High Linear Range Research Articles

Characterization of lithium diborate, sodium diborate and commercial soda-lime glass exposed to gamma radiation via linearity analyses

The linearity characteristic in radiation dosimetry presents a growing interest. Glasses have been applied to high radiation doses. In this work, materials will be analyzed and compared in relation to their linearity ranges. Lithium diborate, sodium diborate and commercial glass were irradiated with doses from 10 Gy to 10 kGy using a 60Co Gamma-Cell system 220 and evaluated with the UV–vis technique. The sensitivity analyses were applied through four methodologies, searching for linear regions in their response. The results show that all four applied analyses indicate linear regions for the tested radiation detectors. The materials with higher linearity range, in descending order, were lithium diborate, sodium diborate and commercial soda-lime glass. The radiation detectors present potential use for radiation dosimetry in intermediate and high doses.

Topologically protected vortex structures for low-noise magnetic sensors with high linear range

Micromagnetic sensors play a key role in a variety of industries, including the automotive industry, where they are used, for example, for speed and position detection. The adoption of emerging magnetoresistive sensor technology such as anisotropic magnetoresistance, giant magnetoresistance and tunnel magnetoresistance sensors is driven principally by their enhanced sensitivity and improved integration capabilities compared with conventional Hall effect sensors. At the heart of such sensors is a microstructured ferromagnetic thin-film element that transduces the magnetic signal, but these elements often exhibit a nonlinear hysteresis curve and the performance of the sensors is limited by magnetic noise. Here, we examine the origin of magnetic noise in magnetoresistive sensors and show that a topologically protected magnetic vortex state in the transducer element can be used to overcome these limitations. Using analytic and micromagnetic models, we find that the noise is due mainly to irreproducible magnetic switching of the transducer element at external fields that are close to the Stoner–Wohlfarth switching field. Then, using a flux-closed vortex configuration, we develop a giant magnetoresistance sensor layout that, compared to existing state-of-the-art sensors, has lower magnetic noise, a linear regime that is around an order of magnitude higher and negligible hysteresis.

A novel PAPR reduction scheme for VLC DCO-OFDM systems

In this study, we aim to reduce the peak-to-average power ratio (PAPR) for indoor visible light communication (VLC) orthogonal frequency division multiplexing (OFDM) systems and improve the system performance. By utilizing the spatial multiplexing (SMP) technique, we propose a subcarrier spatial grouping (SSG) scheme to address the high PAPR and LED restricted linear range problems. In this scheme, the high-PAPR wideband OFDM signals are partitioned into several low-PAPR narrowband independent signals that are simultaneously transmitted from multiple LED light sources. At the receiver, zero forcing (ZF) is used to reverse the impairments of the channel transform. The computer simulation results demonstrate that the proposed approach achieves lower PAPR and more robustness to LED nonlinearities leading to better bit error rate performance for the same spectral efficiency than that of the conventional DCO-OFDM scheme does in the whole signal-to-noise ratios range.

Reagentless Detection of Low-Molecular-Weight Triamterene Using Self-Doped TiO2 Nanotubes.

TiO2 nanotube electrodes were self-doped by electrochemical cathodic polarization, potentially converting Ti4+ into Ti3+, and thereby increasing both the normalized conductance and capacitance of the electrodes. One-hundred (from 19.2 ± 0.1 μF cm-2 to 1.9 ± 0.1 mF cm-2 for SD-TNT) and two-fold (from ∼6.2 to ∼14.4 mS cm-2) concomitant increases in capacitance and conductance, respectively, were achieved in self-doped TiO2 nanotubes; this was compared with the results for their undoped counterparts. The increases in the capacitance and conductance indicate that the Ti3+ states enhance the density of the electronic states; this is attributed to an existing relationship between the conductance and capacitance for nanoscale structures built on macroscopic electrodes. The ratio between the conductance and capacitance was used to detect and quantify, in a reagentless manner, the triamterene (TRT) diuretic by designing an appropriate doping level of TiO2 nanotubes. The sensitivity was improved when using immittance spectroscopy (Patil et al. Anal. Chem. 2015, 87, 944-950; Bedatty Fernandes et al. Anal. Chem. 2015, 87, 12137-12144) (2.4 × 106 % decade-1) compared to cyclic voltammetry (5.8 × 105 % decade-1). Furthermore, a higher linear range from 0.5 to 100 μmol L-1 (5.0 to 100 μmol L-1 for cyclic voltammetry measurements) and a lower limit-of-detection of approximately 0.2 μmol L-1 were achieved by using immittance function methodology (better than the 4.1 μmol L-1 obtained by using cyclic voltammetry).

