High Linearity Research Articles

Optimization, Validation, and Application of Cleanup-Coupled Liquid Chromatography–Tandem Mass Spectrometry for the Simultaneous Analyses of 35 Mycotoxins and Their Derivatives in Cereals

Mycotoxins occur singly or as co-contaminants and are primarily present in carbohydrate-rich foods such as cereals and cereal-based products. To effectively monitor mycotoxin co-contamination in cereals and cereal-based products, the simultaneous analysis of mycotoxins and their derivatives is required. Therefore, we coupled cleanup with LC-MS/MS for the rapid and robust quantitation of 35 analytes in wheat samples, including ergot alkaloids (EAs), which are rarely included in such analyses. To investigate the effects of different mycotoxin types on adsorbents, various dispersive solid-phase extraction sorbents were evaluated; a C18 end-capped sorbent exhibited the most effective cleanup performance. The method was validated by analyzing samples fortified with the mycotoxins at three concentration levels. The results exhibited high linearity, high recoveries, and repeatability. The methodology was applied for commercial cereal samples. The cereal samples were found to be 74% contaminated, and two samples measured levels of EAs at 609.63 μg/kg and 294.93 μg/kg, exceeding the limits defined by the EU for rye milling products. These findings highlight the validity of our novel method and the necessity of continuously monitoring mycotoxin levels in cereals to ensure food safety.

Chromatographic analysis of ponatinib and its impurities: method development, validation, and identification of new degradation product

BackgroundPonatinib, a third-generation tyrosine kinase inhibitor, is employed in the management of adult chronic myeloid leukemia. Nevertheless, the presence of process impurities and degradation impurities linked to ponatinib may potentially influence its effectiveness and safety. Therefore, the objective of this research was to establish a robust liquid chromatography method and systematically validate it for the detection of substances related to ponatinib.MethodsThe separation of ponatinib and its impurities was conducted using an Agilent 5HC-C18 chromatographic column (4.6 mm × 250 mm, 5 μm). The mobile phase A comprised a mixture of water and acetonitrile in a 9:1 ratio, with an aqueous solution of pH 2.4 containing 2 mM potassium dihydrogen phosphate and 0.4% triethylamine. Mobile phase B, consisting of acetonitrile, was eluted in a gradient fashion. The flow rate was set at 1.0 mL/min, detection wavelength at 250 nm, column temperature at 40°C, and injection volume at 10 μL.ResultsThe method demonstrated high specificity, sensitivity, solution stability, linearity, precision, accuracy, and robustness. Additionally, this research unveiled a novel compound, imp-B, generated via the oxidative degradation of ponatinib. The molecular structure of the newly discovered product was elucidated through the utilization of nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS).ConclusionIn conclusion, the chromatographic method developed in this study has the potential to be utilized for the detection of ponatinib and its impurities, thereby offering significant insights for quality assessment in ponatinib research.

Reversible addition-fragmentation chain transfer enhanced aggregation signal-on fluorescence detection of alkaline phosphatase.

The instability of the signal intensity of fluorescent biosensors and the false signals have been significant factors affecting the performance of biosensors. Herein, a novel signaling system is devised through the application of reversible addition-fragmentation chain transfer (RAFT) polymerization with monomers containing the tetraphenylethylene (TPE) groups. TPE exhibits an aggregation-induced emission (AIE) phenomenon in certain solvents, mainly due to the blockage of the rotation of its four benzene rings, which also exist in the aggregated state. With this property, a series of molecules are modified based on click chemistry for RAFT polymerization using Fe3O4 magnetic beads as the carriers, and stable aggregated luminescent TPE polymers are formed on the surface of magnetic beads to realize the transformation of fluorescence signal from "0" to "1". In addition, the fluorescence signal demonstrates a positive correlation with alkaline phosphatase (ALP) activity, which can be quantified by measuring the fluorescence intensity. The biosensor exhibits high sensitivity and good linearity in the range of 0.1-5 U/L, with a LOD of 0.079 U/L. Furthermore, the designed strategy demonstrated satisfactory performance in the quantitative determination of ALP activity in serum samples, indicating that the signaling system developed by combining RAFT polymerization and AIE molecules has an important application in the field of fluorescent biosensors.

