Strong Anti-interference Ability Research Articles

Synthesis and application of a novel fluorescent probe based on benzothiazole for detection of hydrazine in real samples

ABSTRACT A novel fluorescence enhancement type probe 2-(1, 3-benzothiazol-2-yl)-5-(diethylamino)phenyl thiophene-2-carboxylate (PTN) for the detection of hydrazine (N2H4) was designed and synthesised. The fluorescence of the probe PTN solution increased dramatically upon the addition of N2H4 and its appearance changed from nearly colourless to dazzling blue. The simple structure and readily available fluorescent probe provide a novel approach for the quantitative detection of N2H4 in the linear range from 0 to 37.5 μM, with a detection limit down to 56 nM, fast response (within 5 min), strong anti-interference ability, easy operation (test paper), and a wide range of pH from 6 to 10. Furthermore, the probe PTN was able to detect N2H4 in actual water samples and image the exogenous N2H4 signal in colorimetric test strips and living zebrafish.

An Imidazo[1, 2-a]Pyridine Based Fluorescent Probe for the Continuous "on-off-on" Detection of Fe3+ and F.

An "on-off-on" fluorescent probe LK was synthesized from 2-benzoylpyridine and o-vanillin, which could sequentially detect Fe3+ and F- in DMSO/H2O solutions (v/v = 1/1, HEPES buffer, 1.0 mM, pH 7.0) with large Stokes shift (178nm). LK exhibited not only high selectivity and sensitivity towards Fe3+ and F-, but also strong anti-interference ability to other ions. LK was coordinated with Fe3+ at a ratio of 2:1, with a binding constant (Ka) of 1.3 × 104 M- 1. The detection limits for Fe3+ and F- were 6.9 × 10- 8 M and 3.0 × 10- 7 M, respectively. Due to its excellent sensing performance, LK was successfully applied in actual water samples and test papers for the detection of Fe3+ and F-.

Quasi-distributed quartz enhanced photoacoustic spectroscopy sensing based on hollow waveguide micropores.

In this Letter, a quasi-distributed quartz enhanced photoacoustic spectroscopy (QEPAS) gas sensing system based on hollow waveguide micropores (HWGMP) was reported for the first time, to the best of our knowledge. Three micropores were developed on the HWG to achieve distributed detection units. Three self-designed quartz tuning forks (QTFs) with low resonant frequency of 8.7 kHz were selected as the acoustic wave transducer to improve the detection performance. Compared with micro-nano fiber evanescent wave (FEW) QEPAS, the HWGMP-QEPAS sensor has advantages such as strong anti-interference ability, low loss, and low cost. Acetylene (C2H2) was selected as the target gas to verify the characteristics of the reported sensor. The experimental results showed that the three QTFs almost had the same sensing ability and possessed an excellent linear concentration response to C2H2. The minimum detection limits (MDLs) for the three QTFs were determined as 68.90, 68.31, and 66.62 ppm, respectively. Allan deviation analysis indicated that the system had good long-term stability, and the MDL can be improved below 3 ppm in an average time of 1000 s.

Research on electro-hydraulic position servo synchronous control system based on adaptive robust control

A control method combining adaptive robust control with cross-coupling control is designed to address the issues of model uncertainty, nonlinear friction, and external interference in electro-hydraulic servo systems. We have established a nonlinear model of the system and designed an adaptive robust controller. Further simulation studies have shown that the control method designed in this paper has better control performance and stronger anti-interference ability than PID control and still has good control performance under continuous interference.

