A double helix-shaped optical fiber sensor for non-endoscopic diagnosis of gastrin-17.

Non-endoscopic tools for the diagnostic evaluation of patients should be promoted in the field of biomedical assay and the need for highly sensitive, efficient, low-cost, and user-friendly sensors must be considered. Optical fibers are widely used in sensors because their properties meet the physical requirements for biomedical detection. The spectrum responses of the sensor create changes in refractive index, wavelength shifts, and transmission loss. This study presents a double helix DNA-shaped optical fiber sensor for biosensors. The sensing principle of the DNA-shaped sensor is based on the whispering gallery mode (WGM) formed by the interference in the fiber's bending region. The refractive index interference changes corresponding to the core and cladding layers, which create shifts in the spectrum affected by the radius of the bend. A self-assembled sensor layer formed with nanoparticles was coated onto the DNA-shaped sensor in a sandwich structure. The wavelength shifts in spectral response are traced by the concentrations of gastrin-17 at 0.1, 1, 10, and 50 µg ml-1. The sensing layer was formed from a layer-by-layer assembly of gold nanoparticles to improve the performance of the surface plasmon resonance (SPR).

Real-Time and Sensitive Immunosensor for Label-Free Detection of Specific Antigen with a Comb of Microchannel Long-Period Fiber Grating.

This study aimed to develop a comb of microchannel and immunosensor based on long-period fiber grating using the process of Lithographie Galvanoformung Abformung-like micro-electromechanical systems (LIGA-like MEMS) for real-time and label-free detection of specific antigen. The coupling between propagating core and cladding modes was conducted from the comb of microchannel long-period fiber grating (CM-LPFG). The CM-LPFG-based immunosensor consisted of a microchannel structure through photoresist stacking processes and was sandwiched with an optical fiber to obtain a long-period structure. Specific immunoglobulin against protein antigen was immobilized onto an optical fiber surface and produced a real-time resonance effect on sensing specific protein antigen from the extracted protein mixtures of the cancer cell lines. The variable transmission loss was -14.07 dB, and the resonant wavelength shift was 11.239 nm. The low limit of detection for total protein concentration was 1.363 ng/µL. Our results revealed that the CM-LPFG-based immnosensor for real-time detection of label-free protein antigen is feasible and sensitive based on the diversification of a transmission loss and achieves specific immunosensing purposes for lab-on-fiber technology.

A Lamping U-Shaped Fiber Biosensor Detector for MicroRNA.

This study presents a U-shaped optical fiber developed for a facile application of microRNA detection. It is fabricated by the lamping process and packaged in a quartz tube to eliminate human negligence. In addition, silanization and electrostatic self-assembly are employed to bind gold nanoparticles and miRNA-133a probe onto the silicon dioxide of the fiber surface. For Mahlavu of hepatocellular carcinoma (HCC), detection is determined by the wavelength shift and transmission loss of a U-shaped optical fiber biosensor. The spectral sensitivity of wavelength and their coefficient of determination are found at -218.319 nm/ ng/mL and 0.839, respectively. Concurrently, the sensitivity of transmission loss and their coefficient of determination are found at 162.394 dB/ ng/mL and 0.984, respectively. A method for estimating the limit of detection of Mahlavu is at 0.0133 ng/mL. The results show that the proposed U-shaped biosensor is highly specific to miRNA-133a and possesses good sensitivity to variations in specimen concentration. As such, it could be of substantial value in microRNA detection.

Photoresist-free, laser-assisted chemical etching process for long-period fiber grating.

In this study, we propose a photoresist-free, laser-assisted wet chemical etching process used to control the grating depth of a long-period fiber grating (LPFG) termed laser-assisted etching LPFG (LLPFG). This process can considerably reduce production time, while the photoresist-free laser etching allows tiny long-period notches to be etched on the fiber surface, distinguishing the etching rate of the process from that of standard wet etching processes. The LLPFG, which has a period of 610 µm, was scanned using a KrF excimer laser. The results showed a resonant-attenuation wavelength of 1551 nm through a fiber diameter of 60 µm and a grating depth of 26 µm and to being a green process due to the photoresist-free etching.