Polymeric iron oxide-graphene nanocomposite as a trace level sensor of vitamin C

The nanocomposite of graphene-iron oxide-polyvinyl alcohol (PIG) was synthesized via simple one-pot hydrothermal method and was used in the modification of pencil graphite electrode for developing an electrochemical sensor. Graphene (G) and iron oxide-graphene (IG) composites were synthesized for providing a comparative study. The structural properties of the prepared PIG were studied through X-Ray diffraction (XRD) technique, whereas the morphological analysis was conducted through field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) study. The chemical states of elements present in the prepared composite were confirmed using X-ray photoelectron spectroscopy (XPS) and the functional groups present in the composite were investigated through Fourier transform infrared (FTIR) spectroscopy. The existence of iron oxide nanoparticles along with PVA polymer in PIG composite enhances the electroactive area (0.073 cm2) and roughness factor (0.186) along with the sensitivity of the material. The square wave voltammetry technique was used for detecting the bio-molecule i.e. vitamin C. At optimized condition, the PIG modified electrode shows a high linear range (40 μM–4100 μM), low limit of detection (0.234 μM) and higher sensitivity (1597.03 μA cm−2 mM−1). The PIG material also provides a good stability towards detection of vitamin C.

Quantitative Profiling of Chaperone/Client Interactions with LUMIER Assay.

Chaperones associate with hundreds or thousands of diverse client proteins and regulate their function. Chaperone/client interactions are generally very transient and involve a highly orchestrated assembly and disassembly of regulatory co-factors. This poses specific challenges for identifying and characterizing these interactions in a scalable and sensitive manner. LUMIER assay, which takes advantage of the high sensitivity and linear range of luminescence-based detection, has proven to be an ideal assay to quantitatively profile chaperone/client interactions in a high-throughput manner. This article provides step-by-step instructions for quantitatively profiling these interactions with LUMIER.

Analytical prediction of carbon nanoscroll-based electrochemical glucose biosensor performance

ABSTRACTCarbon nanoscroll (CNS) with extraordinary electrical, physical and optical properties is an ideal candidate on sensor applications. It has great potential in biosensing owing to its outstanding properties like large surface-to-volume ratio, high conductivity, high flexibility and biocompatibility. In this research, we demonstrate a CNS-based biosensor to electrochemically detect glucose with high specificity and sensitivity. To this end, glucose absorption effect on the sensing area in the form of carrier concentration and quantum capacitance variations is investigated. Also, the caused electrical response on CNS as a detection element is analytically proposed, in which significant current increase of the CNS-based biosensor is observed after exposure to glucose. The proposed CNS-based glucose biosensor exposes higher current compared to that of carbon nanotube counterpart for analogous ambient conditions. Moreover, the comparative results provide evidence of good consensus between the model and experimental data of platinum nanoparticles/graphene nanoscrolls (Pt/GSS) and Pt/nitrogen-doped GSS (Pt/N-GSS) nanocomposites-based biosensors. Main findings of this research can be served as a high throughput platform to analytically predict the behaviour of the sensing mechanism in glucose biosensors. The results further reveal that the CNS biosensor demonstrates not only high sensitivity and broad linear range but also long-term stability and low detection limit.

A new hybrid TDC based on GRO-pseudo delay architecture with fractional code and wide time range detection for divider-less ADPLL

This paper presents a novel Time-to-digital converter (TDC) for All Digital Phase Locked Loop (ADPLL) able to reach high linearity and wide input range with normalized fractional output code. The topology is based on startable Pseudo differential delay cells. It arbiters in a gated ring oscillator (GRO) format in manner to extend measurement time interval. A normalization unit is developed to free calibrate output and to measure phase errors for divider-less ADPLL applications. The proposed TDC is designed in 90 nm CMOS process. Simulation results show that the TDC achieves a large detectable conversion range that extends between 0.285 and 10 ns. The attained time resolution is 9.4 ps, which corresponds to half the delay time of an inverter. The TDC is self-calibrating with estimated accuracy better than 0.28%. The structure consumes 6.6 mA current from a 1.0 V voltage supply, when operating at a clock frequency of 13 MSPS. The estimated differential nonlinearity and integral nonlinearity are ±0.48 LSB and ±0.6 LSB respectively. Compared to previously reported TDC, this implementation achieves a competitive FoMP without requiring complicate calibration.