Less interference fluorescence analytical strategy: Bridging substance-triggered ratiometric sensor with convenient preparation and application

High interference and narrow application range are key of bottleneck of recent fluorescence analysis methods, which limit their wide application in the sensing field. Therefore, to overcome these disadvantages, a ratiometric fluorescence sensing system utilizing berberine (BER) and silver nanoclusters protected by dihydrolipoic acid (DHLA-AgNCs) was constructed for the first time in this work, to achieve determination of BER and daunorubicin (Dau). BER aqueous solution (non-planar conformation) has no fluorescence emission. When it was mixed with DHLA-AgNCs, the conformation of BER became planar, producing fluorescence emission at 515 nm besides the fluorescence emission peak of DHLA-AgNCs at 653 nm. With the increase of BER concentration added in system, the fluorescence intensity of BER (planar conformation) at 515 nm increased obviously and the fluorescence intensity of DHLA-AgNCs decreased slightly. Therefore, the dual emission fluorescence sensing system was constructed based on a fluorescence substance and non fluorescence substance, to achieve determination of BER. Meanwhile, based on the bridging effect of BER and fluorescence resonance energy transfer effect from Dau, the altering of two peaks intensity was utilized to achieve determination of Dau. Thus, this dual emission sensing system can not only be used for fluorescence analysis of BER and its analogues, but also based on the bridging effect of BER, allowing the determination of Dau and its analogues that could not be directly measured with silver nanoclusters, expanding the application range of traditional dual emission detection systems. Meanwhile, this system has strong anti-interference ability and low toxicity to the human body and less pollution to the sample and environment. This provides a new direction and universal research strategy for the construction of new fluorescence sensing systems in the future for the analysis of target substances that cannot be directly detected with conventional fluorescence analysis methods.

Development of a biophotonic fiber sensor using direct-taper and anti-taper techniques with seven-core and four-core fiber for the detection of doxorubicin in cancer treatment

Doxorubicin (DOX) is an important drug for cancer treatment, but its clinical application is limited due to its toxicity and side effects. Therefore, detecting the concentration of DOX during treatment is crucial for enhancing efficacy and reducing side effects. In this study, the authors developed a biophotonic fiber sensor based on localized surface plasmon resonance (LSPR) with the multimode fiber (MMF)-four core fiber (FCF)-seven core fiber (SCF)-MMF-based direct-taper and anti-taper structures for the specific detection of DOX. Compared to other detection methods, it has the advantages of high sensitivity, low cost, and strong anti-interference ability. In this experiment, multi-walled carbon nanotubes (MWCNTs), cerium-oxide nanorods (CeO2-NRs), and gold nanoparticles (AuNPs) were immobilized on the probe surface to enhance the sensor's biocompatibility. MWCNTs and CeO2-NRs provided more binding sites for the fixation of AuNPs. By immobilizing AuNPs on the surface, the LSPR was stimulated by the evanescent field to detect DOX. The sensor surface was functionalized with DOX aptamers for specific detection, enhancing its specificity. The experiments demonstrated that within a linear detection range of 0-10 µM, the sensitivity of the sensor is 0.77 nm/µM, and the limit of detection (LoD) is 0.42 µM. Additionally, the probe's repeatability, reproducibility, stability, and selectivity were evaluated, indicating that the probe has high potential for detecting DOX during cancer treatment.

A Fluorescent Probe for Hg2+ Specific Recognition Based on Xanthene and its Application in Food Detection and Cell Imaging.

The mercury-loving unit aminothiourea was introduced into the xanthene fluorophore to synthesized the probe molecule NXH. NXH has a specific response to Hg2+, and with the addition of (0 ~ 50 µM) Hg2+, the fluorescence intensity of the probe solution was quenched from 2352 a.u. to about 308 a.u. NXH exhibited excellent detection performance of high sensitivity (LOD = 96.3 nM), real-time response (105s), wide pH range (2.1 ~ 9.3), and strong anti-interference ability for Hg2+. At the same time, NXH has wide range of applications for Hg2+ detection, which can fluorescence imaging of Hg2+ in Hela cells and tea samples, and can also be made into Hg2+ detection test paper.