Eccentric Core Photonic Crystal Fiber Magnetic Field Sensor Based on Surface Plasmon Resonance with Extremely High Linearity

Eccentric Core Photonic Crystal Fiber Magnetic Field Sensor Based on Surface Plasmon Resonance with Extremely High Linearity

Varying Performance of Low-Cost Sensors During Seasonal Smog Events in Moravian-Silesian Region

Air pollution monitoring in industrial regions like Moravia-Silesia faces challenges due to complex environmental conditions. Low-cost sensors offer a promising, cost-effective alternative for supplementing data from regulatory-grade air quality monitoring stations. This study evaluates the accuracy and reliability of a prototype node containing low-cost sensors for carbon monoxide (CO) and particulate matter (PM), specifically tailored for the local conditions of the Moravian-Silesian Region during winter and spring periods. An analysis of the reference data observed during the winter evaluation period showed a strong positive correlation between PM, CO, and NO2 concentrations, attributable to common pollution sources under low ambient temperature conditions and increased local heating activity. The Sensirion SPS30 sensor exhibited high linearity during the winter period but showed a systematic positive bias in PM10 readings during Polish smog episodes, likely due to fine particles from domestic heating. Conversely, during Saharan dust storm episodes, the sensor showed a negative bias, underestimating PM10 levels due to the prevalence of coarse particles. Calibration adjustments, based on the PM1/PM10 ratio derived from Alphasense OPC-N3 data, were initially explored to reduce these biases. For the first time, this study quantifies the influence of particle size distribution on the SPS30 sensor’s response during smog episodes of varying origin, under the given local and seasonal conditions. In addition to sensor evaluation, we analyzed the potential use of data from the Copernicus Atmospheric Monitoring Service (CAMS) as an alternative to increasing sensor complexity. Our findings suggest that, with appropriate calibration, selected low-cost sensors can provide reliable data for monitoring air pollution episodes in the Moravian-Silesian Region and may also be used for future adjustments of CAMS model predictions.

Multifunctional CeO2:Fe3+ electrodes: Superior uric acid sensing and high-efficiency supercapacitor application

This study investigates the versatile capabilities of iron-doped CeO2-modified carbon paste electrodes (FCO MCPE) for both enhanced uric acid (UA) detection and efficient energy storage applications. Iron-doped CeO2 nanoparticles were synthesized via combustion synthesis. Cyclic voltammetry (CV) showed a 29 % increase in anodic peak current (2.05 µA) with the FCO MCPE compared to bare carbon paste electrodes (BCPE) (1.59 µA), indicating improved catalytic properties. Analysis of scan rates revealed a diffusion-controlled oxidation process. Differential pulse voltammetry (DPV) demonstrated excellent linearity (R2 = 0.999) and low detection limits (LOD: 0.132 µM, LOQ: 0.442 µM). Selectivity tests confirmed the superior ability of the FCO MCPE to differentiate UA from dopamine (DA), with a high linearity (R2 = 0.998). Stability tests showed only an 11 % decrease in performance after 15 cycles. In super capacitor evaluations, FCO materials exhibited a high specific capacitance of 200.43 F g−1 at 2 mV/s and impressive cycling stability with 87.5 % capacitance retention after 5000 cycles. Electrochemical impedance spectroscopy (EIS) revealed efficient charge transfer with a peak specific capacitance of 52.39 F g−1 at 0.01 Hz. These findings underscore the potential of FCO MCPEs for both effective UA detection and efficient super capacitor applications.

Investigation of Electrochemical Fingerprints for Buzhong Yiqi Tang Extract Granules Using Diamond-Graphene Composite Electrode

This study presents a novel electrochemical fingerprinting method for Buzhong Yiqi Tang extract granules using a diamond-graphene composite electrode. The electrode was fabricated through chemical vapor deposition of graphene on high-pressure high-temperature synthetic diamond, resulting in a few-layer graphene coating as confirmed by Raman spectroscopy (I₂D/IG ratio ≈ 1.2) and XPS analysis (78% sp² C-C signal). Cyclic voltammetry revealed four anodic and three cathodic peaks, while differential pulse voltammetry provided enhanced resolution with eight distinct oxidation peaks. The method demonstrated high sensitivity (LODs 0.08-0.15mg/mL) and good linearity (R² > 0.995) over a concentration range of 0.5-10mg/mL. Comparison of fingerprints from individual herb extracts (Astragalus membranaceus, Panax ginseng, and Glycyrrhiza uralensis) elucidated the origins of major peaks in the Buzhong Yiqi Tang profile. Principal component analysis of fingerprints successfully differentiated between samples from three manufacturers, accounting for 87.3% of total variance. Strong correlations (r > 0.92) were observed between key DPV peak intensities and HPLC-determined concentrations of traditional chemical markers. The rapid analysis time, minimal sample preparation, and holistic representation of multiple electroactive components make this approach a promising complement to existing chromatographic methods for quality assessment of traditional Chinese medicine formulations.

