Search

In recent years, wearable flexible sensors have garnered significant attention for their potential in monitoring human physiological signals. Current research focuses on flexible sensors with a wide linear range, high sensitivity, and excellent reliability. Micronanostructures have been introduced to balance these three features to some extent. Inspired by the micronanostructures of human fingerprints, we propose a fingerprint-like flexible sensor that combines polydimethylsiloxane with a grating structure and laser-induced graphene. This fingerprint-like flexible sensor exhibits several desirable characteristics: a wider linear range (0-180°), faster response time (0.3 s), higher sensitivity (688.5 kPa-1), and excellent reliability (>10,000 cycles). These features make fingerprint-like flexible sensors particularly suitable for detecting various human physiological signals, including finger flexion, elbow flexion, finger pressure, and pulse. Therefore, there is considerable potential for integrating multiple fingerprint-like sensors into human physiological signal monitoring applications. This approach offers a promising direction for the future development of wearable flexible sensors. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ionic liquid-based electrochemical biosensors have recently surged to prominence as an intriguing technology with transformative potential for real-time biomolecule monitoring, notably within the dynamic pharmaceutical landscape. By demonstrating their adeptness in detecting an extensive array of biomolecules, encompassing glucose, hormones, nucleic acids, and pivotal biomarkers, these biosensors have substantiated their efficacy in monitoring and detecting biomolecules within the pharmaceutical sphere revealing excellent thermal stability, minimal volatility, and an expansive electrochemical working range. For instance, an electrochemical biosensor comprising a conducting polymer, graphene, gold nanoparticles, and ionic liquids exhibited exceptional sensitivity, with a limit of detection as low as 1 fM (at S/N = 3), a dynamic range of 3.2 fM to 0.32 pM, and remarkable long-term durability for aflatoxin B1 detection. In light of these compelling developments, for the first time, this review offers a comprehensive exploration of recent advancements and emergent trajectories (spanning majorly from 2019 to 2023) in the utilization of ionic liquid-based electrochemical biosensors, particularly in the context of detecting the aforementioned diverse biomolecules pertinent to the pharmaceutical industry. Furthermore, it discusses the challenges and opportunities that lie ahead in the production of these biosensors, shedding light on their potential to reshape the future of pharmaceutical applications.

Copyright of Journal of Electrochemistry is the property of Journal of Electrochemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

为了定量分析亚麻籽油中α-亚麻酸（ALA）顺反异构体，采用SLB-IL111色谱柱，对气相色谱法测定反式亚麻酸（TALA）的分析条件（载气流速和升温程序）进行优化，并对所建立的方法进行评价。结果表明：载气流速选择0.3 mL/min；升温程序为60 ℃保持5 min，以20 ℃/min升温至175 ℃保持15 min，以1 ℃/min升温至180 ℃保持28 min，以0.2 ℃/min升温至185 ℃保持40 min；该方法可实现9c,12t,15t-C18∶ 3和9t,12c,15t-C18∶ 3的较好分离，分离度为0.9，其余各TALA的分离度在1.6~8.7之间；所建立的方法重复性好，测定加热亚麻籽油样时各异构体日间相对标准偏差（RSD）为3.16%~5.65%，日内RSD为2.00%~4.13%，检出限为0.678 2~0.879 0 mg/L，定量限为2.260 6~2.930 1 mg/L；各ALA异构体含量与峰面积之间线性关系良好，相关系数均为0.999 8。综上，所建立的方法可用于亚麻籽油中8种不同构型ALA顺反异构体的定量分析。 In order to quantitatively analyze the cis- and trans- isomers of α-linolenic acid (ALA) in linseed oil, the analytical conditions (carrier gas flow rate and temperature program) for the determination of trans-linolenic acid (TALA) by gas chromatography were optimized on the SLB-IL111 column,and the established method was evaluated. The results showed that the optimal carrier gas flow rate was 0.3 mL/min, and the chromatographic column was initially heated at 60 ℃ for 5 min, then ramped at 20 ℃/min to 175 ℃ and held for 15 min, ramped at 1 ℃/min to 180 ℃ and held for 28 min, finally ramped at 0.2 ℃/min to 185 ℃ and held for 40 min. The method established had effective separation of 9c,12t,15t-C18∶ 3 and 9t,12c,15t-C18∶ 3 with a separation degree of 0.9. The separation degree of the other TALA ranged from 1.6 to 8.7. The method was reproducible and the relative standard deviation (RSD) of inter-day repetition of each isomer in heated lineseed oil was 316%-565%, and the RSD of intra-day was 200%-413%.The detection limit was 0.678 2-0.879 0 mg/L, and the limit of quantification was 2.260 6-2.930 1 mg/L. The linear relationship between the content of each ALA isomer and the peak area was good, and all the correlation coefficient was 0.999 8. In conclusion, the established method can be used for the quantitative analysis of 8 different isomer of ALA in linseed oil.