Construction and regulation of high active sites in montmorillonite composite catalyst for the removal of ofloxacin via persulfate activation

In this study, ionic liquids (ILs) were used as organic modifiers by introducing montmorillonite nanolayers containing potential C and N active sites between the montmorillonite nanolayers. Organically modified montmorillonite (ILs-Mt-p) was further prepared by high-temperature pyrolysis under N2 and used for the removal of ofloxacin (OFL) by activated peroxymonosulfate (PMS). Combined with XPS and other characterization analyses, it was found that the catalyst materials prepared from different organic modifiers had similar surface functional groups and graphitized structures, but contained differences in the types and numbers of C and N active sites. The catalyst (3CPC-Mt-p) obtained after pyrolysis of montmorillonite modified with cetylpyridinium chloride (CPC) had optimal catalytic performance, in which graphitic C, graphitic N, and carbonyl group (CO) could synergistically promote the activation of PMS by electron transfer, and 77.3 % of OFL could be removed within 60 min. The effects of OFL concentration, initial pH, and anions on the effects of OFL removal by the 3CPC-Mt-p/PMS system were further investigated. Satisfactory degradation results were obtained over a wide pH range. Cl− promoted the system to degrade OFL, while the presence of SO42−, H2PO4− and HA showed some inhibition, but overall the 3CPC-Mt-p catalysts had a strong anti-interference ability, showing good application prospects. The quenching experiments and EPR tests showed that O2−- and 1O2 in the 3CPC-Mt-p/PMS system were the main reactive oxygen species for the degradation of OFL, and •OH was also involved in the reaction. This study provides ideas for the construction and modulation of active sites in mineral materials such as montmorillonite and broadens the application of montmorillonite composite catalysts in advanced oxidation processes for the treatment of antibiotic wastewater.

Mechanistic investigation of Pb2+ adsorption on biochar modified with sodium alginate composite zeolitic imidazolate framework-8.

For the serious situation of heavy metal pollution, the use of cheap, clean, and efficient biochar to immobilize heavy metals is a good treatment method. In this paper, SA@ZIF-8/BC was prepared for the adsorption of Pb2+ in solution using sodium alginate (SA) and zeolitic imidazolate framework-8 (ZIF-8)modified corn cob biochar. The results showed that the specific surface area of modified biochar was greatly improved, with good adsorption capacity for Pb2+, strong anti-interference ability, and good economy. At the optimal adsorption pH of 5, the adsorption model of Pb2+ by SA@ZIF-8/BC was more consistent with the pseudo-second-order kinetic model and Langmuir isotherm model. This indicates that the adsorption of Pb2+ by SA@ZIF-8/BC is chemisorption and monolayer adsorption. The maximum adsorption of modified biochar was 300mgg-1, which was 2.38 times higher than that of before modified BC (126mgg-1). The shift in binding energy of functional groups before and after adsorption of SA@ZIF-8/BC was studied by XPS, and it was found that hydroxyl and carboxyl groups played an important role in the adsorption of Pb2+. It was demonstrated that this novel adsorbent can be effectively used for the treatment of Pb pollution in wastewater.

A rhodamine 110 loaded and molecularly imprinted polymers coated millipore filter membrane-based fluorescent sensor for sensitive and selective caffeic acid detection

In this paper, a rhodamine 110 (R110) loaded and molecularly imprinted polymers (MIPs) coated microporous membrane-based fluorescent sensor has been constructed. The morphology, structure and performance of the sensor during the preparation process are characterized by SEM, FT-IR, UV–vis, fluorescene, BET and HPLC. The sensor retains the characteristic fluorescence emission peaks of R110, and the fluorescence changes to different concentrations of caffeicacid (CA) in the range of 0.01–200 µmol/L can obtain a good linear correlation with the detection limit of 3.3 nmol/L (3σ). The sensor possesses the advantages of easy preparation, simple operation, high stability, good sensitivity and selectivity, and strong anti-interference ability in the detecting of CA in herbal tea, exhibiting excellent potential application value in CA detection in different foods.