A pathway for detection of gastric cancer biomarkers via using a layer-by-layer coated D-shaped grinding long-period fiber grating sensor.

Gastric cancer significantly contributes to global cancer mortality, often leading to inoperable stages and high recurrence rates post-surgery. Elevated levels of G-17 and G-gly have been identified as potential risk factors, particularly in patients with duodenal ulcers. This study introduces an innovative D-shaped grinding long-period fiber grating sensor (D-LLPFGs) designed for non-invasive detection of the gastrin G-17 antigen, employing a layer-by-layer chemical self-assembly to bond G-17 antibodies onto the fiber surface through hydrogen bonding. The D-LLPFGs sensor demonstrated significant spectral shifts within 1 min of antigen-antibody interaction, highlighting its rapid detection capability. At an optimized antibody concentration of 4 µg/ml, antigen testing across different concentrations (10, 12.5, 20, 50 µg/ml) showed peak changes at 12.5 µg/ml antigen, with a 1.186 nm shift and 0.503 dB loss. The sensor exhibited a wavelength sensitivity of 0.095 nm/µg/ml, indicating its high sensitivity and potential in gastric cancer classification, diagnosis, and treatment. This research concludes that the D-shaped fiber sensor is an effective and sensitive tool for detecting G-17 antigen levels, presenting a significant advancement in non-invasive gastric cancer diagnosis. Its quick response time and high sensitivity highlight its potential for broad biomedical applications, offering a new avenue for early cancer detection and improving patient prognosis. The success of this study opens the door to further exploration and implementation of fiber optic sensors in clinical settings, marking a significant step forward in the fight against gastric cancer.

Immunosensing for Early Detection of Rheumatoid Arthritis Biomarkers: Anti-Cyclic Citrullinated Peptide Antibodies Based on Tilted-Fiber Bragg Grating Biosensor.

Rheumatoid arthritis (RA) is regarded as a chronic, immune-mediated disease that leads to the damage of various types of immune cells and signal networks, followed by inappropriate tissue repair and organ damage. RA is primarily manifested in the joints, but also manifests in the lungs and the vascular system. This study developed a method for the in vitro detection of RA through cyclic citrullinated peptide (CCP) antibodies and antigens. The diameter of a tilted-fiber Bragg grating (TFBG) biosensor was etched to 50 µm and then bonded with CCP antigens and antibodies. The small variations in the external refractive index and the optical fiber cladding were measured. The results indicated that the self-assembled layer of the TFBG biosensor was capable of detecting pre- and post-immune CCP antigen and CCP peptide concentrations within four minutes. A minimum CCP concentration of 1 ng/mL was detected with this method. This method is characterized by the sensor's specificity, ability to detect CCP reactions, user-friendliness, and lack of requirement for professional analytical skills, as the detections are carried out by simply loading and releasing the test samples onto the platform. This study provides a novel approach to medical immunosensing analysis and detection. Although the results for the detection of different concentrations of CCP antigen are not yet clear, it was possible to prove the concept that the biosensor is feasible even if the measurement is not easy and accurate at this stage. Further study and improvement are required.

Application of Self-Assembled Polyarylether Substrate in Flexible Organic Light-Emitting Diodes.