Fabric-based capacitive pressure sensors have attracted wide attention in smart textiles due to their high sensitivity and fast response advantages. However, there are problems in the optimization study of its performance, such as the difficulty of combining the sensor with fabric and the mutual restriction of high sensitivity and wide linear range. This paper reports a fabric-based capacitive pressure sensor with porous four-phase composites. Microdroplet spraying and liquid-phase reductive deposition techniques were used to spray-print form silver electrodes on a fabric substrate. Meanwhile,multi-walled carbon nanotubes/carbon black/barium titanate-polydimethylsiloxane composite films (MWCNTs/CB/BT-PDMS) with porous structure were obtained as the dielectric layer by using a solution co-mingled casting and sacrificial template method. Benefitting from the high conductivity of the fabric silver electrode, the porous structure of the dielectric layer, and the synergistic effect between the fillers resulted in a sensor with a sensitivity of up to 2.28 kPa−1 (R2 = 0.995) over a wide linear range from 0 to 50 kPa, with the product of the two being 114. In addition, the sensor can accurately monitor various physiological activities of the human body (e.g., respiration monitoring, expression recognition, and joint movement), showing its promising applications in wearable electronic devices. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The cracking behavior of a double-network hydrogel has been studied. • Excellent sensitivity (GF = 2.2) and high linear working range (0–250 % strain) are obtained. • Crack from network ruptures boosts sensor sensitivity. • The crack hydrogel shows outstanding performance for detecting both large and small strain of human body. Recently, owing to their high sensitivity, spider-inspired crack strain sensors have received considerable attention. However, their short linear range leads to severe limitations in their application in sports health monitoring. Herein, we fabricated a cracked hydrogel strain sensor with a wide linear range using κ-carrageenan and polyacrylamide. This crack hydrogel strain sensor has a wide linear range (ε = 250 %) and excellent linearity (R2 ≈ 0.999) while ensuring high sensitivity (gauge factor GF = 2.2). Moreover, this sensor is sensitive to small vibration signals. We compared it with a traditional hydrogel strain sensor and analyzed how crack appeared. Finally, we presented the application of this sensor in human health monitoring and detection of multiaxial strains. [ABSTRACT FROM AUTHOR]

Soft capacitive sensors present numerous appealing characteristics, including simple structure, low power consumption, and fast response. However, they often suffer from low sensitivity and a limited linear sensing range. Herein, a concept is presented to enhance the sensitivity and linearity of supercapacitive pressure sensors by functionally grading the heights of macrodomes constructed from a highly elastic and ionic conductive elastomer made of poly(vinyl alcohol) and phosphoric acid (PVA/H 3 PO 4 ). The resultant supercapacitive sensors exhibit a high sensitivity (423.42 kPa -1 ), wide linear sensing range (0-400 kPa), ultralow limit of detection (0.48 Pa), and high durability (stable signal outputs up to 5000 cycles of loading/unloading). Additionally, the sensors can maintain consistent sensing performance within a temperature range of 25-40 °C. The potential of the sensor in health monitoring is demonstrated through ultrahigh-resolution weight measurement, pulse detection, and respiration monitoring.