Ratiometric peptide-based fluorescent probe with large Stokes shift for detection of Hg2+ and S2− and its applications in cells imaging and smartphone-assisted recognition

In this work, a new ratiometric fluorescent probe DKA was synthesized based on the double sides of lysine backbone conjugated with alanine and dansyl groups. DKA exhibited fluorescence ratiometric response for Hg2+ with high sensitivity (13.4 nM), specific selectivity (only Hg2+), strong anti-interference ability (no interference), fast recognition (within 60 s) and wide pH range (5–10). The stoichiometry of binding of DKA and Hg2+ was determined to be 1:1 via Job’s plot, ESI-HRMS and 1HNMR titration analysis. Subsequently, the in situ formation of DKA-Hg2+ complex was used for highly selective detection of S2− as a novel fluorescence “on–off” probe, and the lowest detection limit for S2− was 12.9 nM. In addition, DKA possessed excellent cells permeation and low toxicity, and fluorescence imaging of Hg2+ and S2− was performed in living Hacat cells. Most importantly, the digital imaging using a smartphone color recognition APP indicated that DKA could semi-quantitatively and visually detected Hg2+ and S2− without expensive equipment.

A simulated fusion localization algorithm with adaptive error covariance matrix for closed corridor seamless positioning

Due to the blocking and reflection of buildings, the received Beidou satellite navigation signal (BDS) in the closed corridor will be getting weaker, which results in poor positioning accuracy or positioning failure. Introducing Ultra-Wide Band (UWB) positioning technology and establishing BDS/UWB integrated positioning system is an effective method to achieve seamless positioning. The positioning accuracy obtained by the Least Square-Kalman Filter (LS-KF) algorithm is below m level. However, the prior error covariance matrix of the KF correction process is easily contaminated, which affects the proportion of system observations and state prediction values to the optimal position estimation. A LS-KF fusion positioning algorithm based on adaptive error covariance matrix is proposed, the algorithm adjusts the state prior error covariance matrix by constructing an adaptive factor, improves the Kalman gain and the optimal estimation of the position, balances the trust of the filter estimation value to the observation value and the state prediction value of the integrated positioning system. Theoretical analysis and experimental results show that compared with LS-KF, EKF, UKF and improved LS-KF algorithm, the proposed LS-AKF algorithm not only has higher positioning accuracy, stronger anti-interference ability, but also has faster convergence speed.

Dynamic estimation method for pulsar periods based on photon energy distribution folding and image template matching

The accuracy of the pulsar period estimation directly affects the restoration effect of the signal profile. A more accurate pulsar profile will help improve the accuracy of pulsar delay estimation and thereby improve the performance of X-ray pulsar navigation. This paper proposes a pulsar period estimation method based on photon energy distribution folding and image template matching (PETM). This method uses the probability distribution information of photon energy for weighted epoch folding. The one-dimensional (1D) profile information was converted into two-dimensional (2D) image information through reverse space-filling curve (SFC) encoding. Then, a feature matching was performed between the target structure and the template structure. At the same time, the criterion of Pearson correlation coefficient (PCC) was used to quantitatively evaluate the matching effect to estimate the optimal period. The simulation results show that the period estimation accuracy of the PETM method is significantly improved, as compared with the traditional \( method. This work also analyzes the folding effect based on the photon energy distribution model and conducts simulation experiments and comparisons on influencing factors, such as noise interference and data quality. At the same time, we also specifically demonstrated the effectiveness of the PETM method for the glitch phenomenon (i.e., a sudden change in period) of pulsar periods. Finally, we also used China's XPNAV-1 satellite to conduct experiments and analysis of the actual observation data of PSR B0531+21 pulsar within a fixed period of time. The results show that the period estimation accuracy of this method is 4.8190$ns$, which is 50.23<!PCT!> higher than the traditional \( method. The method proposed in this article has the advantages of high estimation accuracy, stable estimation performance, strong anti-interference ability, and excellent dynamic period estimation performance. Therefore, it can further improve the navigation performance of X-ray pulsars.

