Search Results (46)

Yardlong bean is a vegetable type of cowpea grown for fresh and immature pods. “Thua Ngu” is a specialty yardlong bean cultivar with its unique snake-like pod surface and highly crispy pods that may be useful for the breeding of a new cultivar(s). The objectives of this study were to determine the mode of inheritance of the snake-like pod trait and locate the genome region controlling this trait in Thua Ngu. Microscopic observation revealed that the shape, size, and organization of cells of immature and mature pods of Thua Ngu were clearly different from those of “Raya” (normal yardlong bean). Fiber analysis showed that lignin content in immature and mature pods of Thua Ngu was 2.05- and 3.45-fold higher than that in Raya. Segregation analysis using F₂ and F_2:3 populations of the cross Thua Ngu × Raya demonstrated that a single gene controls the snake-like pod trait. QTL-seq analysis using the F₂ population revealed a major locus, qSlp4.1, for the snake-like pod trait. Fine-mapping using F₂ and F_2:3 populations delimited qSlp4.1 to a 152.88 Kbp region containing nine genes. Genes with functions involved in cell morphology and/or lignin formation, including Vigun04g163400, Vigun04g163600, and Vigun04g163700, were identified as candidate genes for the snake-like pod trait. Full article

The liquid-core anti-resonant fiber (LCARF) has emerged as a versatile platform for applications in nonlinear photonics, biological sensing, and other domains. In this study, a systematic and comprehensive analysis of LCARF was conducted via the finite element method to evaluate its performance across a wavelength range of 400–1200 nm. This included an assessment of the effects of structural parameters such as capillary wall thickness and the ratio of cladding tube diameter to core diameter on confinement loss and effective refractive index. The results reveal that the proposed core-only-filled approach significantly reduces the confinement loss compared to the conventional fully filled approach, thus facilitating signal transmission. Furthermore, the optimization of geometrical parameters greatly improves the single-mode characteristics of LCARFs. This work establishes a robust theoretical framework and provides valuable support for enhancing the LCARF applications in optofluidics, thereby contributing to the evolution of specialty fiber technologies. Full article

This paper employs five different general-purpose optimization methods to perform parameter optimization on single-layer hollow antiresonant fibers. It provides guidance on the establishment of hyperparameters for various optimization methods, with the aim of further defining and standardizing the necessary conditions and convergence criteria for applying optimization algorithms to specialty optical fibers. Through numerical experiments, the study ultimately obtains the converged optimal performance and the range of optimized parameter guidance for single-layer, double-layer, and triple-layer antiresonant fibers with different topological structures. Full article

Microgreens are nutrient-dense foods rich in mineral nutrients and health-benefiting phytochemicals. They are a popular specialty crop with a rapidly increasing industry in the United States (U.S.A.) and worldwide. However, there is a lack of research-based recommendations regarding the feasibility of using hydroponic fiber mats in the production of herbal microgreens and their effects on yield, quality, and nutritional composition. This study assessed shoot development, yield, visual quality, and mineral composition of five herbal microgreen species, including basil, chives, dill, leek, and parsley when grown with four types of hydroponic fiber mats (BioStrate, hemp, jute, and MicroMat) and affected by a single post-emergent fertigation in two experiments. The five microgreens varied in yield, quality, mineral nutrient composition, and their response to substrate type. Chives microgreens produced the highest fresh and dry shoot weights among species when grown with BioStrate, jute, and MicroMat in both experiments. The four substrate types resulted in similar fresh and dry shoot weights in leek and parsley microgreens in both experiments. However, BioStrate and MicroMat increased fresh and dry shoot weights in chives in December compared with hemp or jute mats. Jute resulted in higher fresh and dry shoot weights in basil in both experiments compared with MicroMat. The fiber mats altered mineral nutrient concentrations in tested microgreen species. Hemp mats increased potassium concentrations in basil and dill, while jute mats produced the highest Fe concentrations in the two species and the highest Mn concentration in basil in both experiments. A single post-emergent fertigation increased shoot height and increased concentrations of nitrogen, phosphorus, potassium, sulfur, iron, zinc, manganese, and boron in one or both experiments. Full article