• For the first time, novel Fe 2 (MoO 4) 3 /FeS nanocomposite has been successfully synthesized and utilized to fabricate an electrochemical sensor for the detection of homocysteine (Hcy). • The nanocomposite was tailored by a solvothermal synthesis process, resulting in the formation of composite phase without any additional calcination. • The addition of Fe 2 (MoO 4) 3 /FeS nanocomposite significantly enhanced the conductivity of the glassy carbon electrode (GCE) by reducing its resistance. • The Fe 2 (MoO 4) 3 /FeS/GCE demonstrated exceptional electrochemical performance, showcasing the widest linear range (13 μM–9061 μM) and remarkable linearity with LOD value of 0.05 µM. • The wide linear range, which encompasses normal levels of Hcy in blood, demonstrates the potential of this sensor for use in biomedical applications. Here in, we adopted a simplistic approach for the design and tailoring of novel nanocomposite Fe 2 (MoO 4) 3 /FeS (FMO/FeS). The nanocomposite effectively maintains its structural stability, enabling the sensor to work throughout a lengthy linear range. And for the first time, this hybrid material decorated glassy carbon electrode (GCE) utilized for homocysteine (Hcy) quantification. The selective interaction between the material loaded on the electrode surface and -SH group in the homocysteine can be characterized by a variation in the anodic peak and the faster current output. The FMO/FeS facilitate rapid electron transfer between the electrolyte and electrode, allowing for easy detection of homocysteine. The homocysteine undergoes oxidation in the presence of electron acceptor, releasing an electron from thiol group. The extraordinary electrochemical activity attributed by FMO/FeS nanocomposite accelerated the overall performance of sensor towards the selected analyte. The novel sensor illustrated an exceptional linear range of 13–9061 μM for Hcy detection and it is greater than reported in studies till now to the best of our knowledge with limit of detection (LOD) value of 0.05 µM. The reproducibility and repeatability analysis of the unique sensor exhibited admirable results whereas the sensor demonstrated noteworthy selectivity towards desired analyte in the presence of potential interferants. Additionally, the practical application of the sensor assessed by analysing Hcy in blood serum specimen as well as in urine and exhibited remarkable recovery rates. This paving way for the development of comprehensive technologies for proper health care for future. Schematic representation of various steps in the development of homocysteine sensor [Display omitted] [ABSTRACT FROM AUTHOR]

The article discusses a study of a photothermal sensing system for the detection of ochratoxin A (OTA) based on the high selectivity of an aptamer and photothermal effect of the tetramethyl benzidine/hydrogen peroxide colorimetric system. It mentions the use of a common thermometer as a quantitative signal reader in the sensing system. It cites the mediation of the colorimetric system by iron oxide nanoparticles (NP). Also described is the linear range and specificity of the system.

Structural engineers commonly design superstructures as fixed at the base and transmit the reactions to the infrastructure in order to design the foundation system and estimate the displacement of the soil while disregarding the change in seismic response that this induces. In this article, the foundation system was transformed into equivalent springs, and the seismic response in the linear range was compared and quantified, obtaining results such as increased periods, increased amounts of steel reinforcement in beams (between 7% and 25%) and columns (between 29% and 39%), an increase in the number of stirrups per linear meter (between 3% and 11% in columns and between 5% and 45% in beams) and drifts (between 1% and 14%), and a decrease in basal shear (up to 20%), which directly affects the design of the structure. This study concludes that the inclusion of the soil-structure interaction is necessary for structural design in the linear range.

This review article portrays the progress in developing novel electrochemical sensors using morphologically varied transition metal oxides. The role and applications of transition metal oxide nanoparticles of iron, titanium, manganese, zirconium, cobalt, nickel and their composites in the field of electrochemical and bio sensing are conferred in detail. Appropriate chemical functionalization of these nanomaterials guarantees the selective and sensitive determination of target molecules including DNA or creating antigen/antibody complexes. Substantial data is summed up in the tables. This review article highlights the significance of transition metal oxide nanoparticles as promising electrode modifiers for fabrication of sensors. The review ends up with a relevant discussion, existing challenges and future scopes.

