rotation in human joints

Herein, we have proposed a method that uses a highly stretchable and conductive fiber-based multi-angle fiber array, which precisely measures human joint motion in various degrees of freedom (flexion and rotation) at the shoulders, knees, and wrists in real time. By embedding conductive carbon nanotubes (CNTs) within spandex fibers of high elasticity and shape recovery ratio, we monitored joint motion stably without degrading the fiber’s conductivity even during repeated stretching and contraction of different lengths. The strain occurring in a specific direction was monitored using mapping images generated due to the change in resistance that occurred when 12 CNT-embedded spandex fibers arranged in radial lines at intervals of 15° were stretched or contracted by an external force. The proposed high-precision joint-monitoring technology measures human motion accurately and is applicable for use in wearable healthcare devices that require precise measurements.

High-quality and large-area echelle grating ruled on 500-mm ruling engine for the fiber array solar optical telescope (FASOT).

A 300 mm×500 mm large-area echelle grating with groove density of 79 grooves/mm is fabricated for the spectrometer of the fiber array solar optical telescope (FASOT). This paper focusses on measurement methods of the grating performance. We present a method to evaluate the grating's stray light intensity, which is measured to a level of 10-4. The directly measured grating efficiency is approximately 90% of the designed value, and an indirect measurement method based on the grating groove profile is proposed. Based on the Rayleigh criterion and the grating diffraction wavefront, a physical optics method and a geometric grating method are proposed and are used to calculate the actual grating resolving power; the calculated results exceed 95% of the grating's theoretical resolving power. These results show that the CIOMP-6 ruling engine has sufficient precision to fabricate high-quality, large-area echelle gratings.

An ABAQUS® plug-in for generating virtual data required for inverse analysis of unidirectional composites using artificial neural networks

This paper presents a robust ABAQUS® plug-in called Virtual Data Generator (VDGen) for generating virtual data for identifying the uncertain material properties in unidirectional lamina through artificial neural networks (ANNs). The plug-in supports the 3D finite element models of unit cells with square and hexagonal fibre arrays, uses Latin-Hypercube sampling methods and robustly imposes periodic boundary conditions. Using the data generated from the plug-in, ANN is demonstrated to explicitly and accurately parameterise the relationship between fibre mechanical properties and fibre/matrix interphase parameters at microscale and the mechanical properties of a UD lamina at macroscale. The plug-in tool is applicable to general unidirectional lamina and enables easy establishment of high-fidelity micromechanical finite element models with identified material properties.

Open-source Toolkit: Benchtop Carbon Fiber Microelectrode Array for Nerve Recording.

Conventional peripheral nerve probes are primarily fabricated in a cleanroom, requiring the use of multiple expensive and highly specialized tools. This paper presents a cleanroom "light" fabrication process of carbon fiber neural electrode arrays that can be learned quickly by an inexperienced cleanroom user. This carbon fiber electrode array fabrication process requires just one cleanroom tool, a Parylene C deposition machine, that can be learned quickly or outsourced to a commercial processing facility at marginal cost. This fabrication process also includes hand-populating printed circuit boards, insulation, and tip optimization. The three different tip optimizations explored here (Nd:YAG laser, blowtorch, and UV laser) result in a range of tip geometries and 1 kHz impedances, with blowtorched fibers resulting in the lowest impedance. While previous experiments have proven laser and blowtorch electrode efficacy, this paper also shows that UV laser-cut fibers can record neural signals in vivo. Existing carbon fiber arrays either do not have individuated electrodes in favor of bundles or require cleanroom fabricated guides for population and insulation. The proposed arrays use only tools that can be used at a benchtop for fiber population. This carbon fiber electrode array fabrication process allows for quick customization of bulk array fabrication at a reduced price compared to commercially available probes.