One pot synthesis of carboxyl functionalized-polyhedral oligomeric siloxane based monolith via photoinitiated thiol-methacrylate polymerization for nano-hydrophilic interaction chromatography

A hybrid monolith exhibiting almost retention independent separation performance in hydrophilic interaction chromatography (HILIC) was obtained by one-pot photoinitiated thiol-methacrylate polymerization. Polyhedral oligomeric silsesquioxane containing methacrylate units (POSS-MA) was used as the main monomer and crosslinking agent, together with a hydrophilic ligand with two carboxyl groups, mercaptosuccinic acid (MSA) as the thiol agent and chromatographic ligand. The isocratic separation of nucleosides, nucleotides and organic acids on MSA attached-poly(POSS-MA) monolith was investigated in HILIC mode. The van-Deemter plots for obtained for nucleosides, nucleotides and benzoic acids clearly showed that there were two regions in each graph with two different slopes in the studied range of linear flow rate (i.e. 0.2–4.3mm/s). The slope of plate height-linear velocity curve was so small in the low linear velocity region between 0.2–2.1mm/s while the slope in high linear velocity region between 2.1–4.3mm/s was so higher with respect to the first region. The van-Deemter plots sketched for all analyte grous used in HILIC mode obeyed this tendency Almost “retention independent plate height behavior” was demonstrated in HILIC, using nucleotides, nucleotides or benzoic acids as the analytes in the linear velocity range of 0.2–2.1mm/s. This behavior was explained by the porous structure of the synthesized monolith facilitating the convective transport of analytes. The variation of plate height was not retention-independent within high linear velocity range (>3.2mm/s) when nucleosides were separated in HILIC mode.

Coplanar Waveguide Transmission Line Loaded With Electric-LC Resonator for Determination of Glucose Concentration Sensing

In this paper, a compact glucose concentration sensor is designed based on an electric-LC (ELC) resonator coupled with a coplanar waveguide (CPW) transmission line, and the ELC resonator is no longer aligned with the CPW transmission line axis. The principle of the sensor is based on the notch depth in the transmission coefficient (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> ) depending on the glucose concentration, and it is applied using a micropipette into a cylindrical plastic sample chamber that covers the gap in the middle branch of the ELC resonator. The notch magnitude in the transmission coefficient response behavior was measured and analyzed in the range of 2.5-6 GHz with air, deionized water, phosphate buffered saline (PBS), and different glucose concentrations in deionized water and PBS in the range of 0%-20% (w/V). The experimental results showed that the proposed sensor has good detection of the glucose concentration with high linearity and wide dynamic range. A prototype of the sensor provides an opportunity for the development of a biological and chemical sensing application in the future.

Electro Catalytic Properties of α, β, γ, ϵ ‐ MnO2 and γ ‐ MnOOH Nanoparticles: Role of Polymorphs on Enzyme Free H2O2 Sensing

AbstractPolymorphs of Manganese di oxide (MnO2) such as alpha (α), beta (β), gamma (γ), epsilon (ϵ), and MnOOH type materials were prepared via hydrothermal approach under different conditions. The samples were characterized by XRD, FESEM, FT‐IR, Raman and BET analysis. Cyclic voltammetry (CV) analysis confirm that α ‐ MnO2 shows better electro‐catalytic ability. Amperometry sensing of hydrogen peroxide (H2O2) was carried out by varying applied potential value with the polymorphs of MnO2. Compared with the other phases of MnO2, α ‐ MnO2 shows high linear range up to 20μM. The calculated sensitivity value for H2O2 sensing of different phases is in the order of α ‐ MnO2, β ‐ MnO2, ϵ ‐ MnO2, γ ‐ MnO2, MnOOH and found to be 0.094 mA μM−1 cm−2 &gt; 0.072 mA μM−1 cm−2 &gt; 0.07 mA μM−1 cm−2 &gt; 0.03 mA μM−1 cm−2 &gt; 0.01 mA μM−1 cm−2 respectively. All the characterization results reveal that crystalline phase plays a vital role in electrochemical behavior rather than crystalline size, morphology, surface charge, surface area.

