Superior Linearity Research Articles

Optimal design parameter estimation and analytical investigation of MEMS quadruple touch mode capacitive pressure sensor

Purpose Touch mode capacitive pressure sensors (TMCPS) offer superior sensitivity and linearity in comparison to normal mode CPS and have therefore seen substantial improvements in modeling and construction. This study aims to develop a sensor that is highly robust, with near-linear output characteristics, increased sensitivity and superior overload protection, making it an ideal choice for deployment in harsh industrial environments. Design/methodology/approach The proposed sensor design uses a substrate with a multi-step notch, introducing a new quadruple TMCPS and uses a small deflection model for mathematical analysis. Addition of a multi-step notch to traditional touch mode capacitive sensors results in quadruple touch regions which further enhances its operational range performance. Findings The simulation of diaphragm deflection in response to pressure is carried out by using COMSOL Multiphysics, whereas MATLAB is used for analytical simulations pertaining to variations in capacitance and capacitive sensitivity. Comparing with earlier models, there is a noticeable enhancement in capacitance, experiencing a fivefold increase. The achieved value stands at 50.1 pF, reflecting improved sensitivity for applied pressure ranging from 0 to 2 MPa. Originality/value In existing literature to improve the performance of the single TMCPS, a double-sided TMCPS has been developed. To enhance sensor performance, a substrate with a multi-step notch is proposed. The notch creates four touch regions with varying gap depths, resulting in increased capacitance and capacitive sensitivity.

A Low-Computational-Complexity Digital Predistortion Model for Wideband Power Amplifier.

This paper proposes a Composition Piecewise Memory Polynomial (CPMP) digital predistortion model based on a Vector Switched (VS) behavioral model to address the challenges of severe nonlinearity and strong memory effects in wideband power amplifiers (PAs). To tackle this issue, two thresholds are calculated and used to segment the envelope values of the input signal according to the nonlinear distortion characteristics of the PA. In this approach, a Generalized Memory Polynomial (GMP) model is employed for the lower segment, a Memory Polynomial (MP) model is employed for the middle segment, and a higher-order GMP model is employed for the upper segment. By sharing the fundamental MP among the proposed segmented models and leveraging a design methodology that configures different cross terms, memory depths, and polynomial orders for each segment, this model achieves superior linearization performance while simultaneously reducing the computational complexity associated with model extraction. The experimental results demonstrate that the adjacent channel power ratio (ACPR) of the predistorted PA output signal using the proposed model improves from -36 dBc to -54 dBc, matching the performance of the GMP model. Furthermore, this performance is 0.5 dBc better than the Piecewise Dynamic Deviation Reduction (PDDR) and Decomposed Vector Rotation (DVR) models. Notably, the complexity of the proposed parameter extraction process is 28.8% of the DVR model, 21.79% of the GMP model, and 12.83% of the PDDR model.

Enhanced Room-Temperature NO2 Sensing through Deep Functional Group Hybridization in Nitrogen-Doped Monolayer Ti3C2Tx.

Nitrogen dioxide (NO2) is a significant environmental and human health hazard. Current NO2 sensors often lack sensitivity and selectivity under ambient conditions. This study investigates ammonia pyrolysis modification of monolayer Ti3C2Tx MXene to enhance NO2 detection at room temperature. Nitrogen-doped Ti3C2Tx demonstrates a substantial improvement in sensitivity, with a response of 8.87% to 50 ppm of NO2 compared to 0.65% for the original sensor, representing a 13.8-fold increase. The nitrogen-doped sensor also exhibits superior selectivity and linearity for NO2 under ambient conditions. Theoretical analysis shows that nitrogen incorporation promotes enhanced interaction between Ti3C2Tx and its surface oxygen-containing functional groups through electronic hybridization, resulting in improved adsorption energy (1.80 |eV|) and electron transfer efficiency (0.67 |e|) for NO2, thereby enhancing its gas-sensing performance. This study highlights the potential of ammonia pyrolysis-treated Ti3C2Tx MXene for advancing NO2 sensor technologies with heightened performance at room temperature.

Quantitative evaluation of striatal uptake ratios using an adaptive template registration method for 123I-ioflupane dopamine transporter SPECT.