• This review introduces biosensors as an ideal strategy for diagnosing Parkinson disease. • This article contains the latest developed biosensors to diagnoses Parkinson's disease. • This paper discusses the diagnostic challenges and limitations of Parkinson's disease. Parkinson's disease (PD) is one of the most critical disorders of the elderly and strongly associated with increased disability, and reduced quality of life. PD is a progressive neurodegenerative disease affecting more than six million people worldwide. Evaluation of clinical manifestations, as well as movement disorders by a neurologist and some routine laboratory tests are the most important diagnostic methods for PD. However, routine and old methods have several disadvantages and limitations such as low sensitivity and selectivity, high cost, and need for advanced equipment. Biosensors technology opens up new diagnoses approach for PD with the use of a new platform that allows reliable, repeatable, and multidimensional identification to be made with minimal problem and discomfort for patients. For instance, biosensing systems can provide promising tools for PD treatment and monitoring. Amongst biosensor technology, electrochemical techniques have been at the frontline of this progress, thanks to the developments in material science, such as gold nanoparticles (AuNPs), quantum dots (QDs), and carbon nanotubes (CNTs). This paper evaluates the latest progress in electrochemical and optical biosensors for PD diagnosis. [ABSTRACT FROM AUTHOR]

In vivo near-infrared (NIR) photoacoustic imaging (PAI) studies using novel contrast agents require validation, often via fluorescence imaging. Bioconjugation of NIR dyes to proteins is a versatile platform to obtain contrast agents for specific biomedical applications. Nonfluorescent NIR dyes with higher photostability present advantages for quantitative PAI, compared to most fluorescent NIR dyes. However, they don’t provide a fluorescence signal required for fluorescence imaging. Here, we designed a hybrid PA-fluorescent contrast agent by conjugating albumin with a NIR nonfluorescent dye (QC-1) and a visible spectrum fluorescent dye, a BODIPY derivative. The new hybrid tracer QC-1/BSA/BODIPY (QBB) had a low minimum detectable concentration (2.5μM), a steep linear range (2.4–54.4 μM; slope 3.39 E -5), and high photostability. Tracer signal was measured in vivo using PAI to quantify its drainage from eye to the neck and its localization in the neck lymph node was validated with postmortem fluorescence imaging.

In this paper, a gain-boosting transconductor with widely input linear range and tunable control voltage is presented. A novel self-biased topology is employed in the negative feedback path of the gain-boosting structure to improve the linearity of the proposed transconductor. In fact, this self-biased topology results in a linear change for the drain voltage of the input drivers under the variation of the control voltage, while the input drivers operate in the triode region. In order to confirm the improved performance of the proposed transconductor, it is employed in a third order Butterworth low pass Gm-C filter. Therefore, the self-biased topology allows having more control on the cutoff frequency of the Gm-C filter. The proposed transconductor is designed and simulated in a 0.18 µm CMOS technology under a 1.8 V power supply. The small signal transconductance of the proposed circuit can change from 2.5 to 104.3 µA/V by tuning the control voltage. In addition, simulation results of the mentioned filter also show that the cutoff frequency properly changes between 500 KHz and 20.6 MHz, while third-order intercept point (IIP3) for this filter is between 7.55 and 21.4 dBm for different applications. [ABSTRACT FROM AUTHOR]

Obtaining accurate experimental data from Lagrangian tracking and tomographic velocimetry requires an accurate camera calibration consistent over multiple views. Established calibration procedures are often challenging to implement when the length scale of the measurement volume exceeds that of a typical laboratory experiment. Here, we combine tools developed in computer vision and non-linear camera mappings used in experimental fluid mechanics, to successfully calibrate a four-camera setup that is imaging inside a large tank of dimensions ∼ 10 × 25 × 6 m 3 . The calibration procedure uses a planar checkerboard that is arbitrarily positioned at unknown locations and orientations. The method can be applied to any number of cameras. The parameters of the calibration yields direct estimates of the positions and orientations of the four cameras as well as the focal lengths of the lenses. These parameters are used to assess the quality of the calibration. The calibration allows us to perform accurate and consistent linear ray-tracing, which we use to triangulate and track fish inside the large tank. An open-source implementation of the calibration in Matlab is available. [ABSTRACT FROM AUTHOR]