Lysine-doped polydopamine coating enhances antithrombogenicity and endothelialization of an electrospun aligned fibrous vascular graft

Accelerating in situ endothelialization while inhibiting thrombosis is critical for the success of small-caliber tissue-engineered vascular grafts (TEVGs). In this study, a lysine (Lys) doped polydopamine (PDA) coating strategy was exploited to functionalize the TEVGs for vascular tissue regeneration. Using electrospun aligned poly(L-lactide-co-caprolactone) (PLCL) fiber arrays as the demonstrating biomaterial, introduction of Lys to the dopamine polymerization process was found to promote the formation of PDA-Lys composite coating layer atop the fiber surface via Schiff base and Michael addition reactions. Such a surface functionalization remarkably improved the coating layer uniformity, wettability, and protein adsorption capacity. In vitro assessment showed that the PDA-Lys coating layer was anti-thrombogenic and anti-inflammatory, and accelerated the formation of confluent endothelial monolayer by promoting cell-fiber and cell-cell interactions. Upon implantation in a rabbit carotid artery replacement model for 3 months, the constructed TEVGs (2 mm inner diameter), with oriented fiber architecture parallel to the longitudinal axis of grafts, were confirmed to significantly suppress thrombosis and accelerate regeneration of endothelium and tunica media layer, thereby exhibiting a positive vascular remodeling and integration capability in revascularization. This study demonstrated that the lysine-doped PDA coating provided a facile and effective platform for the improvement of antithrombogenicity and endothelialization of TEVGs.

Nanoengineered Antiviral Fibrous Arrays with Rose-Thorn-Inspired Architectures

Herpes simplex virus (HSV) plagues billions of humans with infections globally. We have developed and demonstrated rose-thorn-inspired antiviral fibrous arrays by electrospinning a composite of polycaprolactone (PCL) polymer with a dispersion of anisotropic zinc oxide tetrapod nanoparticles (ZOTeN). This rose-thorn-mimicking material enables physical and chemical protection. Under blue-light stimulation, ZOTeN photocatalyzes the production of hydrogen peroxide for an accessible disinfection and sterilizing mechanism to prolong materials usage. Using scanning electron microscopy and X-ray photoelectron spectroscopy, we confirm the rose-thorn-inspired morphology and the chemical composition, respectively. The fibrous material has dose-dependent antiviral properties against both HSV-1 and HSV-2. The engineered mats can potentially be used for manufacturing antiviral garments, face coverings, and bandages.

Photoconductivity of Micrometer Long Organic Single Crystal Fiber Array Prepared by Evaporation‐Induced Self‐Assembled Method

AbstractMillimeter‐long organic fiber arrays of intramolecular charge transfer merocyanine HB194 dye were prepared by evaporation‐induced self‐assembled method. X‐ray diffraction spectroscopy indicated individual fibers are millimeter‐sized HB194 single crystals. The elimination of defects and structural disorder enabled photoluminescence microscopy studies that revealed the intramolecular charge transfer (CT), bandgap excitonic state is long‐lived and remains largely localized in the absence of π‐orbital stacking in the crystalline structure. These nanosecond lifetimes explain the observation of a photoconductivity response upon irradiation with a 633 nm laser due to dissociation of the delocalized CT exciton to free carriers. At the same time, the photo response was increased 4.5 times by coating of the HB194 fiber array with polyvinyl alcohol. This increase is attributed to the larger dielectric field around the fibers that further facilitates the band‐gap (CT) exciton dissociation.

Design and analysis of hollow core Bragg fibers array for space division multiplexing

The space division multiplexing system is helpful to break through the transmission limitations of traditional optical communication systems. Inter-fiber separation and the number of alternating dielectric layers of Bragg fibers array (BFA) are considered with view to applying BFA to space division multiplexing system. The simulation results indicate that BFA with improper inter-fiber separation will result in topological edge state, thus leading to strong crosstalk and high confinement loss, and its crosstalk is hard to decrease with the increase of alternating dielectric layers. The confinement loss of each Bragg fiber in BFA with proper inter-fiber separation is greatly lower than that of traditional Bragg fiber with the same parameters. Our optimized BFA can be realized with low crosstalk of below −30 dB for 55.4 km propagation. In addition, the arrangement analysis of BFA in this paper provides some constructive suggestions for the application of traditional Bragg fiber in optical devices design such as BFA laser and omnidirectional emitting laser.