Magnetic levitation system control research based on improved linear active disturbance rejection

In this study, we propose an improved linear active disturbance rejection control (I-LADRC) method to achieve stable suspension of magnetic levitation balls. This method can not only solve the overshoot problem but also enhance the anti-interference capability. The control algorithm is designed, and the convergence of the control system is verified by derivation. To verify the effectiveness of the proposed control algorithm, we conduct simulation experiments and analyze the dynamic performance, tracking effect, and anti-interference ability of four controllers: sliding mode control (SMC), LADRC, longitudinal error-LADRC (LE-LADRC), and I-LADRC. Simulation results show that I-LADRC outperforms SMC, LADRC, and LE-LADRC regarding tracking effect and anti-interference ability. We also experimentally verify the control performance of I-LADRC. The experimental results show that I-LADRC has strong anti-interference ability and robust performance, which is 100% and 50% higher than LADRC and LE-LADRC, and has good dynamic performance, which verifies the effectiveness of the simulation experiment, which exhibits better robustness and dynamic performance.

A specific dual-locked fluorescence probe to visualize the dynamic changes of lipid droplets and hypochlorous acid in inflammation

Inflammation is a key factor leading to the occurrence and development of many diseases, both lipid droplets (LDs) and hypochlorous acid (HClO/ClO-) are regarded as the important biomarkers of inflammation. Therefore, it is of great significance to develop an efficient single chemical sensor that can simultaneously detect these two biomarkers. To achieve the goal, we developed a dual-locked fluorescence probe (TPA-DNP) by fusing two targets activated reporting system, its implementation was achieved by turning-on the fluorescence of TPA-DNP through LDs and HClO/ClO- simultaneously. In simulated LDs environment, TPA-DNP displayed excellent selectivity to HClO/ClO-, high sensitivity (LOD = 0.527 μM) and strong anti-interference ability. In addition, cell and zebrafish imaging experiments showed that TPA-DNP could be utilized to visualize exogenous/endogenous HClO/ClO- in LDs environment, and could also be used to observe the impact of LDs changes on the HClO/ClO- detection. On the basis, TPA-DNP served as a favorable tool to achieve visualization of inflammatory dynamic changes.

A Molecularly Imprinted Fluorescence Sensor Based on Upconversion-Nanoparticle-Grafted Covalent Organic Frameworks for Specific Detection of Methimazole

Rapid detection and sensitive analysis of MMZ is of great importance for food safety. Herein, a fluorescent molecularly imprinted sensor based on upconversion nanoparticles (UCNPs) grafted onto covalent organic frameworks (COFs) was designed for the detection of MMZ. COFs with a high specific surface area and excellent affinity serve as substrates for grafting of UCNPs, which can inhibit the aggregation burst of UCNPs and improve the mass transfer rate of the sensor. Through a series of characterizations, it was found that the proposed UCNP-grafted COFs@MIP-based sensor had good optical stability, high adsorption efficiency, strong anti-interference ability, and high sensitivity owing to the integration of the advantages of UCNPs, COFs and MIPs. Under the optimal conditions, a good linear relationship was presented between the fluorescence intensity of UCNP-grafted COFs@MIPs and the methimazole concentration in the range of 0.05–3 mg L−1, and the detection limit was 3 μg L−1. The as-prepared UCNP-grafted COFs@MIPs were successfully applied for the detection of MMZ in actual samples, and the results were relevant with those determined by high-performance liquid chromatography. The sensor has good sensitivity, reusability, and high selectivity, which are highly valuable in the rapid analysis and detection of food safety.

Facile fluorescent sensor for rapid and selective detection of phytic acid in food based on phosphatase-like activity of Zr(IV)-Glu complex

Artificial enzymes have attracted much attention in food analysis because of their simple preparation, low cost, and strong stability. However, the most used artificial enzymes are based on oxidoreductases such as oxidase, peroxidase, catalase, and laccase. There are few reports on hydrolases like phosphatase for food analysis. Herein, a novel green zirconium-glutamic acid (Zr(IV)-Glu) complex was prepared using Zr ions and glutamic acid. The Zr(IV)-Glu complex was first found to possess excellent phosphatase-like activity, which was used to establish a fluorescent sensor for detecting phytic acid (PA). The Zr(IV)-Glu complex can catalyze the hydrolysis of 4-methylumbellione phosphate disodium salt (4-MUP) to produce blue fluorescent products with fluorescence emission peaks at 448 nm. PA with six phosphate groups can attach on the surface of Zr(IV)-Glu to form Zr-O-P bond and inhibit the catalytic activity of Zr(IV)-Glu, leading to the decrease of fluorescence in the system. The change of fluorescent intensity at 448 nm was positively correlated with the PA content, so that a fluorescent sensor using the phosphatase-like activity of Zr(IV)-Glu was proposed to detect PA. The established sensor has high sensitivity, low detection limit (LOD) of PA to 58 μg·L-1, strong anti-interference ability, and excellent selectivity. This work can provide a new method for PA detection in food and further expand the application of phosphatase mimics.