Drought stress can significantly affect the yield and quality of tomato production. However, the development of a sensitive and specific method for the determination of drought stress is somehow challenging since plant common morpho-physiological and biochemical characteristic are not generally specific to biotic and abiotic stresses. As a solution, the concentration of miRNAs in plant tissues can be a selective and specific indicator of plant stress. In this study, an optical biosensor based on gold nanoparticles is introduced to determine miRNA-1886 in tomato plant roots. Results showed that irrigation levels from 100% to 60% of field capacity increased the concentration of miRNA-1886 in a range from ca. 100 to 6800 fM (fM) causing a linear change in the biosensor response (R 2 = 0.97). Results also revealed that in contrast with plant conventional morpho-physiological and biochemical characteristic, miRNA-1886 concentration was not significantly affected (P < 0.01) by other stresses, i.e., salinity and temperature during the growth period. The biosensor introduced in this study is a reliable method to study stress-related functions of miRNAs in plants and their application in specific plant stress determination. Image 1 • An AuNPs-based biosensor for ultrasensitive and reliable detection of miRNA-1886. • Comparison of tas14 gene expression and miRNA-1886 in drought conditions. • Introducing miRNA-1886 as a specific indicator of drought stress in tomato. [ABSTRACT FROM AUTHOR]

Copious research has been conducted on Capacitive Pressure Sensors over the decades with a focus on Silicon being the primary filming element. However, due to Silicon Carbide emerging as superior in harsh environmental conditions, the research is gravitating towards it for industrial applications. This work presents a new analytical model for a polycrystalline silicon carbide-based capacitive pressure sensor working in touch-mode operation. Carbide demonstrates properties like electrical stability, mechanical robustness and chemical inertness which puts it on the frontier of research. The mathematical model proposed is a simple yet powerful tool in manipulating design and sizing for fast analysis. It is quicker and bypasses the need for complex simulation software. The analysis is purely mathematical and hence the results are analyzed with MATLAB. The mathematical model developed is verified with a standard Finite Element Analysis (FEM) using COMSOL v5.2. The results of the mathematical analysis dovetail well with the FEM analysis and show a significant improvement in both the sensitivity and capacitance generated. [ABSTRACT FROM AUTHOR]

In order to achieve weak target detection, the range migration and Doppler frequency spread induced by the target motion within the coherent processing interval should be compensated to focus the target energy in a certain range-Doppler cell. This article proposes a new integration method based on non-uniform Keystone transform and non-uniform fast Fourier transform (NUFFT) for random pulse repetition interval (PRI) radar. In this method, non-uniform Keystone transform is applied to correct the linear range migration. After that, the acceleration is estimated by dechirp process and the Doppler frequency spread is compensated. Finally, the target energy is accumulated coherently via NUFFT. Compared with the random PRI generalised Radon-Fourier transform (RPRI-GRFT) and the moving target detection method for random PRI radar, the proposed algorithm achieves a good balance between the detection performance and the computational cost. Simulation results are provided to demonstrate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

High linear MOS varactors can reduce AM to PM conversion and phase noise of the LC-VCOs. In this paper, a new technique is presented to increase the linear range of MOS varactors by reducing the slope of the C–V characteristic in linear region. In the proposed method, instead of using only one MOS varactor with aspect ratio of W/L, several varactors (e.g. n = 2, 3, ...) with (W/n)/L are connected in parallel. The substrate of each varactor is biased at different voltage to shift its C–V linear region by changing the threshold voltage. In this way, each sub-varactor in the proposed structure covers different linear region of the whole varactor. Hence, the overall linear range of the parallel varactors can be significantly increased by correctly biasing of the substrates. To verify the proposed method, a MOS varactor including 6 parallel sub-varactors is designed in a commercial TSMC 0.18 μm CMOS Technology. Simulation results show 4× improvement of the linear range than conventional varactors and nearly constant VCO gain in tuning range. Furthermore, using the proposed varactor in a conventional LC oscillator, 10 dB improvement of the phase noise is achieved. [ABSTRACT FROM AUTHOR]