Standard single-mode telecommunication optical fiber is still one of the most popular in distributed acoustic sensing. Understanding the acoustic, mechanical and optical features of various fibers available currently can lead to a better optimization of distributed acoustic sensors, cost reduction and adaptation for specific needs. In this paper, a study of the performances of seven fibers with different coatings and production methods in a distributed acoustic sensor setup is presented. The main results include the amplitude–frequency characteristic for each of the investigated fibers in the range of acoustic frequencies from 100 to 7000 Hz. A single-mode fiber fabricated using the modified chemical vapor deposition technique together with a polyimide coating has shown the best sensitivity to acoustic events in the investigated range of frequencies. All of this allows us to both compare the studied specialty fibers with the standard single-mode fiber and choose the most suitable fiber for a specific application, providing an enhancement for the performance of distributed acoustic sensors and better adaptation for the newly aroused potential applications. Full article

Para-aramid fibers, known for their remarkable strength and thermal stability, are frequently employed in protective textiles for military and aerospace applications. However, continuous exposure to ultraviolet (UV) radiation can damage their protective characteristics. This study analyzes the ultraviolet protection factor (UPF) and UV transmittance of woven fabrics produced from 30/2 Ne spun para-aramid yarns in the warp and 10 Ne core-spun yarns in the weft. The weft yarns consisted of three sheath fibers—para-aramid, meta-aramid, and polyester—in combination with different specialty core materials. The results show significant differences in UPF before and after UV exposure, with para-aramid sheaths giving the highest improvement. UV exposure caused structural changes in the fibers, resulting in increased UV protection, particularly in fabrics with para-aramid sheaths. This study concludes that the combination of para-aramid fibers with specific core materials significantly enhances UV protection, making them well-suited for applications in high UV exposure environments. Full article

In this work, we propose a fiber Bragg grating (FBG)-based sensor for curvature measurements. Two gratings are inscribed through the protective coating in a specialty optical fiber using focused femtosecond laser pulses and point-by-point direct writing technology. One grating is inscribed on the central core adjacent to an air channel, while the other is inscribed on the eccentric core. The bending characteristics of the two-core fiber strongly depend on the bending direction due to the asymmetry of the fiber cores. A bending sensitivity of 58 $\mathrm{p}\mathrm{m}/{\mathrm{m}}^{-1}$ is achieved by the FBG in the eccentric fiber core over the curvature range of 0–50 ${\mathrm{m}}^{-1}$. Temperature and humidity cross-sensitivity could be significantly reduced by analyzing the differences in peak shifts between the two gratings. The sensor features a large sensing range and good robustness due to the presence of its protective buffer coating, which makes it a good candidate for curvature sensing in engineering fields. Full article

This paper evaluates the modification of fiber morphology and the strength property development of paper from Enset fiber as a function of soda pulping conditions and refining energy. Soda pulping was conducted at pulping temperatures between 160 and 180 °C. The NaOH charge was 16, 20, and 24% based on the initial raw material. The beating of pulp was conducted using a Jokro mill. The refining of pulp was conducted in a laboratory refiner at different refining intensities. The mild Jokro mill beating was not effective on Enset fiber pulp. On the other hand, the laboratory refiner effectively refined the pulp. The fiber morphology was altered in the way of improving the paper formation and strength. The beating degree of the pulp was increased to about 49 °SR. The tensile index was enhanced to around 80 Nm/g using a refining energy input of 250 kwh/t. From the results, it can be concluded that Enset fiber pulp is suitable for packaging papers due to its high strength level. On the other hand, Enset fiber can be a potential raw material for specialty papers like filter paper and tea bags because of its high porosity. Full article

Lignin, the earth’s second-most abundant biopolymer after cellulose, has long been relegated to low-value byproducts in the pulp and paper industry. However, recent advancements in valorization are transforming lignin into a sustainable and versatile feedstock for producing high-value biofuels, bioplastics, and specialty chemicals. This review explores the conversion of lignin’s complex structure, composed of syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H) units, into value-added products. We critically assess various biochemical and analytical techniques employed for comprehensive lignin characterization. Additionally, we explore strategies for lignin upgrading and functionalization to enhance its suitability for advanced biomaterials. The review emphasizes key areas of lignin valorization, including catalytic depolymerization methods, along with the associated challenges and advancements. We discuss its potential as a feedstock for diverse products such as biofuels, bioplastics, carbon fibers, adhesives, and phenolic compounds. Furthermore, the review briefly explores lignin’s inherent properties as a UV protectant and antioxidant, alongside its potential for incorporation into polymer blends and composites. By presenting recent advancements and case studies from the literature, this review highlights the significant economic and environmental benefits of lignin valorization, including waste reduction, lower greenhouse gas emissions, and decreased reliance on non-renewable resources. Finally, we address future perspectives and challenges associated with achieving large-scale, techno-economically feasible, and environmentally sustainable lignin valorization. Full article