123I-FP-CIT (123I-Ioflupane) SPECT shows strong accumulation in the striatum, but morphological standardization is challenging due to low accumulation outside the striatum, particularly in subjects with marked striatal decline. In this study, morphological standardization without MRI was achieved using the adaptive template registration (ATR) method to create a subject-specific optimized template with weighted images of normal-type and egg-shape-type templates. The accuracy of a quantitative method for calculating the ratio with nonspecific accumulation in the occipital lobe was evaluated by placing voxels-of-interest (VOI) on standardized images, particularly targeting the striatum. The average images of eight subjects, demonstrating normal-type and egg-shape-type tracer accumulation in 123I-Ioflupane SPECT, were utilized as normal and disease templates, respectively. The study included 300 subjects that underwent both 123I-Ioflupane SPECT and MRI for the diagnosis of suspected Parkinson's disease or for exclusion diagnosis. Morphological standardization of SPECT images using structural MRI (MRI-based method) was considered the standard of truth (SOT). Three morphological standardizations without MRI were conducted. The first involved conventional morphological standardization using a normal template (fixed template method), the second employed the ATR method, with a weighted template, and the third used the split-ATR method, processing the left and right striatum separately to address asymmetrical accumulation. VOIs were set on the striatum, caudate, putamen as regions of specific accumulation, and on the occipital lobe as a reference region for nonspecific accumulation. Results showed significant and robust linearity in the striatal accumulation ratios for all templates when compared with the occipital lobe accumulation ratio when using the MRI-based method. Comparing intra-class correlations for different linearities, the ATR method and split-ATR method demonstrated higher linearity in the striatum, caudate, and putamen. The split-ATR method showed similar improvements, although more linearity than some of the ATR methods; the effectiveness of the Split-ATR method may vary by image quality, and further validation of its effectiveness in diverse asymmetric accumulation cases seemed warranted. The use of optimized templates, such as the ATR and split-ATR methods, improved reproducibility in fully automated processing and demonstrated superior linearity compared to that of MRI-based method, in the ratio to the occipital lobe. The ATR method, which enables morphological standardization when using SPECT images only, proved highly reproducible for clinical quantitative analysis of striatal accumulation, facilitating its clinical use.

Sensitive strain sensors with wide-range detection and high stability for intelligent human motion monitoring

Miniaturized wearable electronic devices with strain sensors as core sensing elements hold significant applications in health monitoring and human-machine interaction. However, it remains a challenge to develop strain sensors with optimal response linearity, a wide detection range, and stability. In this study, to satisfy the above requirements, we construct high-performance wearable strain sensors (rGO-CNTOH@PSE) by a strategy of hybridizing conductive fillers with stretchable substrates. In detail, a synergistic conductive network is developed by adopting OH-containing carbon nanotube (CNTOH) and reduced graphene oxide (rGO) fillers with an appropriate mass ratio. After the network is integrated into a porous silicone elastomer substrate formed by the salt templating method, the developed strain sensor exhibits distinct resolution, consistent repeatability, and superior response linearity across a wide strain detection range of 0.3–303.03 %. Furthermore, the sensor also maintains good response stability over 15000 cycles of strain. We also demonstrate that this strain sensor showing outstanding exceptional detection performance has the capability for full-range human motion detection. A wireless smart electronic glove is developed based on the sensor, which can accurately recognize gesture movements and control a bionic robotic hand to replicate human hand actions, offering the potential for replacing manual tasks (such as, grasping in hazardous environments) in the future.

HyperGen: Compact and Efficient Genome Sketching using Hyperdimensional Vectors.