Optimization Analysis of Low-Noise Amplifier

This paper mainly analyzes the important component of a wireless receiver – low-noise amplifiers (LNA). Low-noise amplifiers can reduce the effect of noise on the received signal and amplify signals. For the better development of wireless communication technology, remote control, and other related fields, it is necessary to optimize the design of low-noise amplifiers, so that low-noise operational amplifiers can finally obtain high gain, low noise figure, and other advantages. This paper analyzes the optimization design of LNA in the field of Global Navigation Satellite Systems (GNSS). This paper analyzes a low-noise amplifier design with the operation of concurrent dual-band for GNSS receivers with a single channel. The optimized design of a low-noise amplifier in this field uses a low-cost 0.18µm CMOS tube and adds load capacitances and a feedforward path to reduce the noise figure (NF) of the system. Noise figures in 1.2 GHz and 1.57 GHz bands are reduced by about 0.9 dB. In addition, the high gain, high linearity, and other excellent properties are shown in 1.2 GHz and 1.57GHz. In the application of 5G/6G network technology, the optimized design of Gallium Arsenide (GaAs) PHEMT technology with a gate length of 0.3µmm and inductively degraded common source topology phase structure is adopted. From this optimization, the noise figure is optimized to 1.3-1.4, and the gain of the system is 20-22 dB. At the same time, good linearity is also shown. Then, the prospects of semiconductor materials such as Gallium Nitride (GaN) and Indium Phosphide (InP), which have the advantages of high electron mobility and low-cost design, in optimizing low noise operational amplifiers. To a certain extent, the in-depth study of the optimal design of LNA can improve the technical level of wireless communication, aerospace, and other fields.

Comparative Analysis of Pharmaceutical Persistence in Canadian Wastewater Treatment Plants Utilizing Molecularly Imprinted Polymers and Commercial Solid Phase Extraction Sorbents

In this study, the performances of a synthesized Molecularly Imprinted Polymer (MIP) and a commercial Solid Phase Extraction (SPE) cartridge were compared in terms of the removal efficiency and quantification of pharmaceutical compounds in wastewater samples. Concentration analysis of Emtricitabine, Tenofovir, Naproxen, Diclofenac, Ibuprofen, and Efavirenz was conducted in influent, primary effluent, secondary effluent, and post-chlorination water samples using liquid chromatography-UV detection. Regressions analysis revealed high linearity (R2 values from 0.9980 to 0.9999) for the compounds, alongside recoveries ranging from 90.9% to 100%. The method detection limits (MDLs) were also determined. Removal efficiencies were computed, with Naproxen and Ibuprofen demonstrating complete removal (100%), while other compounds displayed different of removal efficiency levels. The MIP was found to perform slightly better than traditional SPE cartridges in terms of selectivity, efficiency, and overall performance. This study provides valuable insights into the concentrations of target compounds at various treatment stages, emphasizing the importance of choosing extraction cartridges in wastewater treatment processes.

Miniaturized Electrochemical Gas Sensor with a Functional Nanocomposite and Thin Ionic Liquid Interface for Highly Sensitive and Rapid Detection of Hydrogen.

Hydrogen has been widely used in industrial and commercial applications as a carbon-free, efficient energy source. Due to the high flammability and explosion risk of hydrogen-air mixtures, it is vital to develop sensors featuring fast-responding and high sensitivity for hydrogen leakage detection. This paper presents a miniaturized electrochemical gas sensor by elaborately establishing a nanocomposite and thin ionic liquid interface for highly sensitive and rapid electrochemical detection of hydrogen, in which a remarkable response time and recovery time of approximately 6 s was achieved at room temperature. A screen-printed carbon electrode was modified with a reduced graphene oxide-carbon nanotube (rGO-CNT) hybrid and platinum-palladium (Pt-Pd) bimetallic nanoparticles to realize high sensitivity. To achieve miniaturization and high stability of the sensor, a thin-film room-temperature ionic liquid (RTIL) was employed as the electrolyte with a significantly decreased response time. The fast-responding hydrogen sensor demonstrates excellent performance with high sensitivity, linearity, and repeatability at concentrations below the lower explosive limit of 4 vol %. The engineered high-performance interface and gas sensor provide a promising and effective strategy for gas sensor design and rapid hazardous gas monitoring.

Photoinduced Zn-Air Battery-Assisted Self-Powered Sensor Utilizing Cobalt and Sulfur Co-Doped Carbon Nitride for Portable Detection Device.

