Entire Dynamic Range Research Articles

The dynamic range of immunoassays for heparin-induced thrombocytopenia

BackgroundFollowing the current guidelines, immunoassays for the diagnosis of heparin-induced thrombocytopenia (HIT) are interpreted dichotomously, with test results categorized as either positive or negative. However, the extent to which test results hold diagnostic significance across the entire dynamic range remains unclear. ObjectivesWe utilized data from the prospective TORADI-HIT study, comprising 1,393 consecutive patients with suspected HIT, to assess the diagnostic significance of two H/PF4 immunoassay test results across their respective dynamic ranges: HemoSil Acustar HIT IgG [CLIA] and Lifecodes PF4 IgG [ELISA]. MethodsHIT diagnosis was determined by a washed-platelet heparin-induced platelet activation assay (HIPA). For each measurement point in the dataset, we computed likelihood ratios (LR), sensitivities, and specificities. To provide post-test probabilities for individual test results, we calculated interval-specific likelihood ratios and integrated it into a web-based calculator. ResultsThe prevalence of HIT was 8.5% (n = 119). A likelihood ratio of ≥ 10 was first achieved at 0.3% of the dynamic range (0.4 U/ml; CLIA) and 16% (0.64 OD; ELISA), respectively. A likelihood ratio of ≥ 100 was present at 9.4% (12 U/ml; CLIA) and 75.0% (3.0 OD; ELISA). The slope of the linear regression line (LR ∼ dynamic range) was 9.5 (CLIA) and 0.9 (ELISA). ConclusionDespite both immunoassays showing an association between results and diagnostic significance, the strength of that association varies by assay. CLIA has a larger increase per measurement unit. Post-test probabilities for individual patients can be estimated using a web-based calculator: https://pcd-research.shinyapps.io/BayesianCalculator/.

Characterization of the Small Robotic Telescope Instrument and Implementation at ITERA Lampung Astronomical Observatory

As time has passed, the technological advances used to run these telescope systems have become faster, more reliable, and more user-friendly. Institut Teknologi Sumatera (ITERA) has installed a small robotic telescope at the Meteorology–Climatology–Geophysics Observing Station in collaboration with an ASTELCO System. The telescope system is designed to make fully robotic observations and can operate in both interactive and unattended robotic modes. This study's primary focus is on the OZT-ALTS telescope robotic system with the optical system using triplet apochromatic lens technology manufactured by LZOS with a focal ratio of f/8 refractor design. The telescope mount is a German Equatorial (NTM-500 manufactured by ASTELCO) with a direct drive system with an absolute encoder, and it allows fully programmable tracking speeds with a typical slewing speed of 20°/sec and a tracking accuracy range of 0.3–1.0 arcsec. For the process of collecting moon observation images, we use Manta G-031B. The OZT-ALTS robotic telescope is now contributing to monitoring crescent moon observation and astronomical studies. This paper presents the scientific motivation behind the OZT-ALTS robotic telescope and the facility's specifications and unique features. Furthermore, we present to characterize the result of the hardware OZT-ALTS robotic telescope system to increase the mechanical and optical performance of the telescope system based on the in-situ test observations. Based on the result, setting the Gain on the camera at 3.5 e-/ADU is the limit for the CCD to produce good-quality output images by utilizing the entire dynamic range without saturation. We also present an example of the science we have performed with the OZT-ALTS robotic telescope. The OZT-ALTS can observe young crescent moon events in the daylight after implementing the CLAHE technique to enhance contrast objects. On the other hand, the OZT-ALTS can also observe WASP-16b and WASP-34b exoplanets by using the transit method to analyze the decreasing light curve when a planet passes between a star and its observer.