Tailored liquid chromatography–mass spectrometry analysis improves the coverage of the intracellular metabolome of HepaRG cells

Metabolomics protocols are often combined with Liquid Chromatography-Mass Spectrometry (LC–MS) using mostly reversed phase chromatography coupled to accurate mass spectrometry, e.g. quadrupole time-of-flight (QTOF) mass spectrometers to measure as many metabolites as possible.In this study, we optimised the LC–MS separation of cell extracts after fractionation in polar and non-polar fractions. Both phases were analysed separately in a tailored approach in four different runs (two for the non-polar and two for the polar-fraction), each of them specifically adapted to improve the separation of the metabolites present in the extract. This approach improves the coverage of a broad range of the metabolome of the HepaRG cells and the separation of intra-class metabolites.The non-polar fraction was analysed using a C18-column with end-capping, mobile phase compositions were specifically adapted for each ionisation mode using different co-solvents and buffers. The polar extracts were analysed with a mixed mode Hydrophilic Interaction Liquid Chromatography (HILIC) system. Acidic metabolites from glycolysis and the Krebs cycle, together with phosphorylated compounds, were best detected with a method using ion pairing (IP) with tributylamine and separation on a phenyl-hexyl column.Accurate mass detection was performed with the QTOF in MS-mode only using an extended dynamic range to improve the quality of the dataset. Parameters with the greatest impact on the detection were the balance between mass accuracy and linear range, the fragmentor voltage, the capillary voltage, the nozzle voltage, and the nebuliser pressure.By using a tailored approach for the intracellular HepaRG metabolome, consisting of three different LC techniques, over 2200 metabolites can be measured with a high precision and acceptable linear range. The developed method is suited for qualitative untargeted LC–MS metabolomics studies.

One-step determination of lead over a higher linear range by an artificial neural network after air-assisted liquid–liquid microextraction coupled to flame atomic absorption spectrometry

A simple and rapid method was proposed for the preconcentration of trace levels of lead prior to its determination by flame atomic absorption spectroscopy, based on air-assisted liquid–liquid microextraction.

Malachite Green and Leuco-Malachite Green Detection in Fish Using Modified Enzyme Biosensor

A modified enzyme-based biosensor was developed for amperometric measurement of total Malachite Green (sum of MG and LMG) in tilapia fish. The 4 UmL-1 butyrylcholinesterase enzyme (BuChE) was used and immobilized onto the surface of carbon paste electrode during the electro-polymerization of polypyrrole (PPy). It is a simple, rapid and sensitive technique used for determination of total MG using 0.1M phosphate buffer pH 8.0. In this study, butyrylthiocholine iodide (0.3 Mm BTCi) was used as a substrate which produced the thiocholine due to the enzymatic hydrolysis. Then, it was oxidized at 0.4V against silver-silver chloride electrode for 100 s. The modified enzyme biosensor provided a high sensitivity and linear concentration range from 0.25 to 10 ppb with a limit of detection (LOD) at 0.25 ppb. The results showed the linear standard curve of total MG standard solution (based on the current output in microampere) with the equation of y = - 0.9113x + 10.84, R2 = 0.9445.

Bioluminescent Ligand-Receptor Binding Assays for Protein or Peptide Hormones.

Bioluminescence has been widely used in biomedical research due to its high sensitivity, low background, and broad linear range. In recent studies, we applied bioluminescence to ligand-receptor binding assays for some protein or peptide hormones based on a newly developed small monomeric Nanoluciferase (NanoLuc) reporter that has the so far brightest bioluminescence. The conventional ligand-receptor binding assays rely on radioligands that have drawbacks, such as radioactive hazards and short shelf lives. In contrast, the novel bioluminescent binding assays use the NanoLuc-based protein or peptide tracers that are safe, stable, and ultrasensitive. Thus, the novel bioluminescent ligand-receptor binding assay would be applied to more and more protein or peptide hormones for ligand-receptor interaction studies in future. In the present article, we provided detailed protocols for setting up the novel bioluminescent ligand-receptor binding assays using two representative protein hormones as examples.