Bimetal oxide decorated graphene oxide (Bi 2 O 3 /Fe 2 O 3 @GO) was synthesized by a simple hydrothermal method and used as an electrochemical sensor for sensing the toxic cadmium (Cd2+) ion. For comparative analysis graphene oxide (GO), Iron oxide nanoparticle decorated on GO sheets (Fe 2 O 3 @GO) and bismuth oxide nanoparticle decorated on GO sheets (Bi 2 O 3 @GO) were synthesized. Structurally and morphologically two different nanoparticles of Bi 2 O 3 and Fe 2 O 3 on GO sheets were confirmed from XRD, FESEM techniques respectively. Latter the inter planner spacing of the nanoparticles and GO sheets were calculated from the HRTEM techniques, which matched with the exact value obtained through XRD analysis. Functional groups like hydroxyl, epoxide, carbonyl, and carboxyl were investigated through FT-IR techniques. Detection of Cd2+ was performed through square wave voltammetry (SWV) technique with an optimized pH (5.0), deposition potential (−1.0 V) and deposition time (90 s). The Bi 2 O 3 /Fe 2 O 3 @GO modified electrode shows the better electro-catalytic property with more no. of active sites which facilitate the electron transfer between the electrode and species. The nanocomposite Bi 2 O 3 /Fe 2 O 3 @GO was found to be more sensitive than blank, GO, Fe 2 O 3 @GO and Bi 2 O 3 @GO modified electrodes. The Bi 2 O 3 /Fe 2 O 3 @GO modified electrode exhibits a linear range of 6.2 ng L−1 to 1160.2 ng L−1 and limit of detection of 1.85 ng L−1 towards the detection of Cd2+. A very high sensitivity of 2034.2 A cm−2g−1L was recorded for the Bi 2 O 3 /Fe 2 O 3 @GO electrode. The interference study explains the Bi 2 O 3 /Fe 2 O 3 @GO electrode is selective towards Cd2+ among various biomolecules and heavy metal ions. Real sample analysis study confirms the ability of the Bi 2 O 3 /Fe 2 O 3 @GO electrode for detecting Cd2+ present in water, fruits, soil, and biological samples. The Bi 2 O 3 /Fe 2 O 3 @GO electrode has good stability up to 40 days exhibiting without any current loss. • Bi 2 O 3 /Fe 2 O 3 @GO nanocomposite was synthesized for the first time. • Long linear range of 6.2 ng L−1 to 1160.2 ng L−1 was calculated. • Small LOD of 1.85 ng L−1 and sensitivity of 2034.2 A cm−2g−1L was recorded. • Electrode has stability up to 40 days. [ABSTRACT FROM AUTHOR]

Effect of the presence of perforations on thin structure has been extensively investigated for decades. Various perforation parameters were investigated in past studies. However, study on thin cylinder with multiple perforations has not been carried out. In searching for lighter structural members, the concept of perforated hollow section has been inspired by the shape and arrangement of multiple perforations observed in the Cholla skeleton. Effects of multiple perforation parameters on circular hollow section have been the main interest. This paper presents the verification of FEM simulation with test results. A nonperforated circular hollow section (control model) and a circular hollow section penetrated with 12 nos. of circular shape perforations in array arrangement were selected for the verification process. Both test specimen and FEA models were subjected to compression, flexural and torsional loads. For result comparison within the material linear range, FEA models show good agreement with test results for compression and flexural load cases, and for control models under torsional load case. For perforated models under torsional load, FEA results correspond well with the inclined strain gauge readings. FEM analysis method is considered capable to produce reliable result for loading within the material linear range for circular hollow sections with multiple perforations. [ABSTRACT FROM AUTHOR]

The development of sensors for the detection of triacetone triperoxide (TATP) has attracted great attention. Here, we constructed a low-cost, portable, reusable, visible paper-based fluorescent sensor for the sensitive detection of TATP via vapor sampling. Under optimized conditions, the fluorescent film showed a high sensitivity to TATP with a detection limit of lower than 0.5 μg mL−1 in air. The linear range of the response is from 0.5 to 8.0 μg mL−1. In addition, the paper-based sensor exhibited high selectivity to TATP. The presence of potential interferents showed little effect on sensing. Moreover, sensing is fully reversible. Fortunately, the test can also be conducted in a visualized way. [ABSTRACT FROM AUTHOR]

For the quantification of mutated genes at greatly varied concentrations in body fluids, nucleic acid amplification strategies are often challenged by limited dynamic linear ranges. The proposed metal stable isotope detection strategy demonstrates five orders of linear range and a lower attomol detection limit, showing promising potential in clinical diagnosis. [ABSTRACT FROM AUTHOR]

