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Porous TiO <sub/>2</sub> Nanotube Arrays for Drug Loading and Their Elution Sensing
摘要： Porous TiO2 nanotube arrays have been attracting much attention as optical sensing layers and surface layers of dental implants because they are stable in acid and biocompatible. To use them as the optical sensing layers, TiO2 nanotube arrays with various structures were fabricated and obtained an optimized microstructure at 50 V, 50 min and 0.5 wt% of NH4F, 7.4 vol% deionized water in ethylene glycol. TiO2 nanotube arrays which had diameters of ～73.54 nm and lengths of ～3.39 μm showed the best sensing performance. A Ti implant was also anodized at 60 V for 4 hr in an ethylene glycol electrolyte and TiO2 nanotube arrays showed the pore diameter of 156.01 nm and the thickness of 6.87 μm. Recombinant human bone morphogenetic protein-2 (rhBMP-2), isobutylphenyl propionic acid, and sodium alendronate were loaded into the TiO2 nanotube arrays on the surface of the Ti implant. For elution of these drugs, optical thickness changes of 2.4 nm, 3.5 nm and 3.1 nm were respectively observed for about 2.2 hr, 3.6 hr and 3.1 hr. The TiO2 nanotube arrays were useful for drug loading and their elution interferometric sensing.
关键词： Dental Implant,Porous TiO2 Nanotube Arrays,Interferometric Sensor,Isobutylphenyl Propionic Acid,Drug Delivery,rhBMP-2,Sodium Alendronate
更新于2025-09-04 15:30:14
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TiO <sub/>2</sub> :Sm <sup>3+</sup> based luminescent oxygen sensitive probes in LDPE packaging material
摘要： In present work it was attempted to prepare luminescent TiO2:Sm3+ microprobes embedded into low density polyethylene (LDPE) films for real-time non-intrusive detection of oxygen contamination in plastic film of food packages with a long term goal of streamlining the quality control mechanisms in food packaging process. The luminescence of TiO2:Sm3+ has previously been reported to be a usable for optical sensing of O2 and other gases [1]. In current work we also show that its thermal stability makes it especially suitable for thermo polymer industry as it can withstand required thermal treatments encountered in different polymer processing stages without losing its ability to function as an O2 probe. Sol–gel-prepared TiO2:Sm3+ microparticles were embedded into LDPE by direct mixing [2] and hot pressing the polymer in molten state. The optical response of the doped films to various O2 ambient concentrations are reported in comparison to pristine TiO2:Sm3+ powder. The shortcomings in the sensor performance due to poor oxide particle size control must be paid attention in the future.
关键词： extrusion,LDPE,Sm3+,oxygen sensor,TiO2
更新于2025-09-04 15:30:14
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Potential of UAV-Based Active Sensing for Monitoring Rice Leaf Nitrogen Status
摘要： Unmanned aerial vehicle (UAV) based active canopy sensors can serve as a promising sensing solution for the estimation of crop nitrogen (N) status with great applicability and ?exibility. This study was endeavored to determine the feasibility of UAV-based active sensing to monitor the leaf N status of rice (Oryza sativa L.) and to examine the transferability of handheld-based predictive models to UAV-based active sensing. In this 3-year multi-locational study, varied N-rates (0–405 kg N ha?1) ?eld experiments were conducted using ?ve rice varieties. Plant samples and sensing data were collected at critical growth stages for growth analysis and monitoring. The portable active canopy sensor RapidSCAN CS-45 with red, red edge, and near infrared wavebands was used in handheld mode and aerial mode on a gimbal under a multi-rotor UAV. The results showed the great potential of UAV-based active sensing for monitoring rice leaf N status. The vegetation index-based regression models were built and evaluated based on Akaike information criterion and independent validation to predict rice leaf dry matter, leaf area index, and leaf N accumulation. Vegetation indices composed of near-infrared and red edge bands (NDRE or RERVI) acquired at a 1.5 m aviation height had a good performance for the practical application. Future studies are needed on the proper operation mode and means for precision N management with this system.