Genomic distance estimation is a critical workload since exact computation for whole-genome similarity metrics such as Average Nucleotide Identity (ANI) incurs prohibitive runtime overhead. Genome sketching is a fast and memory-efficient solution to estimate ANI similarity by distilling representative k-mers from the original sequences. In this work, we present HyperGen that improves accuracy, runtime performance, and memory efficiency for large-scale ANI estimation. Unlike existing genome sketching algorithms that convert large genome files into discrete k-mer hashes, HyperGen leverages the emerging hyperdimensional computing (HDC) to encode genomes into quasi-orthogonal vectors (Hypervector, HV) in high-dimensional space. HV is compact and can preserve more information, allowing for accurate ANI estimation while reducing required sketch sizes. In particular, the HV sketch representation in HyperGen allows efficient ANI estimation using vector multiplication, which naturally benefits from highly optimized general matrix multiply (GEMM) routines. As a result, HyperGen enables the efficient sketching and ANI estimation for massive genome collections. We evaluate HyperGen 's sketching and database search performance using several genome datasets at various scales. HyperGen is able to achieve comparable or superior ANI estimation error and linearity compared to other sketch-based counterparts. The measurement results show that HyperGen is one of the fastest tools for both genome sketching and database search. Meanwhile, HyperGen produces memory-efficient sketch files while ensuring high ANI estimation accuracy. A Rust implementation of HyperGen is freely available under the MIT license as an open-source software project at https://github.com/wh-xu/Hyper-Gen. The scripts to reproduce the experimental results can be accessed at https://github.com/wh-xu/experiment-hyper-gen.

Fiber optic Fabry–Pérot salinity sensor based multiple conductive hydrogel sensing layers

This study introduces a new type of salinity sensor based on fiber optic Fabry-Pérot (FOFPS) featuring a tip coated with intelligent chemical cross-linked network materials. The sensor integrates a single-mode optical fiber, capillary tube, and quartz rod, bonding both ends using UV glue. Furthermore, it employs a multi-layer coating of polyacrylic acid (PAA)-polyacrylamide (PAAm) hydrogel achieved through layer-by-layer stacking technology. Results indicate the FOFPS's capability to measure salinity in aqueous. Across concentrations ranging from 0 ‰ to 45 ‰, a linear correlation between wavelength and concentration is observed. FOFPS utilizing PAA-PAAm hydrogel exhibits a sensitivity of approximately 1.241 nm/‰, high linearity of 0.995, and maximum drift of 57.971 nm. These findings underscore the efficacy of PAA-PAAm hydrogel as a sensing layer in FOFPS, highlighting its superior adjustability, responsiveness, linearity, and suitability for environmental refractive index sensing applications.

Inverse fitting direct absorption spectroscopy Technology: Simplified implementation and enhanced performance

The conventional direct absorption spectroscopy (DAS) technique has been plagued by the difficulty of obtaining accurate baseline, which is caused by photoelectric drift and the absence of non-absorbing regions in the transmitted light intensity signal. An inverse fitting direct absorption spectroscopy (IF-DAS) technique has been proposed to address this difficulty. The technique leverages the intrinsic nonlinear intensity response of tunable lasers to achieve baseline-free concentration measurements. It offers the advantages of being straightforward to implement, baseline-free, calibration-free, and resistant to photoelectric signal drift. Its efficacy was validated using an example under ambient temperature and atmospheric pressure conditions. The performance of the IF-DAS technique was compared with that of the conventional DAS technique through standard experimental tests. The results demonstrate that the IF-DAS technique is less susceptible to fluctuations in light intensity, exhibits superior linearity and accuracy, with an R2 value of 0.99986 and an overall error of less than 2%. This technique shows potential for application in harsh scenarios such as reactive flow fields and long-term engineering applications.

RF linearity and improved transconductance of ScAlN/GaN HEMT with novel inverse L-shaped gate structure

In this study, we investigate the enhancement of effective transconductance and gain linearity in submicrometer gate AlGaN-barrier-based transistors utilizing ScAlN/GaN coupling-channel structures. A novel asymmetric gate design, incorporating an AlGaN cap on ScAlN/GaN HEMT, is proposed. This configuration demonstrates a flat transconductance profile and significantly reduced transconductance derivative, thereby improving the linearity of GaN-based transistors. For transistors with a gate length of 0.5 μm, both the current gain cut-off frequency and power gain cut-off frequency are measured at 53.52 GHz and 72.98 GHz, respectively. These values represent a more than threefold increase from the corresponding frequencies of conventional devices. Moreover, the theoretical Output Third-Order Intercept value of the proposed structure has increased by 7.5 dBm compared to conventional HEMTs. This superior linear performance can be attributed to the combined effect of AlGaN cap layer and air cavity. Furthermore, the introduction of the ScAlN layer results in a substantial impact, including a decrease in electron concentration from 4.96 × 1019/cm3 to 1.98 × 1019/cm3 and an increase in electron velocity from 4.5 × 107 to 7.6 × 108 cm/s. These findings underscore the potential of the proposed device for high-frequency applications requiring superior linearity.