An Adaptive IMM Algorithm for a PD Radar with Improved Maneuvering Target Tracking Performance

A pulse-Doppler (PD) radar has the advantage of strong anti-interference ability, and it is often used as a solution for maneuvering target tracking. In the application of target monitoring and tracking in PD radars, the interacting multiple model algorithm (IMM) has become the main and preferred choice due to its flexibility and high accuracy. However, the probability transfer matrix in classical IMM algorithms generally depends on constant prior knowledge, and if a PD radar is tracking a strong maneuvering target, it is inevitable to encounter some limitations, such as the possibility of target tracking trajectory deviation, and even a loss of the target. The Markov probability transfer matrix is proposed with an adaptive modification ability in real time to overcome the above problems in this paper. Additionally, for improving the speed of switching between the models, the fuzzy control system for secondary updating of model probability is adopted. By this means, the tracking accuracy of maneuvering targets is enhanced. Compared with the classical IMM algorithm, the corresponding simulation results for the PD radar indicate that the overall tracking accuracy of the proposed adaptive IMM algorithm is improved by 19.6%. In conclusion, the continuity and accuracy of the target trajectory can be effectively improved with the proposed adaptive IMM algorithm in PD radar cases.

Research Progress of High-Speed Data Transmission Technology for Lightweight and Small-Sized Unmanned Aerial Vehicle Platforms

With the continuous development of science and technology, UAV technology has been widely used in various fields. As an essential part, light and small UAV platforms have the advantages of being small, lightweight, and easy to operate and thus have been widely used in aerial photography, monitoring, rescue, and other fields. However, the traditional data transmission method can no longer meet the demand for the data transmission speed and stability of small and light UAV platforms. Wireless optical communication has the advantages of being high-speed and license-free, as well as having a large bandwidth strong anti-interference ability, and good confidentiality. Therefore, this paper aims to study high-speed data transmission technology for light and small UAV platforms to improve their transmission speed and stability. In this paper, the characteristics and advantages of UAV airborne laser communication are first elaborated to illustrate the advancements and importance of data transmission technology based on light and small UAV platforms. Then, the composition of a UAV airborne laser communication system is clarified to illustrate the feasibility of conducting airborne laser communication research. Then, the current domestic and international research status of people on light and small UAV airborne laser communication high-speed data transmission systems is reviewed, and its key technical features are analyzed. Finally, the prospects for its application and development trend are investigated.

An energy-based pulsar period estimation method using Hilbert curve and double CNNs

In order to accurately estimate the period of X-ray pulsars to improve navigation performance, this paper proposes a pulsar period estimation method based on photon energy using reverse Hilbert coding and double Convolutional Neural Networks (CNNs) discrimination. This method uses photon energy information to perform epoch folding. It converts one-dimensional contour information into two-dimensional image signals through reverse Hilbert curve and recognizes contour image features through CNN models to determine the optimal period. According to the simulation results, the period estimation accuracy of this method is 0.5350 ns, which is 65.71% higher than the χ2 epoch folding method. The contour phase accuracy is 0.0004767, which is 41.93% higher than the χ2 epoch folding method. At the same time, the observation time and noise interference that may affect the accuracy of period estimation are also quantitatively analyzed. In addition, in order to simulate real navigation scenarios, this paper also conducts dynamic period estimation experiments on PSR B0531+21 pulsar in a specific period of time. The method proposed in this paper has the advantages of high precision, fast calculation speed, strong anti-interference ability and accurate dynamic period estimation, which can significantly improve the navigation performance of X-ray pulsars.