The structure used in this study is as follows: substrate/PMMA/ZnS/Ag/MoO3/NPB/Alq3/LiF/Al. Here, PMMA serves as the surface flattening layer, ZnS/Ag/MoO3 as the anode, NPB as the hole injection layer, Alq3 as the emitting layer, LiF as the electron injection layer, and aluminum as the cathode. The properties of the devices with different substrates were investigated using P4 and glass, developed in the laboratory, as well as commercially available PET. After film formation, P4 creates holes on the surface. The light field distribution of the device was calculated at wavelengths of 480 nm, 550 nm, and 620 nm using optical simulation. It was found that this microstructure contributes to light extraction. The maximum brightness, external quantum efficiency, and current efficiency of the device at a P4 thickness of 2.6 µm were 72,500 cd/m2, 1.69%, and 5.68 cd/A, respectively. However, the maximum brightness of the same structure with PET (130 µm) was 9500 cd/m2. The microstructure of the P4 substrate was found to contribute to the excellent device performance through analysis of the AFM surface morphology, film resistance, and optical simulation results. The holes formed by the P4 substrate were created solely by spin-coating the material and then placing it on a heating plate to dry, without any special processing. To confirm the reproducibility of the naturally formed holes, devices were fabricated again with three different emitting layer thicknesses. The maximum brightness, external quantum efficiency, and current efficiency of the device at an Alq3 thickness of 55 nm were 93,400 cd/m2, 1.7%, and 5.6 cd/A, respectively.

A bipolar host material for the construction of triplet-energy level for white phosphorescent organic light emitting diodes.

Efficient white lighting sources based on phosphorescent organic light emitting diodes (PhOLEDs) have been predicted as the next generation of highly efficient general illumination systems. This study proposed a novel host material, CzppT, featuring the characteristics of bipolarity while possessing electron-withdrawing pyridine and electron-donating carbazole groups in the hexaphenylbenzene core, suitable for use in both blue and white PhOLEDs. The CzppT possesses a high triplet energy level and thermally activated delayed fluorescence stable which is confirmed by the high value of T d (480 °C). The effect of the emission layer deposition method on the characteristics of the device was studied in the dicarbazole derivative fabricated in a hole and electron-only device to ensure the bipolarity of CzppT. A blue PhOLED device exhibited a maximum external quantum efficiency of 11.0% with CIE coordinates (x, y) of (0.18, 0.41). Moreover, a white PhOLED device doped with a dye has a maximum external quantum efficiency of 11.3%, and CIE coordinates (x, y) of (0.32, 0.36). These results demonstrate that the hexaphenylbenzene derivative was conveniently synthesized with bipolarity and hole- and electron-transporting ability and high triplet energy level. Moreover, as a host material, it is expected to be applied to bipolar, high EL efficiency OLEDs in the future.

Efficiency Analysis of Fuel Cell Components with Ionic Poly-Arylether Composite Membrane.

We use polyethylene glycol as an additive to explore how the hydrogen bonding of this additive changes the properties of SA8 blended sulfonated polyetheretherketone (SPEEK) composite films. We mixed a 5%wt polyethylene glycol solution into a 12.5%wt SA8 solution, and then prepared a film with a total weight of 40 g at a ratio of 1:99. The SA8 (PEG) solution was prepared and then mixed with 5%wt SPEEK solution, and a film-forming solution with a total weight of 8g in different mixing ratios was created. Polyethylene glycol (PEG) was mixed into the sulfonated polyarylether polymer SA8 to form physical cross-linking. Therefore, the sulfonated polyether ether ketone SPEEK was mixed in, and it exhibited good thermal stability and dimensional stability. However, there was some decrease in proton conductivity as the proportion of SPEEK increased. Although SPEEK mixed with sulfonated polymer reduces the proton conductivity, the physical cross-linking of PEG can improve the proton conductivity of the composite membrane, and adding SPEEK can not only solve the problem of the high sulfonation film swelling phenomenon, it can also improve the dimensional stability of the film through the hydrogen bonding force of PEG and obtain a composite film with excellent properties.

Electric Field-Assisted Filling of Sulfonated Polymers in ePTFE Backing Material for Fuel Cell.

This study fabricated a composite ePTFE-backed proton-exchange membrane by filling the pores on the ePTFE backing with sulfonated polyarylene ethers through an externally supplied electric field. The morphology changes were observed under an SEM. The results suggested that the application of an electric field had led to the effective filling of pores by polymers. In addition, the composite membrane featured good dimensional stability and swelling ratio, and its water uptake, proton conductivity and component efficiency increased with voltage. It is found in this study that the external application of an electric field resulted in the effective filling of pores in the ePTFE by sulfonated polyarylene ether polymers and, thus, an improved composite membrane performance.