High pH stability and detection of α-synuclein using an EGFET biosensor with an HfO2 gate deposited by high-power pulsed magnetron sputtering

In this research, hafnium oxide (HfO2) was first fabricated in an in-house-developed high-power pulsed magnetron sputtering system (HiPIMS) functionalized for application as a high-performance extended gate field-effect transistor (EGFET) for the detection of pH and proteins associated with Parkinson's disease (PD). PD is the second most common neurodegenerative disease in elderly people after Alzheimer's disease. The α-synuclein protein in patients’ blood may be a potential biomarker in the early stage of PD. Detection of α-synuclein with high sensitivity and nonspecific binding through HfO2-EGFET biosensors has the advantages of low cost and simple fabrication from disposable EGs. Among the duty cycle conditions tested, HfO2 deposited at a 25% duty cycle in HiPIMS exhibited superior pH sensitivity and linearity, with values of 56.4 mV/pH and 99.7%, respectively. The hysteresis width and drift coefficient are −3 mV and 0.3 mV/h, respectively. To overcome the Debye length limitation, 100-fold diluted phosphate buffer solution and the PMOS configuration were used to determine the α-synuclein for which the isoelectric point was 4.67. The negative gate bias in the PMOS configuration successfully causes α-synuclein to approach the surface of HfO2 EG to achieve a sensitivity of 12.1 mV/dec and a linearity of 99.5% in the range of 0.1–1000 pg/mL. The limit of detection is 0.198 pg/mL, and the immobilized surface ultimately binds specifically, resulting in low interference signals from other related biomarkers. This promising study shows that detecting various proteins involved in different diseases and performing clinical tests can be accomplished in the future.

Thermoelastic wave generation and its longitudinal wave propagation measurement by a microscopic optical interferometer

Laser ultrasonics is a noncontact measurement method that uses a laser-induced elastic wave source in combination with an optical surface displacement-tracking system. This study compared the performances of two optical interferometers with different characteristics when applied to measurement of pulsed thermoelastic waves. The surface displacement-tracking system was designed to measure the center of the microscopic view. A pulsed laser beam irradiated a black ink layer to generate the thermoelastic waves. The out-of-plane displacement on the axially opposite side was then measured using either a Michelson interferometer or a Sagnac interferometer. The objective lens of the system was of a type commonly used in biological observations. The Michelson interferometer estimated a maximum displacement of 0.43 nm and a maximum sound pressure of 24.7 kPa. The signal-to-noise ratios from 16 averages were 14.9 dB (Michelson interferometer) and 19.2 dB (Sagnac interferometer). Furthermore, this paper compares the performance of the numerically estimated Sagnac interferometer outputs calculated from the measured Michelson interferometer outputs with the experimentally obtained Sagnac interferometer outputs. The numerically estimated Sagnac interferometer’s output was shown to be identical to the experimentally acquired output. The Michelson interferometer requires a higher average operating frequency (i.e., it needs a longer data acquisition time), although this interferometer does offer superior displacement output linearity. This property enables calculation of the sound pressure from the displacement amplitude. These findings indicated that combination of the measurement points of the Sagnac interferometer with those of the sparsely distributed Michelson interferometer reduced the measurement time when compared with a single use of the Michelson interferometer while also maintaining the data acquisition quality.