Most self-powered electrochemical sensors (SPESs) are limited by low open circuit voltage and power density, leading to a narrow detection range and low sensitivity. Herein, a photoinduced Zn-air battery-assisted SPES (ZAB-SPES) is proposed based on cobalt and sulfur co-doped carbon nitride with the cyano group (Co, S-CN). The cyano functionalization remarkably enhances visible light utilization, and the cyano moiety acts as an electron-withdrawing group to promote electron enrichment. Co and S co-doping can create a p-n homojunction within carbon nitride, enabling the efficient migration and separation of carriers, thereby significantly improving the performance of the oxygen reduction reaction. The synergistic effects endow Co, S-CN photocathode with an open circuit voltage of 1.85V and the maximum power density of 43.5µW cm-2 in the photoinduced ZAB. Employing heavy metal copper ions as the target model, the photoinduced ZAB-SPES exhibited dual-mode and sensitive detection. Furthermore, a portable detection device based on the photoinduced ZAB-SPES is designed and exhibits high linearity in the range of 5 ~ 600nM with a detection limit of 1.7nM. This work offers a portable detection method based on the photoinduced ZAB-SPES in the aquatic environment.

Design method of transverse gradient coils based on nonuniform rational B-spline (NURBS) curves.

To propose a hybrid transverse gradient coil design method that leverages current density-based methods and nonuniform rational B-spline (NURBS) curves to optimize the performance and manufacturability of gradient coils. Our method begins by generating an initial wire configuration using a density-based method. Then, we fit NURBS curves to the configuration, and adjust the control parameters of these curves to meet performance requirements. To ensure adequate spacing and even distribution of wires, an objective function utilizing the sigmoid function to modulate the distances between adjacent wires is constructed. Critical factors including gradient efficacy, linearity, eddy current, and torque, are incorporated as constraints. The piecewise nature of the curves provides the flexibility to independently control specific segments without impacting others. We validated our method by designing three shielded transverse gradient coils: a whole-body coil, an ultra-short whole-body coil, and an ultra-short asymmetric head coil. The primary design objectives were to improve linearity and maintain gradient efficiency. All optimized coils demonstrated significant linearity across large diameters of spherical volumes (DSVs), while gradient efficiency, eddy currents, and torque were well-balanced. The objective function effectively managed the wire concentrations required for high linearity, ensuring even wire arrangement and adequate spacing. We leveraged the flexibility of the curves to individually tailor wire paths for specific objectives, such as preventing interference between coils and passive shimming and accommodating wire connections and cooling circuits. This method provides a versatile and effective approach for designing high-performance and manufacturable gradient coils.

Synergistic effects in Na0.5Bi0.5TiO3-based thin film through stress field regulation for excellent capacitive energy storage

Thin film dielectric capacitors have attracted significant attention under the current trend of integration and portability in electronic devices. In this work, Na0.5Bi0.5(Fe0.03Ti0.97)O3–SrTiO3 (NBFT–STO) thin films are synthesized via sol–gel method onto flexible Pt/Mica and rigid Pt/Ti/SiO2/Si substrates, respectively to obtain NBFT–STO dielectric capacitors under different local stress fields. Synergistic effects between dielectric polarization and breakdown strength (EBD), as well as dielectric polarization and polarization hysteresis are obtained, with the rigid one exhibiting higher EBD and the flexible one possessing high polarization linearity. Excellent capacitive energy storage performance with Wrec of 28.00 J/cm3 and η of 70.44 % are obtained at 20 kHz for the NBFT–STO thin film onto Pt/Mica. These findings provide a new route to modulate polarization behavior of NBT–based thin film through stress field regulation for capacitive energy storage.

Ferrimagnet-Based Neuromorphic Device Mimicking the Ventral Visual Pathway for High-Accuracy Target Recognition.

The ventral visual pathway (VVP) of the human brain efficiently implements target recognition by employing a deep hierarchical structure to build complex visual concepts from simple features. Artificial neural networks (ANNs) based on spintronic devices are capable of target recognition, but their poor interpretability and limited network depth hinder ANNs from mimicking the VVP. Hardware implementation of the VVP requires a biorealistic spintronic device as well as the corresponding interpretable and deep network structure, which have not been reported so far. Here, we report a ferrimagnetic neuron with a continuously differentiable exponential linear unit (CeLu) activation function, which is closer to biological neurons and could mitigate the issue of limited network depth. Meanwhile, we also demonstrate that a ferrimagnet can construct artificial synapses with high linearity and symmetry to meet the requirements of weight update algorithms. Based on these neurons and synapses, we propose an all-spin convolutional neural network (CNN) with a high interpretability and deep neural network, to mimic the VVP. Compared to the state-of-the-art spintronic-based neuromorphic computing model, the CNN with bionic function, using experimentally derived device parameters, achieves high recognition accuracies of over 91% and 98% on the CIFAR-10 datasets and the MNIST datasets, respectively, showing improvements of 1.13% and 1.76%. Our work provides a promising method to improve the bionic performance of spintronic device-based neural networks.