Underwater image enhancement using contrast correction

AbstractLight‐induced degeneration of underwater images occurs by physical features of seawater. According to the wavelength of the colour spectrum, light reduces intensity significantly when it moves through water. The greatest wavelength of light that is visible gets absorbed first. Red and blue absorb the most and least, respectively. Because of the reducing consequences of the light spectrum, underwater images having poor contrast can be obtained. As a result, the crucial data contained inside these images will not be effectively retrieved for later analysis. The recent research suggests a novel approach to enhance the contrast while decreasing noise in underwater images. The recommended approach involves image histogram transformation using two significant colour spaces, Red‐Green‐Blue (RGB) and Hue‐Saturation‐Value (HSV). The histogram of the dominant colour channel (blue channel) in the RGB colour model is extended towards the lower level, containing a maximum limitation of 95%, while the inferior red colour channel has been extended towards the upper side, containing a minimum limitation of 5%. During the entire dynamic range, the green colour channel having the dominant and inferior colour channels expands in each direction. The Rayleigh distribution has been utilized for developing various stretching actions within the RGB colour space. The image has been converted to the HSV colour space, having the S and V elements adjusted within 1% of their minimum and maximum values. The suggested approach is examined in both qualitative and quantitative analysis. According to qualitative analysis, the recommended approach substantially boosts image contrast, lowers its blue and green effect, and minimizes over‐enhanced and under‐enhanced sections in the final resultant underwater image. The quantitative examination of 500 large scale underwater images dataset reveals that the suggested technique generates better results. The dataset images are grouped into small fish images, blue coral images, stone wall images, and coral branch images. The quantitative examination of all these four groups have been evaluated and shown. The average mean square error, peak signal to noise ratio, underwater image quality measurement, and underwater colour image quality evaluation values of dataset images are 76.69, 31.25, 3.85, and 0.64, respectively. These values of our proposed work outperform six other previous methods.

Flow investigation of two-stand ultrasonic flow meters in a wide dynamic range by numerical and experimental methods

The enhancement of two-stand ultrasonic flow meters relies upon obtaining a precise understanding and prediction of their complex flow physics throughout their entire dynamic range of operation. This study provides a comprehensive numerical and experimental investigation of the flow physics of a typical two-stand ultrasonic flow meter by industry standards. Predictions based on computational fluid dynamics simulations are employed to obtain numerical results, which are validated through experiments based on laser Doppler velocimetry and static pressure drop. Results indicate that no qualitative changes occur beyond an inflow Reynolds number of 104 in terms of coherent structures and flow dynamics. Analysis of the static pressure distribution across cross-sections reveals that the stands are the most influential areas contributing to pressure drop. In cases with turbulent inflow, there is a noticeable recovery of static pressure following significant pressure gradients across the stands, while such recovery is absent in scenarios with laminar inflow. Both numerical and experimental approaches yield excellent agreement in outcomes, accurately estimating the axial velocity within the flow meter’s measurement volume and the pressure drop across it, with deviations within experimental uncertainty ranges of 2 standard deviations. The developed numerical methodology demonstrates its potential to accurately evaluate complex internal-flow systems with similar flow features and Reynolds number ranges. The flow dynamics for a wide dynamic range of operation in two-stand ultrasonic flow meters are shown in detail in both laminar and turbulent flow regimes, displaying rolling vortices, detached flow, and recirculation zones.

Output Ripple Voltage Analysis of Quadratic Buck–Boost Converters with Switched Inductor Network in the Entire Dynamic Range

In order to provide theoretical guidance for the design of quadratic Buck–Boost converter with switched inductor network, the minimum current flowing through the energy storage inductor L 3 is compared with the output current and zero, the working mode of the converter can be divided into the complete inductor supply in continuous conduction mode(CISM-CCM), the incomplete inductor supply in continuous conduction mode(IISM-CCM)and the incomplete inductor supply in discontinuous conduction mode(IISM-DCM). Within the given input voltage and load range, the working region of the converter is divided into five parts according to the different value of the inductor L 3. By analyzing the output ripple voltage of the converter in the five working areas, and the maximum output ripple voltage of the converter is obtained. Based on the relationship between the maximum output ripple voltage of the entire dynamic range and the value of the inductor L 3, it is pointed out that the output voltage ripple of the converter in CISM-CCM is the smallest and independent of the inductor L 3, and that the output voltage ripple in IISM-CCM and IISM-DCM is much larger and increasing with the decreasing of the inductor L 3. Meanwhile, it is concluded that the minimum inductance to guarantee the lowest output ripple voltage is the critical inductance between CISM-CCM and IISM-CCM. Finally, the experimental results verify the rationality and correctness of the theoretical analysis.