Small-strain folding of semi-rigid elastomer derives high-performance 3D-printable soft origami actuators

Elastomers with hyperelastic deformation bring prosperity to soft robotics, especially in constituting fluidic actuators, largely due to the merit of large deformation and airtightness. However, the large (typically 0.5–1.5 strain) in-plane stretching of such materials concurrent to motion generation inevitably causes energy loss, hinders force output and accuracy. Particularly, the high nonlinearity of the low-durometer (typically 10A to 30A Shore) hyperelastic elastomers makes the modeling and control of actuators a well-known challenge. In this work, we proposed an alternative approach of using semi-rigid elastomer of significantly larger durometer (70 A–100 A) to create the typical fluidic soft actuator with axial translation, by utilizing small-strain folding to generate motion. Deformation constraints and property programming are combined into a single-piece body, enabling easy fabrication by Selective Laser Sintering 3D-printing and post-treatment for origami patterned structure. Systematic analyses on the principles, modeling and design are presented. The long lifespan (over 1 million cycles), superior output linearity, high energy efficiency (more than 60% increase), and drastically improved force output (more than 98% increase) were validated experimentally, showing high potentials in enabling high-performance soft actuators that are easy to design, fabricate and drive, strong to use, and accurate to control, towards even wider applications.

A Dynamic Range Preservation Readout Integrated Circuit for Multi-Gas Sensor Array Applications

This study introduces a readout integrated circuit (ROIC) tailored for multi-gas sensor arrays featuring a proposed baseline calibration scheme aimed at mitigating the issue of sensor baseline variation. Unlike previous approaches, the proposed scheme stores each sensor’s baseline value and dynamically updates the signal extraction range accordingly during ROIC operation. This adjustment allows for the optimal use of the ROIC’s dynamic range, enhancing sensor uniformity and accuracy without the need for complex additional circuitry or advanced post-processing algorithms. We fabricated a prototype ROIC using a 180 nm CMOS process, achieving a low power consumption of 0.43 mW and a conversion rate of 50 kSPS. The prototype boasts an integrated noise level of 9.9 μVRMS across a frequency range of 0.1 Hz to 5 kHz and a dynamic range of 142.6 dB, coupled with superior linearity, indicated by a maximum integral non-linearity (INL) of −75.71 dB. This design significantly reduces sensor offset scattering to within 1 LSB of the A/D reference scale. In this study, the efficacy of the proposed scheme was validated using Figaro TGS-2600. The ROIC targets a sensitivity range from 0.54 to 0.23 for gas concentrations ranging from 5 ppm to 20 ppm and a resolution of 39 Ω for sensor resistance range from 10 kΩ to 90 kΩ. The enhancements in performance make the proposed ROIC a promising solution for precise gas concentration detection in sensor applications.

Ultrasonic synthesis of magnetic covalent organic frameworks and application magnetic solid phase extraction for rapid adsorption of trace bisphenols in food samples

A simple ultrasonic synthesis strategy was developed for a novel magnetic covalent organic framework. Firstly, the Fe3O4 nanoparticles were encapsulated by imine-type COF, which generated by the Schiff reaction of 4,4′,4′'-(1,3,5-Triazine-2,4,6-triyl)-trianiline (TAPT) and tris(4-formylphenyl)-amine (TFPA) using ultrasonic synthesis method within 2 h. The synthesised nanocomposites showed a sizeable specific surface area, and high adsorption capacity. A fast, sensitive MSPE method with Fe3O4@TAPT-TFPA-COF as adsorbent for analysing bisphenol compounds was developed. This method's advantages were simple operation, short extraction time, and avoidance of the use of centrifugal equipment. The method validation indicate that this method exhibited superior linearity, and detection limits range between 0.33 and 0.60 μg L–1. The recoveries of BPs ranged from 74.7 % to 107.0 %, with relative standard deviations of less than 3.8 % in water, milk, vinegar, and soy sauce samples. The proposed method was successfully applied for extracting BPs in food samples.

Aniline oligomer-assisted exfoliation of MoS2 nanosheets for high-performance room-temperature NO2 gas sensing