Optical fiber biosensors can be used to develop point-of-care tests (POCTs) for detecting viruses and bacteria in several matrices. In particular, the surface plasmon resonance (SPR) and localized SPR phenomena (LSPR) can be excited by exploiting low-cost and small-size optical fiber chips. Generally, SPR or LSPR sensors are realized using several kinds of modified optical fibers (silica, plastic, or specialty) or by exploiting other optical waveguides (e.g., slab, spoon-shaped waveguides, etc.). More specifically, optical fiber sensors can be classified as intrinsic or extrinsic. In the “optical fiber intrinsic sensors”, the sensing area is realized in the optical fiber directly, such as in the case of plasmonic platforms based on D-shaped plastic optical fibers (POFs), tapered optical fibers, U-bend POFs, or light-diffusing fibers (LDFs). By contrast, when an optical fiber is used as a mere waveguide allowing for the launch of light to the sensing region and its collection, it is defined as an extrinsic optical fiber sensor, like in the case of the plasmonic sensors realized by Cennamo et al. using POFs combined with spoon-shaped waveguides, 3D-printed platforms, bacterial cellulose waveguides, nanogratings, and InkJet-printed chips. To realize optical biosensor chips for the detection of viruses and bacteria, both intrinsic and extrinsic plasmonic POF sensors can be efficiently combined with receptors specific for membrane proteins, either biological (e.g., antibodies, aptamers, enzymes, etc.) or synthetic (e.g., molecularly imprinted polymers), to build groundbreaking POCTs. Full article

Fiber-optic biosensors based on localized surface plasmon resonance (LSPR) have the advantages of great biocompatibility, label-free, strong stability, and real-time monitoring of various analytes. LSPR fiber-optic biosensors have attracted extensive research attention in the fields of environmental science, clinical medicine, disease diagnosis, and food safety. The latest development of LSPR fiber-optic biosensors in recent years has focused on the detection of clinical disease markers and the detection of various toxic substances in the environment and the progress of new sensitization mechanisms in LSPR fiber-optic sensors. Therefore, this paper reviews the LSPR fiber-optic sensors from the aspects of working principle, structure, and application fields in biosensors. According to the structure, the sensor can be divided into three categories: traditional ordinary optical fiber, special shape optical fiber, and specialty optical fiber. The advantages and disadvantages of existing and future LSPR fiber-optic biosensors are discussed in detail. Additionally, the prospect of future development of fiber-optic biosensors based on LSPR is addressed. Full article

Multiple Sclerosis (MS) is characterized by chronic deterioration of the nervous system, mainly the brain and the spinal cord. An individual with MS develops the condition when the immune system begins attacking nerve fibers and the myelin sheathing that covers them, affecting the communication between the brain and the rest of the body and eventually causing permanent damage to the nerve. Patients with MS (pwMS) might experience different symptoms depending on which nerve was damaged and how much damage it has sustained. Currently, there is no cure for MS; however, there are clinical guidelines that help control the disease and its accompanying symptoms. Additionally, no specific laboratory biomarker can precisely identify the presence of MS, leaving specialists with a differential diagnosis that relies on ruling out other possible diseases with similar symptoms. Since the emergence of Machine Learning (ML) in the healthcare industry, it has become an effective tool for uncovering hidden patterns that aid in diagnosing several ailments. Several studies have been conducted to diagnose MS using ML and Deep Learning (DL) models trained using MRI images, achieving promising results. However, complex and expensive diagnostic tools are needed to collect and examine imaging data. Thus, the intention of this study is to implement a cost-effective, clinical data-driven model that is capable of diagnosing pwMS. The dataset was obtained from King Fahad Specialty Hospital (KFSH) in Dammam, Saudi Arabia. Several ML algorithms were compared, namely Support Vector Machine (SVM), Decision Tree (DT), Logistic Regression (LR), Random Forest (RF), Extreme Gradient Boosting (XGBoost), Adaptive Boosting (AdaBoost), and Extra Trees (ET). The results indicated that the ET model outpaced the rest with an accuracy of 94.74%, recall of 97.26%, and precision of 94.67%. Full article