This paper introduces a novel CMOS second-generation current-controlled current conveyor (CCCII) that has a wide tunable intrinsic resistance ( R x ). The designed structure is achieved by the combination of one ordinary CCCII, one cross-coupled OTA and one active resistor. An inverse relationship between the intrinsic resistance and external bias current is created for the first time in CMOS CCCII design, which results in wide tuning range of R x . Performance of the proposed circuit is discussed by detailed analysis. The CMOS CCCII is simulated in TSMC 0.18 μ m RF CMOS technology. The simulation results confirm that the proposed CMOS CCCII achieves a wide tunable R x (from 197.4 Ω to 27.23 k Ω ) while maintaining favorable performance in bandwidth, transfer gain and linear range. In addition, a new reconfigurable structure, which can function as a universal filter or a quadrature oscillator via controlling an enabled switch, is given as an application example to validate the feasibility of the proposed CMOS CCCII. [ABSTRACT FROM AUTHOR]

Abstract Enzymes are highly specific and selective due to their precise, intricate three-dimensional catalytic- structure. Electron transfer in enzymes normally occurs through an active-metal centers or tunneling events that are highly insulated by the surrounding globular protein structure. In case of electrochemically active enzymes/proteins, the distance between the redox-active cofactor and the electrode surface plays key role during direct communication. Therefore, the long electron-tunneling distance can be overcome by introducing mobile redox mediators such as nanostructures specially nanowires which can diffuse into and out of the enzyme active site, ferrying reducing or oxidizing equivalents with them. Therefore, nanowire-conjugated enzymes have gained great interest in the development of biosensor devices and other electrocatalytic-biological applications. Herein we present a comprehensive review about the electrochemical enzyme-based sensor using nanowires. Over the past decade, nanowires were investigated as a versatile platform for various applications including sensors and biosensors because of their high aspect ratio and a high surface-to-volume ratio. This review aimed to summarize some of the recent developments in the enzyme based sensor research that have been achieved with various metallic and non-metallic one-dimensional nanostructure i.e. nanowires. Due to low or no toxicity and biocompatibility, enzymes conjugated with nanowires are still highly specific, sensitive and biologically active. This review demonstrates the potential usability of nanowired-enzymes for the bioanalytical applications. The review includes various types of nanowires, mode of the enzyme integration or immobilization methodologies, probe modification, biosensor fabrication and real or spiked sample testing. Biosensor parameters such as linear range and sensitivity, selectivity and detection limit of reported sensors were also considered herein. We also introduce some of the new nanowire materials which have not yet been used for biosensing or biosensor application. The limitations, challenges and prospects for the use of nanowired-enzymes in electrochemical and other real-time sensing systems as well as fabrication technologies are also discussed in this review. Highlights • Review includes selection, synthesis and immobilization strategies for nanowired enzymes. • Comments and discussion on modification and characterization of nanowired enzyme probes. • Their potential usability for the bioanalytical applications with high accuracy and reliability. • Summary of reported nanowired sensors with respect to detection limit, reproducibility, linear range, long-term enzyme stability. [ABSTRACT FROM AUTHOR]

ABSTRACT The average voidage, radial voidage and axial voidage distribution in ellipsoidal pellets bed layer were studied by experiments and Discrete Element Method (DEM) Simulation. A series of experiments were used to determine the collision parameters of DEM model. The influence of the bed geometry factor on the average voidage and the radial voidage of the bed layer were investigated, the distribution of axial voidage in the bed was observed under different bed height conditions. The results show that the pellet diameter and cylinder diameter are the critical factor affecting the bed voidage distribution. With the bed geometry factor increasing, the average voidage of the bed gradually decreased. When D / d p > 50, the average voidage of the bed approaches to a constant (0.292). The damped oscillation of the radial voidage distributes from the wall toward the center of bed, and there is a maximum value near the wall. When the total height of the bed is constant, ignoring the influence of edge effect, the axial voidage increased gradually and eventually tends to be constant. With the gradual increase of the bed height, the change rate of the voidage and the axial voidage at the same height gradually decreased. Graphical abstract Unlabelled Image Highlights • The distribution of voidage in randomly packed beds with ellipsoidal particles were studied by experiments and DEM. • The linear relations were found between bed geometry factor and average voidage distribution. • The linear relations were found between bed height and axial voidage distribution. • The damped oscillation of the radial voidage distributed from the wall toward the center of bed. [ABSTRACT FROM AUTHOR]