Two-dimensional transition sulfides (TMDs) are ideal materials for room-temperature gas sensing due to their high carrier mobility at room temperature. Nevertheless, the inferior response and incomplete recovery of TMDs at room temperature hinder their development in the field of the most advanced gas sensors. Herein, we propose two-dimensional surface p-p heterojunctions constructed via organic conjugated molecules assisted stripping of molybdenum disulfide (MoS2) for high-performance room-temperature nitrogen dioxide (NO2) gas sensing. The aniline tetramer (TANI) was employed as an exfoliation-assistant reagent, adhering evenly to the surface of the exfoliated MoS2 nanosheets, and forming a good MoS2/TANI heterostructure. The sensor built with this heterostructure has a 28.5% response to 1 ppm NO2 at room temperature, outperforming a standalone MoS2 sensor by more than fourfold. The device still has a significant response even at NO2 concentrations as low as 30 ppb. Furthermore, the MoS2/TANI-3 heterostructure gas sensor also exhibits excellent repeatability, long-term stability, superior linearity, and good selectivity at room temperature. Above all, the proposed design technique, as well as the developed structures, can pave the way for the development of high-performance TMDs-based gas sensors.

Structural and dimensional engineering of three-dimensional carbon nanotube/polydimethylsiloxane composite for stretchable sensor

A highly sensitive strain sensor is essential for the wearable electronic in constantly emerging applications such as human motion monitoring, personalized healthcare, human-machine interaction, soft robot and smart skin. However, most of the physical sensors currently reported are facing with challenges of non-adjustable sensing performance, unsatisfactory linearity, complicated preparation processes, and small working ranges, which greatly restricts their practical applicability. In this work, we proposal a facile technology base on the structural and dimensional engineering of carbon nanotube (CNT) conducting networks, to fabricate the flexible and stretchable strain sensor with tunable sensitivity and superior linearity in a wide sensing range. The three-dimensional CNT frameworks with adjustable density were constructed by the chemical vapor deposition method, which were used as the filler network to prepare the flexible CNT/polydimethylsiloxane (CNT/PDMS) composites. The resultant strain sensors base on the CNT/PDMS composites can realize the tunable sensitivities (gauge factor ranges from 0.7 to 233 at 100 % strain) by simply changing and regulating the structural density and macro-size of sensing strips. Meanwhile, the obtained sensors possess excellent linearity (R2 > 90 %) and repeatability on the 10 000 cycles. The technology developed in this work will offer a wide range of practical applications in wearable electronics field.

A Transient-Enhanced Autonomous Current Adaptation Buffer Amplifier

This paper proposes a transient enhanced autonomous current adaptation buffer amplifier (ACABA) that effectively resolves the slew rate degradation problem observed in the previous design. The proposed circuit enhances the transient responses, achieving faster step responses, superior linearity, and higher power efficiency. The cause of the degradation in the previous work has been elucidated, and a transient enhancement circuit is proposed to circumvent the slewing bottleneck. A prototype chip has been designed and fabricated in a 0.35μm CMOS process. From measurements, the proposed circuit improves settling time by 62.1%, enhances slew rate by 3.1 times, and reduces total harmonic distortion (THD) by 17 dB without extra static power consumption. With a 2.5V supply voltage, the proposed buffer amplifier allows a maximum input signal amplitude of 2.3 V with the THD below -60dB. Furthermore, the enhanced buffer amplifier exhibits the best power efficiency in both small-signal and large-signal performance compared to other state-of-the-art designs.

B-290 Development of a LCMS/MS Method for the Quantitation of Infliximab in Serum