Ionomer Membranes Produced from Hexaarylbenzene-Based Partially Fluorinated Poly(arylene ether) Blends for Proton Exchange Membrane Fuel Cells.

In this study, a series of high molecular weight ionomers of hexaarylbenzene- and fluorene-based poly(arylene ether)s were synthesized conveniently through condensation and post-sulfonation modification. The use a of blending method might increase the stacking density of chains and affect the formation both of interchain and intrachain proton transfer clusters. Multiscale phase separation caused by the dissolution and compatibility differences of blend ionomer in high-boiling-point solvents was examined through analysis and simulations. The blend membranes produced in this study exhibited a high proton conductivity of 206.4 mS cm−1 at 80 °C (increased from 182.6 mS cm−1 for precursor membranes), excellent thermal resistance (decomposition temperature > 200 °C), and suitable mechanical properties with a tensile strength of 73.8−77.4 MPa. As a proton exchange membrane for fuel cell applications, it exhibits an excellent power efficiency of approximately 1.3 W cm−2. Thus, the ionomer membranes have strong potential for use in proton exchange membrane fuel cells and other electrochemical applications.

A U-Shaped Optical Fiber Temperature Sensor Coated with Electrospinning Polyvinyl Alcohol Nanofibers: Simulation and Experiment.

This study describes the fabrication of an electrospun, U-shaped optical fiber sensor for temperature measurements. The sensor is based on single mode fibers and was fabricated into a U-shaped optical fiber sensor through flame heating. This study applied electrospinning to coat PVA, a polymer, onto the sensor layer to reduce its sensitivity to humidity. The sensor is used to measure temperature variations ranging from 30 °C to 100 °C. The objectives of this study were to analyze the sensitivity variation of the sensor with different sensor layer thicknesses resulting from different electrospinning durations, as well as to simulate the wavelength signals generated at different electrospinning durations using COMSOL. The results revealed that the maximum wavelength sensitivity, transmission loss sensitivity, and linearity of the sensor were 25 dBm/°C, 70 pm/°C, and 0.956, respectively. Longer electrospinning durations resulted in thicker sensor layers and higher sensor sensitivity, that wavelength sensitivity of the sensor increased by 42%.

U-Shaped Optical Fiber Probes Coated with Electrically Doped GQDs for Humidity Measurements.

The influence of the bending radius on the sensitivity of the graphene quantum dots (GQDs)-coated probe is experimentally investigated for a U-shaped probe. The fiber is bent into a U shape using the optic fiber flame heating method, and the optic fiber is enclosed in a glass tube to increase the stability of the probe. The surface of the U-shaped optical fiber was coated with electrospun fibers formed via electrospinning. Polymer materials doped with GQDs are applied to U-shaped optical fiber as humidity sensors. Graphene quantum dot nanofibers on the U-shaped optical fiber sensor to form a network structure of graphene quantum dots U-shape fiber sensor (GQDUS). The polymer network structure absorbs water molecules, which in turn affects the bending radius of the optical fiber, and changes the optical fiber spectrum. Graphene quantum dots provide optical enhancement benefits, which in turn increase the sensitivity of fiber optic sensors. The spectra monitoring system consists of an optical spectrum analyzer (OSA) and an amplified spontaneous emission (ASE). This system can be used to detect humidity changes between 20% RH and 80% RH in the chamber. Our results indicate promising applications for quantum dots probe sensors from electrospun nanofibers increasing sensitive environmental monitoring. As such, it could be of substantial value in optical sensors detection.

Highly Proton-Conducting Membranes Based on Poly(arylene ether)s with Densely Sulfonated and Partially Fluorinated Multiphenyl for Fuel Cell Applications.