In this paper, a ratiometric approach to sensing temperature variations is shown using specialty fiber optic devices. We analyzed the transmission response of cascaded segments of multicore fibers (MCFs), and dissimilar lengths were found to generate an adequate scheme for ratiometric operation. The perturbation of optical parameters in the MCFs translates to a rich spectral behavior in which some peaks increase their intensity while others decrease their intensity. Thus, by selecting opposite-behavior peaks, highly sensitive ratiometric measurements that provide robustness against spurious fluctuations can be performed. We implemented this approach using seven-core fiber (SCF) segments of 5.8 cm and 9.9 cm. To test the system’s response under controlled perturbations, we heated one of the segments from ambient temperature up to 150 °C. We observed defined peaks with opposite behavior as a function of temperature. Two pairs of peaks within the interrogation window were selected to perform ratiometric calculations. Ratiometric measurements exhibited sensitivities 6–14 times higher than single-wavelength measurements. A similar trend with enhanced sensitivity in both peak pairs was obtained. In contrast to conventional interferometric schemes, the proposed approach does not require expensive facilities or micrometric-resolution equipment. Moreover, our approach has the potential to be realized using commercial splicers, detectors, and filters. Full article

The properties of specialty optical fiber technology are determined by many aspects, such as the choice of material from which optical fibers are made, the refractive index profile, or the optical fiber manufacturing method. Typical optical fibers are made from ultrapure silicon dioxide (SiO₂), called fused silica, in a process called chemical vapor deposition (CVD). The differences between refractive indexes are most often obtained by doping silica glass with selected inorganic compounds, mainly germanium dioxide (GeO₂), which increases the refractive index, and fluorine, which lowers it accordingly. The proper design of the dopant profile in the optical fiber core and in the layer surrounding the core is crucial for nonlinear optical fibers with shaped dispersion characteristics. Such optical fibers can be used for the generation of nonlinear phenomena, such as supercontinuum generation (broadband light source) or soliton self-frequency shift. As part of the research, structures of nonlinear optical fibers with flattened normal dispersion in the near-infrared range were designed through the use of numerical simulations in COMSOL Multiphysics. The theoretical chromatic dispersion characteristics and dependence of the effective mode field area on the wavelength were obtained from the theoretical structures. Based on the designed optical fiber structures, a series of nonlinear optical fibers were produced, which were characterized by a high concentration of GeO₂ in the core and the presence of a fluorine-doped layer around the core. The influence of geometrical parameters, e.g., the width of the fluorine-doped layer (ratio of the radius of the fluorosilicate layer to the radius of the core), and the imperfections resulting from the technological aspects on the optical properties of manufactured optical fibers, with a particular emphasis on chromatic dispersion and the effective mode field area, was determined experimentally. Theoretical optical fiber models, along with their calculated properties (chromatic dispersion and effective mode field area), were compared with real measurements. Full article

A very simple to realize, low-cost, and highly sensitive plasmonic sensor, based on a polymeric light-diffusing fiber (LDF), is presented. The proposed surface plasmon resonance (SPR) sensor is realized by sputtering a gold nanofilm on an LDF made of PMMA. More specifically, a plastic LDF manufactured by GLOBAL ENGINEERING NETWORK SRL (Dosson di Casier, Italy) is used to realize this sensor. The optical fiber is an uncladded POF, with a simil-PMMA core of about 1600 μm in diameter and a removable jacket of about 400 μm (total diameter of about 2 mm). The SPR sensor is achieved by removing the jacket with a mechanical stripper and covering the exposed LDF surface with a 60 nm-thick gold film with a length of about 120 mm. The obtained sensor’s sensitivity varies linearly with the refractive index, and it ranges from about 1000 (nm/RIU) to almost 3000 (nm/RIU) in the considered refractive index range (from 1.332 RIU to 1.392 RIU). The obtained sensitivity values are comparable with those achieved using other SPR optical fiber sensors, but with the advantage of having a very simple production process, which does not require optical fiber modifications (such as the polishing process, tapering process, etc). So, the proposed LDF-based plasmonic sensor could be used to realize novel kinds of optical biosensors and chemical sensors. Full article