Solution-shearing of dielectric polymer with high thermal conductivity and electric insulation.

Polymer dielectrics, an insulating material ubiquitous in electrical power systems, must be ultralight, mechanically and dielectrically strong, and very thermally conductive. However, electric and thermal transport parameters are intercorrelated in a way that works against the occurrence of thermally conductive polymer electric insulators. Here, we describe how solution gel-shearing–strained polyethylene yields an electric insulating material with an outstanding in-plane thermal conductivity of 10.74 W m−1 K−1 and an average dielectric constant of 4.1. The dielectric constant and loss of such sheared polymer electric insulators are nearly independent of the frequency and a wide temperature range. The gel-shearing aligns ultrahigh–molecular weight polymer crystalline chains for the formation of separated and aligned nanoscale fibrous arrays. Together with lattice strains and the presence of boron nitride nanosheets, the dielectric polymer shows high current density carrying and high operating temperature, which is attributed to greatly enhanced heat conduction.

Coaxial 3D-Printed and kirigami-inspired deployable wearable electronics for complex body surfaces

Wearable electronics used to capture biological signals are substantially important in human–robot interactions, health monitoring, and clinical treatment. However, for curved or irregular body surfaces, intimate interfacing with the skin, which is essential for robust signal recording, is challenging. In this study, flexible core-sheath fiber sensors and adaptive devices were developed using a coaxial 3D printing technique and kirigami-inspired patterns. The printed core-sheath fiber, which was successfully applied in human–robot interaction, exhibited excellent electromechanical properties with a sensing strain range of 700%, and had high accuracy of approximately 3 mN and high electromechanical durability. In addition, the viscoelastic nature of the core material (shear-stiffening gel) provided the fiber array with fine energy dissipation performance against external harm by buffering the impact force by 51% while simultaneously capturing the dynamic impact in 4 ms. Moreover, the introduction of kirigami-inspired deformability to planar electronics facilitated conformable attachment of sensing devices with substantial adjustability to 3D curved surfaces; they can be adapted to shoe pads of different sizes without compromising their sensitivity. The 3D printing technique and kirigami-inspired pattern designs for creating adaptive and flexible wearable electronics hold great potential for advanced health monitoring of diverse and complex epidermal surfaces.

Predicting the optimal field enhancement factor during the growth of arched fibers

Curved carbon-based fibers, in the form of looped fibers, have been investigated as promising field electron emitters with high mechanical stability. Recently, the growth of semicircular arched carbon nanofibers (structures when the arch is incomplete) has received increased attention due to their potential application in next-generation electronic devices. In this Letter, we theoretically investigate the field enhancement factor (FEF) during the growth of these structures. We found the conditions for the optimal FEF, γmax, as a function of the geometrical parameters. Our results show that the local characteristic FEF at the top of the arch obeys a scaling law, γC≈γmax×Ω[(ψ/ψ*)2], where Ω is a nearly quadratic function of (ψ/ψ*), where ψ is a normalized arch angle of the fiber and ψ* is the ψ-value when γC=γmax. Importantly, our results show a universal behavior for γmax, namely, γmax≈κ[(R/r)α−0.45]ρ (where r and R are the radii of the fiber and the arch, respectively), α≡Rrim/r (where Rrim is the radius of the rim at the fiber top), and κ and ρ are positive constants. We point out several advantages of the arched fiber over the fully looped fiber for field emission devices, particularly the mechanical stability of the two-stage arched structures. Finally, starting with the conditions for γmax inferred from an isolated arch, the effects of electrostatic depolarization in regular arrays of arched fibers are analyzed as a function of the lattice parameters.