Degradable Multilayer Fabric Sensor with Wide Detection Range and High Linearity.

Integration of multiple superior features into a single flexible pressure sensor would result in devices with greater versatility and utility. To apply the device to a variety of scenarios and solve the problem of accumulation of e-waste in the environment, it is highly desirable to combine degradability and wide-range linearity characteristics in a single device. Herein, we reported a degradable multilayer fabric (DMF) consisting of an ellipsoidal carbon nanotube (ECNT) and polyvinylpyrrolidone/cellulose acetate electrospun fibers (PEF). The alternative layer-by-layer stacking of the ECNT and PEF notably accelerates the sensitivity toward pressure. The optimized device demonstrated a sensitivity of 3.38 kPa-1 over a wide measurement range from 0.1 to 500 kPa, as well as great mechanical stability over 2000 cycles. A good degradation performance was confirmed by both Fourier transform infrared (FTIR) characterization and decomposition experiments in sodium hydroxide solution. The fabricated sensor is capable of precepting a variety of physiological scenarios including subtle arterial pulse, dancing training, walking postures, and accidental falls. This work throws light onto the fundamental understanding of the mechanical interfacial coupling in piezoresistive materials and provides possibilities for the design and development of on-demand wearable electronics.

Parameter Optimization of Semiconductor Gas Sensor under AC Impedance Measurement.

Semiconductor gas sensors were confirmed to perform high linearity and a stable baseline under alternating current (AC) impedance measurements. However, a procedure to determine the optimal parameters of AC impedance measurements is still lacking. Taking the detection of SF6 decomposition gas as an example, this work has established a model of semiconductor gas sensors under AC impedance measurement. Employing four types of sensors to detect three gases (H2S, SO2, and CO), the effectiveness of the optimization method has been validated, as well. With the high linearity and stable baseline obtained from AC impedance measurement, it enables rapid correction of temperature drift within environmental temperatures ranging from 10 to 30 °C. Overall, the proposed method can provide a novel approach to inhibit the drift failure of semiconductor gas sensors.

Self‐Powered Iontronic Capacitive Sensing Unit with High Sensitivity in Charge‐Output Mode

AbstractThe operation of iontronic capacitive sensors typically requires an external alternating current (AC) power source, resulting in additional energy consumption and AC‐frequency‐related sensing performance. Here, a class of self‐powered iontronic capacitive sensing units (SICSUs) is proposed based on a dynamic electric double layer (EDL), with a significant charge sensitivity of up to 24270 pC N−1, surpassing most piezoelectric materials by nearly 10 times. The effects of various design parameters and loading conditions on the sensing performance of the SICSUs are systematically investigated. The EDL at the hydrogel‐electrode interface is characterized in situ, revealing the underlying mechanism for high sensitivity and linearity. The capability of SICSUs in detecting diverse human‐related mechanical loads is demonstrated. Furthermore, a robotic hand equipped with a SICSU‐based artificial algesia sensor is fabricated to mimic the withdrawal reflex behavior of a human hand when its skin detects noxious stimuli caused by sharp objects.

Design of an FBG-Based Tension Sensor With High Sensitivity and Linearity for Cable-Driven Continuum Robots

Design of an FBG-Based Tension Sensor With High Sensitivity and Linearity for Cable-Driven Continuum Robots

A 1.25-GS/s 14-bit pipelined ADC using a current-feedback flipped input buffer and large dither technique to achieve high linearity

A 1.25-GS/s 14-bit pipelined ADC using a current-feedback flipped input buffer and large dither technique to achieve high linearity

Monitoring of crack-induced electromagnetic vector field based on tunnel magnetoresistance effect

Electromagnetic radiation technology is widely used as a non-destructive, non-contact monitoring method, but the spatial information contained in it is ignored. A three-axis electromagnetic sensor was developed to monitor the electromagnetic radiation generated by the fracture of brittle rocks based on the tunnel magnetoresistance effect. The sensor has significant independence, anti-interference in three orthogonal directions, and exhibits high linearity. The monitored signals can be regarded as the components of the electromagnetic field vector in three directions. Based on the idea of vector synthesis, the peak index and peak matching index of the synthesized signal are extracted for the directional characterization and can be used to identify the direction of cracks.