Monte Carlo simulation of ionizing radiation induced DNA strand breaks utilizing coarse grained high-order chromatin structures

Ionizing radiation threatens genome integrity by causing DNA damage. Monte Carlo simulation of the interaction of a radiation track structure with DNA provides a powerful tool for investigating the mechanisms of the biological effects. However, the more or less oversimplification of the indirect effect and the inadequate consideration of high-order chromatin structures in current models usually results in discrepancies between simulations and experiments, which undermine the predictive role of the models. Here we present a biophysical model taking into consideration factors that influence indirect effect to simulate radiation-induced DNA strand breaks in eukaryotic cells with high-order chromatin structures. The calculated yields of single-strand breaks and double-strand breaks (DSBs) for photons are in good agreement with the experimental measurements. The calculated yields of DSB for protons and α particles are consistent with simulations by the PARTRAC code, whereas an overestimation is seen compared with the experimental results. The simulated fragment size distributions for 60Co γ irradiation and α particle irradiation are compared with the measurements accordingly. The excellent agreement with 60Co irradiation validates our model in simulating photon irradiation. The general agreement found in α particle irradiation encourages model applicability in the high linear energy transfer range. Moreover, we demonstrate the importance of chromatin high-order structures in shaping the spectrum of initial damage.

Exploiting charge/ions compensating processes in PANI/SPANI/reduced graphene oxide composite for development of a high sensitive H2O2 sensor

The present work describes the development of a polyaniline/polyaniline-2-sulfonic acid/reduced graphene oxide composite (PANI/SPANI/rGO) modified electrode by electropolymerization to detection of hydrogen peroxide. The ionic transport at the PANI/SPANI/rGO film was evaluated by the investigation of the protonic and anionic participation in the charge compensation processes. The sulfonic group and reduced graphene oxide in the composite film contribute to suppression of the anionic transportation and improve the composite ability to fixing cytochrome c redox protein (Cytc). The ability of the PANI/SPANI/rGO film in absorbing the Cytc resulted in a high sensitivity (0.45μALμmol−1), high linear range (from 0.1μmolL−1 up to 1000μmolL−1) and low limit of detection (0.04μmolL−1) to hydrogen peroxide. Indeed, the hybrid organic–inorganic sensor exhibited a good reproducibility and stability to H2O2 reduction at an applied potential of −200mV vs. Ag/AgCl.

Ultrasound assisted microextraction-nano material solid phase dispersion for extraction and determination of thymol and carvacrol in pharmaceutical samples: experimental design methodology.

In the present study, for the first time, a new extraction method based on "ultrasound assisted microextraction-nanomaterial solid phase dispersion (UAME-NMSPD)" was developed to preconcentrate the low quantity of thymol and carvacrol in pharmaceutical samples prior to their HPLC-UV separation/determination. The analytes were accumulated on nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) that with more detail identified by XRD, FESEM and UV-vis technique. Central composite design (CCD) combined with desirability function (DF) was used to search for optimum operational conditions. Working under optimum conditions specified as: 10 min ultrasonic time, pH 3, 0.011 g of adsorbent and 600 μL extraction solvent) permit achievement of high and reasonable linear range over 0.005-2.0 μg mL(-1) (r(2)>0.9993) with LOD of thymol and carvacrol as 0.23 and 0.21 μg L(-1), respectively. The relative standard deviations (RSDs) were less than 4.93% (n=3).

Highly linear and large spring deflection characteristics of a Quasi-Concertina MEMS device

In this work a Quasi-Concertina (QC) spring capable of a high linear range, large deflections, high out-of-plane compliance, and low in-plane compliance for MEMS applications is presented. These features are essential for high accuracy out-of-plane measurements such as those required in self-sensing nanoindentation atomic force microscopy (AFM) probes or molecular mass sensors. The spring constant and first mode resonant frequency of the spring was determined analytically and verified numerically. The QC springs were microfabricated using a purposely developed stiction free process. Force–displacement tests on the QC springs have shown them to be in good agreement with the analytical and finite element analysis performed. The measurement results show that the QC springs fabricated have an out-of-plane spring constant of 5.5N/m, 0.129N/m, and 0.156N/m, remain 99% linear to a deflection of 100μm, 1080μm, and 931μm respectively, and can have a total deflection before fracture of as much as 8000μm.

Single transistor high linearity and wide dynamic range active inductor

SummaryIn this paper, an active inductor (AI) with high linearity and high dynamic range, including a minimum number of components, is presented. The AI is composed by a single transistor, and by a passive compensation network; the latter allows the control of the values of both the inductance and the series resistance.In order to show the feasibility of the proposed AI for filter applications, a prototype board on a TLX8 substrate with a first‐order active band‐pass filter has been fabricated and tested. The filter has a center frequency of 2470 MHz (useful for Bluetooth applications) and a measured noise figure (NF) of 9 dB with a −5 dBm P1dB compression point, and a 75 dB dynamic range. Copyright © 2013 John Wiley &amp; Sons, Ltd.