关键词： RapidSCAN,ultra low-level airborne,active canopy sensor,sensing distance evaluation,red edge
更新于2025-09-04 15:30:14
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Enhanced Sensing Performance of Integrated Gas Sensor Devices
摘要： Semiconducting metal oxide (SMO) gas sensors, dedicated to wearable devices were designed, fabricated, and characterized in terms of power consumption, thermal distribution, and sensing capability. The sensors demonstrate a sensitivity down to ppb-level VOC concentrations at a low power consumption of 10.5 mW. To further enhance the baseline stability and sensing response characteristics at low power consumption, a new sensor structure is proposed. The design implements novel aspects in terms of fabrication and microheater geometry, leading to improved sensor performance which enables new applications for SMO gas sensors. In this work, two designs were analyzed using experimental characterization and simulation. The results of the analyses of the two sensors are comparatively reported.
关键词： microheater,electo-thermal simulation,gas sensor,semiconducting metal oxide
更新于2025-09-04 15:30:14
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Construction of a Luminogen Exhibiting High Contrast and Multicolored Emission Switching through Combination of a Bulky Conjugation Core and Toly Groups
摘要： Stimuli responsive luminogens may find application in highly sensitive sensors, memories and security inks. However, few examples exhibiting both high contrast and multi-colored emission switching have been reported due to the absence of molecular design strategy. Through combination of large conjugation core and peripheral phenyl rings, we obtained ditolyldibenzofulvene (1). Luminogen 1 is AIE active and exhibits tetracolored emission depending on its morphology. Its three single crystals emit blue, yellow and dark orange light upon excitation, exhibiting a maximal emission of 461 nm, 545 nm and 586 nm, respectively, and its amorphous solid emits at 557 nm. All the four aggregates exhibit enhanced emission intensity at lower temperature, but only the orange emissive crystals exhibit blue-shifted emission. The emission of 1 can be switched reversibly between any two of the four states through morphology tuning. Finally, the potential application of 1 in optical data storage was also investigated.
关键词： AIE,fluorescence,sensor,mechanochromic luminescence,stimuli responsive luminogen
更新于2025-09-04 15:30:14
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Improving Color Accuracy of Colorimetric Sensors
摘要： Accurate measurements of re?ectance and color require spectrophotometers with prices often exceeding $3000. Recently, new “color instruments” became available with much lower prices, thanks to the availability of inexpensive colorimetric sensors. We investigated the Node+ChromaPro and the Color Muse, launched in 2015 and 2016 by Variable Inc. Both instruments are colorimeters, combining a colorimetric sensor with LED lighting. We investigated color accuracy compared to a high-end spectrophotometer from BYK Gardner. With different sets of samples we ?nd for the Node an average value of dECMC (1:1) = 1.50, and a maximum of 7.86, when comparing with the 45? geometry of the spectrophotometer. Utilizing measurement data on the Spectral Power Distributions of the LEDs, we developed three methods to improve color accuracy as compared to the spectrophotometer data. We used these methods on different sets of samples with various degrees of gloss, both for training the models underlying the methods and for independent tests of model accuracy. Average color accuracy of the Node+ChromaPro improves from dECMC (1:1) = 1.82 to 1.16 with respect to spectrophotometer data. The percentage of samples with dECMC (1:1) < 1.0 increases from 30.9% (uncorrected) to 64%. With the improved color accuracy, these sensors become useful for many more applications.
关键词： measurement accuracy,colorimetric sensor
更新于2025-09-04 15:30:14
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Fluorescent Chemosensor for Quantitation of Multiple Atmospheric Gases
摘要： Recently, the sensing and monitoring of gases from ambient as well as industrial sources has gained a great importance in order to ensure occupational hygiene, public health, and societal welfare. The development of new technologies for visualizing and detecting gases at trace levels is imperative for various applications. There exist several established traditional methods to detect different gases. In this article, we review the latest trends in the area of fluorescence sensing of gas molecules, which is a high sensitivity technique with minimum or negligible interferences. The gas sensors fabricated with the use of fluorescent nanoparticles as detecting elements possess special feature, like high surface-to-volume ratios, ultra sensitivity, enhanced selectivity, cost effectiveness, and fast response. The inherent properties of the related systems, e.g. a large fluorescence lifetime, nanoscale particle size and a tunable zeta potential, make it possible to devise fluorescent sensors with an attractive pathway of fluorescence ‘off–on’. Several fluorimetric methods are known to detect specific gases from the atmospheric gaseous samples with satisfactory detection results. Modern fluorescent gas sensors are did not cause interference from the co-pollutants thus making the fluorimetric sensing process to be quantitative as well as specific.