Series of partially fluorinated sulfonated poly(arylene ether)s were synthesized through nucleophilic substitution polycondensation from three types of diols and superhydrophobic tetra-trifluoromethyl-substituted difluoro monomers with postsulfonation to obtain densely sulfonated ionomers. The membranes had similar ion exchange capacities of 2.92 ± 0.20 mmol g-1 and favorable mechanical properties (Young's moduli of 1.60-1.83 GPa). The membranes exhibited considerable dimensional stability (43.1-122.3% change in area and 42.1-61.5% change in thickness at 80 °C) and oxidative stability (~55.5%). The proton conductivity of the membranes, higher (174.3-301.8 mS cm-1) than that of Nafion 211 (123.8 mS cm-1), was the percent conducting volume corresponding to the water uptake. The membranes were observed to comprise isolated to tailed ionic clusters of size 15-45 nm and 3-8 nm, respectively, in transmission electron microscopy images. A fuel cell containing one such material exhibited high single-cell performance-a maximum power density of 1.32 W cm2 and current density of >1600 mA cm-2 at 0.6 V. The results indicate that the material is a candidate for proton exchange membranes in fuel cell applications.

Enhancement of the stability of chlorophyll using chlorophyll-encapsulated polycaprolactone microparticles based on droplet microfluidics.

Chlorophyll is a valuable bioactive compound, which is used as a natural food coloring agent and a photosensitizer for photodynamic therapy because of its antioxidant properties, antimutagenic ability, and near-infrared fluorescence. However, chlorophyll is unstable when it comes to retaining its antioxidant activity, when exposed to oxygen, high temperature, or light environments. To enhance the stability of chlorophyll, a polymer encapsulation method was proposed. Polycaprolactone (PCL) was employed to encapsulate the chlorophyll, and the particles size of the composites was controlled through droplet microfluidics. The composites (chlorophyll-encapsulated PCL particles) were characterized through UV-VIS spectrometry, SEM, optical microscopy, and light exposure. The particles were spherical, with diameters adjustable from 68 to 247 µm. Additionally, the chlorophyll-encapsulated PCL particles exhibited considerably prolonged chlorophyll stability. The solid microparticle is more convenient for storage and transportation, and have great potential for application in the food industry.

Long-Period Fiber Grating Sensor Based on a Conductive Polymer Functional Layer.

A temperature sensor was fabricated with a functional conductive poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coating on a long-period fiber grating (LPFG). The LPFG was fabricated by laser-assisted wet-chemical etching for controlling the grating depth of the LPFG after the treated surface of an optical fiber was inscribed by laser light. The functional conductive polymer acts as a temperature sustained sensing layer and enhances the grating depth of the LPFG sensor as a strain buffer at various temperatures. The sensor was subjected to three cycles of temperature measurement to investigate the sensor's wavelength shift and energy loss when exposed to temperatures between 30 and 100 °C. Results showed that the sensor's average wavelength sensitivity and its linearity were 0.052 nm/°C and 99%, respectively; average transmission sensitivity and linearity were 0.048 (dB/°C) and 95%, respectively.

Facile synthesis of highly tunable monodispersed calcium hydroxide composite particles by using a two-step ion exchange reaction.

"Calcium hydroxide [Ca(OH)2]" is a medicament frequently used for antimicrobial purposes in endodontic procedures, or it is used as a toxic-waste adsorbent in industry. Ca(OH)2 particles produced through conventional methods are size untunable and have a wide size distribution and polygonal shape. In this paper, a novel and facile approach involving template-mediated synthesis and two-step ion exchange is proposed for uniform size Ca(OH)2 composite particles generation. "Sodium-alginate (Na-alginate)" was used as a precursor, and monodisperse Na-alginate emulsions were formed through needle droplet or droplet microfluidic technology. After the first ion exchange step with the Ca2+ ions, "calcium-alginate (Ca-alginate)" particles were obtained. The Ca-alginate particles were intermediate reaction products and were designed to be the templates for ensuring the spherical shape and size of products. The OH- ions were used for the second ion exchange step to fabricate Ca(OH)2 composite particles. The results revealed that the Ca(OH)2 composite particles were size tunable, had a spherical shape, and were monodisperse (with a relative standard deviation of less than 8%). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay revealed that the Ca(OH)2 composite particles were potential biocompatible materials.