Abstract Background Quantitative bottom-up proteomics of biotherapeutics has been successfully introduced in the clinical laboratory for therapeutic drug monitoring in recent years. The general workflow includes multiple steps: sample extraction/purification, reduction, alkylation, enzymatic digestion, desalting, and LC-MS/MS analysis of signature peptides. In this study, we developed an infliximab drug assay with desired operational efficiencies needed in a clinical laboratory. Evaluations included reduction/alkylation removal, trypsin digestion length, trypsin quality, online/offline/no sample desalting, multiple/single signature peptides, and whole protein/peptide internal standardization. Methods For sample preparation, a general procedure was initially followed. Briefly, protein precipitation with ammonium sulfate, re-suspension with buffer, reduction, alkylation, overnight enzymatic digestion, desalting, and LC-MS/MS analysis. To simplify the workflow, the steps of reduction and/or alkylation were omitted. The trypsin digestion time was varied from 2 h, 4 h, and overnight. TPCK-modified trypsin from two different vendors (Thermo Scientific and Millipore Sigma) were also compared for digestion efficiency. SILu™MAb infliximab stable-isotope labeled monoclonal antibody (Millipore sigma) was compared with customer synthesized stable-isotope labeled signature peptides as the internal standard. Different trapping cartridges were evaluated for online sample desalting and different analytical columns were evaluated for target peptide analysis. A Transcend TurboFlow TLX UHPLC System coupled to a TSQ Altis triple-quadrupole mass spectrometer was used (Thermo Scientific) operating in multiple reaction monitoring mode (2 transitions for each peptide and internal standard). Two signature peptides YASE (Sequence: YASESMSGIPSR) and GLEW (Sequence: GLEWVAEIR) from different chains of infliximab were analyzed. Results For sample preparation, the omission of protein reduction/alkylation from the workflow did not significantly affect YASE quantitation. The peak area of GLEW decreased by about 30% without reduction/alkylation. The evaluation of three calibration curves corresponding to the digestion time of 2, 4, and overnight respectively showed that 4 h was optimal for all the levels of calibrators if both signature peptides were used for quantitation. TPCK-modified trypsin from two different vendors were equal in digestion efficiency. The calibration curve using SILu™MAb infliximab stable-isotope labeled monoclonal showed superior linearity (R2 > 0.98) and recovery for each calibrator vs using stable-isotope labeled signature peptides as internal standard. With the optimized conditions, both signature peptides can be used for the accurate quantitation of infliximab. However, for monitoring both peptides simultaneously, the chromatography separation needed 14.5 min. On the contrary, 9 min is needed for monitoring a single peptide YASE. Conclusion In summary, systematic optimization of sample preparation and LC-MS/MS analysis was accomplished in this study. The entire workflow was simplified by removing the steps of reduction and alkylation and using optimal digestion time, which increases the efficiency and significantly facilitate the implementation of this assay.

Cone‐Shaped Electrodes for Capacitive Tactile Sensors with High Sensitivity and Broad Linearity Range

Flexible tactile sensors with high sensitivity typically suffer from a dramatically reduces pressure resolution with increasing pressure, resulting in narrow linear ranges and limited application scenarios. Herein, a capacitive tactile sensor based on cone‐shaped electrodes (CSE) that can maintain high sensitivity over a broad linearity range is proposed. The linear response comes from the novel sensing mechanism based on the change in the facing electrode area and the rational design of the conical architecture. Finite element analysis (FEA) confirms that the interfacial contact area between the elastic electrodes and the dielectric layer can respond linearly to pressure over a broad spectrum. Based on this strategy, the fabricated sensors perform a high sensitivity (0.23 kPa−1) and superior linearity (R2 = 0.999) across a wide pressure range of up to 130 kPa. The sensors demonstrate several key features, such as good repeatability, fast response speed, low detection limit, and high durability. These attributes enable the successful use of the sensors for monitoring artery pulses and providing weighting capabilities to robots, showing promising potential for applications in daily health monitoring and human‐machine interaction.

Use of Smartphone and Image Analysis in the Quantification of Vitamin C in Golden Berry (Physalis peruviana L.) Juice

Conventional methods used to quantify vitamin C require expensive equipment; however, the image analysis method has proven to be effective in quantifying various bioactive compounds and could be useful for small industries due to its low cost. In this sense, the objective was to evaluate the use of a Smartphone and image analysis in the quantification of vitamin C in golden berries juice. Calibration curves were elaborated with ascorbic acid standards (2.5-20 mg L-1) and the Folin-Ciocalteu chromophore reagent (10%). Fifteen color parameters (analytical responses) were obtained from images obtained with a Smartphone and the ImageJ program of the colored samples using four backlight colors, to which a principal component analysis was applied using the integrated development environment for R, RStudio. Subsequently, one-way ANOVA and mean comparisons by Tukey's method (α = 0.05) were applied to the best-scoring analytical response's. Ultimately, the quantification of vitamin C in golden berry juice was performed using the image analysis method, which exhibited superior linearity and sensitivity (R2 = 0.9941 and m = 4.91). A comparative assessment was conducted against a spectrophotometric method utilizing the t-Student test for independent samples (α = 0.05), demonstrating no statistically significant difference between the two methods (p > 0.05).