关键词： Atmospheric environmental sample,Fluorescent gas sensor,Job’s plot,Fluorescent organic nanoparticles,Analytical method,Fluorescence lifetime
更新于2025-09-04 15:30:14
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PHIPS–HALO: the airborne Particle Habit Imaging and Polar Scattering probe – Part 1: Design and operation
摘要： The number and shape of ice crystals present in mixed-phase and ice clouds influence the radiation properties, precipitation occurrence and lifetime of these clouds. Since clouds play a major role in the climate system, influencing the energy budget by scattering sunlight and absorbing heat radiation from the earth, it is necessary to investigate the optical and microphysical properties of cloud particles particularly in situ. The relationship between the microphysics and the single scattering properties of cloud particles is usually obtained by modelling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. There is a demand to obtain both information correspondently and simultaneously for individual cloud particles in their natural environment. For evaluating the average scattering phase function as a function of ice particle habit and crystal complexity, in situ measurements are required. To this end we have developed a novel airborne optical sensor (PHIPS-HALO) to measure the optical properties and the corresponding microphysical parameters of individual cloud particles simultaneously. PHIPS-HALO has been tested in the AIDA cloud simulation chamber and deployed in mountain stations as well as research aircraft (HALO and Polar 6). It is a successive version of the laboratory prototype instrument PHIPS-AIDA. In this paper we present the detailed design of PHIPS-HALO, including the detection mechanism, optical design, mechanical construction and aerodynamic characterization.
关键词： mixed-phase clouds,PHIPS-HALO,precipitation,ice crystals,ice clouds,optical properties,radiation properties,climate system,microphysical properties,airborne optical sensor
更新于2025-09-04 15:30:14
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An Optical pH Sensor Based on Diazaoxatriangulenium and Isopropyl‐Bridged Diazatriangulenium Covalently Bound in a Composite Sol–Gel
摘要： Optical pH sensing is still in its infancy due to lack of highly stable pH responsive dyes. The triangulenium fluorophores show remarkable photostability and have been demonstrated as the responsive dye in an intensity based ratiometric optical pH sensor using a fiber optical sensor hardware. Here, an optical pH sensor is reported where both the responsive dye and the reference dye are from the triangulenium family using free form optics for the hardware platform. A full spectrometer-based sensor system consisting of sensor chemistry, hardware, and software is presented.
关键词： fluorescent materials,optical sensors,sensor systems,chemosensors,pH optodes
更新于2025-09-04 15:30:14
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Specific electron-transfer and surface plasmon resonance integrated boosting visible-light photoelectrochemical sensor for 4-chlorophenol
摘要： Emerging analytical technologies are being developed to provide advanced methods for monitoring 4-chlorophenol (4-CP) in the environment. Herein, a label-free, sensitive, and rapid photoelectrochemical (PEC) 4-CP detection system was constructed based on ternary composites of Ag nanoparticles, graphitic carbon nitride (GCN) and carbon spheres (CS) (Ag/GCN/CS). The proposed ternary composites were synthesized by a simple hydrothermal method. In this process, ascorbic acid (AA) played a crucial role in reducing Ag+ to metallic Ag, and provided a carbon source for CS. Due to synergistic promotion by the surface plasmon resonance (SPR) effect of Ag nanoparticles and electron-transfer behavior of CS, the ternary composites exhibited a broad visible light response and fast charge transfer, leading to a tremendously enhanced PEC response. Based on the promotion of the PEC response, a PEC sensor for 4-CP was designed by detecting the photocurrent signals of the PEC electrode after adding 4-CP to solution. Under optimal conditions, the PEC sensor exhibited a wide linear range for 4-CP from 16 to 1104 ng mL–1, with a limit of detection (LOD) of 5.33 ng mL–1. In particular, the present work may provide assist in better understanding the synergistic effect between the SPR effect of Ag nanoparticles and electron-transfer properties of CS. The results can also be applied to other PEC and photocatalytic systems in conjunction with high-performance photoactive materials.
关键词： PEC sensor,Carbon materials,Electron-transfer,SPR,Ternary composite
更新于2025-09-04 15:30:14