The after-effect of human theta burst stimulation is NMDA receptor dependent.

OBJECTIVE: To provide pharmacological evidence that the after-effects of theta burst stimulation (TBS) involve plasticity like changes in cortical synaptic connections, using the N-methyl-D-aspartate receptor antagonist memantine. METHODS: We performed a double blind, placebo-controlled study to evaluate the effect of memantine on the response of six healthy volunteers to TBS. We measured rest (RMT) and active (AMT) motor thresholds, and the amplitude of MEPs before and after continuous and intermittent TBS (cTBS/iTBS) after the administration of placebo or memantine. RESULTS: Memantine had no effect on RMT and AMT, while it blocked the suppressive effect of cTBS and the facilitatory effect of iTBS. CONCLUSIONS: The effects of iTBS and cTBS rely on NMDARs to produce after-effects in the motor cortex of conscious humans. SIGNIFICANCE: The NMDA dependency of the after-effects of TBS adds to the understanding of the underlying mechanism of TBS, and suggests that these after-effects are likely to involve plasticity like changes at synaptic connections in motor cortex.

Helium and methane sources and fluxes of shallow submarine hydrothermal plumes near the Tokara Islands, Southern Japan.

Shallow submarine volcanoes have been newly discovered near the Tokara Islands, which are situated at the volcanic front of the northern Ryukyu Arc in southern Japan. Here, we report for the first time the volatile geochemistry of shallow hydrothermal plumes, which were sampled using a CTD-RMS system after analyzing water column images collected by multi-beam echo sounder surveys. These surveys were performed during the research cruise KS-14-10 of the R/V Shinsei Maru in a region stretching from the Wakamiko Crater to the Tokara Islands. The 3He flux and methane flux in the investigated area are estimated to be (0.99-2.6) × 104 atoms/cm2/sec and 6-60 t/yr, respectively. The methane in the region of the Tokara Islands is a mix between abiotic methane similar to that found in the East Pacific Rise and thermogenic one. Methane at the Wakamiko Crater is of abiotic origin but affected by isotopic fractionation through rapid microbial oxidation. The helium isotopes suggest the presence of subduction-type mantle helium at the Wakamiko Crater, while a larger crustal component is found close to the Tokara Islands. This suggests that the Tokara Islands submarine volcanoes are a key feature of the transition zone between the volcanic front and the spreading back-arc basin.

A Spirobifluorene Derivative as a Single-Emitting Component for a Highly Efficient White Organic Electroluminescent Device.

We describe how the morphology, photoluminescence (PL), and electroluminescence properties of 2,2',7,7'-tetrakis(pyren-1-yl)-9,9'-spirobifluorene (TPSBF) are related to its film thickness and how, under optimized conditions, the three main PL emissions constitute a form of white light. We fabricated high-brightness, broad-spectrum, white-light organic light-emitting diodes, incorporating a single emission layer of the blue-light-emitting material TPSBF, which comprises four pyrene units linked to a spirobifluorene core. An organic light-emitting device with the configuration indium tin oxide (170 nm)/4,4',4''-tris[N-(2-naphthyl)-N-phenylamino]triphenylamine (15 nm)/4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (65 nm)/TPSBF (50 nm)/tris(8-hydroxyquinoline)aluminum (30 nm)/LiF (0.8 nm)/Al (200 nm) exhibited a broad-spectrum white emission with a maximum luminescence and current efficiency of 57 680 cd m-2 and 6.51 cd A-1 , respectively, and Commission International De l'Eclairage coordinates of (0.29,0.36).