Single‐Mode Electrically Pumped Terahertz Laser in an Ultracompact Cavity via Merging Bound States in the Continuum

AbstractPhotonic bound states in the continuum (BICs) are highly localized optical modes that have found important applications in lasers, sensors, modulators, and harmonic signal generators. While possessing a higher quality factor (Q) as compared to leaky photonic modes, regular BICs (e.g., either symmetry‐protected or accidental BICs) normally require large cavity sizes and are usually sensitive to the fabrication imperfections that introduce lattice disorders. Moreover, the previous demonstrations of BIC lasers are mostly based on optical pumping and operated in the visible and near‐infrared regimes. Here, an electrically pumped BIC laser is demonstrated by merging two types of BIC modes based on a quantum cascade chip in the terahertz (THz) regime, which has an ultra‐compact size (with a pump area around 4λ2). The measured side‐mode suppression ratio (SMSR) can reach up to ≈20 dB, indicating a good single‐mode performance over the entire dynamic range. In addition, the emitted beam shows a nontrivial cylindrical vector beam profile, a typical topological feature of BIC lasers. This work would pave the way for practical use of the emerging BIC concepts in pursuing ultra‐compact and high‐performance electrically driven laser sources, which are highly desired in advanced optoelectronics and integrated photonics.

Wind-fed GRMHD simulations of Sagittarius A*: tilt and alignment of jets and accretion discs, electron thermodynamics, and multiscale modelling of the rotation measure

ABSTRACTWind-fed models offer a unique way to form predictive models of the accretion flow surrounding Sagittarius A*. We present 3D wind-fed magnetohydrodynamic (MHD) and general relativistic magnetohydrodynamic (GRMHD) simulations spanning the entire dynamic range of accretion from parsec scales to the event horizon. We expand on previous work by including non-zero black hole spin and dynamically evolved electron thermodynamics. Initial conditions for these simulations are generated from simulations of the observed Wolf–Rayet stellar winds in the Galactic Centre. The resulting flow tends to be highly magnetized (β ≈ 2) with an ∼r−1 density profile independent of the strength of magnetic fields in the winds. Our simulations reach the magnetically arrested disc (MAD) state for some, but not all cases. In tilted flows, standard and normal evolution (SANE) jets tend to align with the angular momentum of the gas at large scales, even if that direction is perpendicular to the black hole spin axis. Conversely, MAD jets tend to align with the black hole spin axis. The gas angular momentum shows similar behaviour: SANE flows tend to only partially align while MAD flows tend to fully align. With a limited number of dynamical free parameters, our models can produce accretion rates, 230 GHz flux, and unresolved linear polarization fractions roughly consistent with observations for several choices of electron heating fraction. Absent another source of large-scale magnetic field, winds with a higher degree of magnetization (e.g. where the magnetic pressure is 1/100 of the ram pressure in the winds) may be required to get a sufficiently large rotation measure with consistent sign.

Room-temperature continuous-wave InP-based 2.01 µm microcavity lasers in whispering-gallery modes with InGaAsSb quantum well

We demonstrated an electrically pumped InP-based microcavity laser operating in continuous-wave mode. The active region is designed with antimony surfactants to enhance the gain at 2 μm, and a selective electrical isolation scheme is used to secure continuous-wave operation for the microcavity laser at room temperature. The lasers were fabricated as a notched elliptical resonator, resulting in a highly unidirectional far-field profile with an in-plane beam divergence of less than 2°. Single-mode emission was obtained over the entire dynamic range, and the laser frequencies were tuned linearly with the pumping current. Overall, these directional lasers pave the way for portable and highly integrated on-chip sensing applications.

PSUN51 Re-Calibrating Aldosterone Assay Interpretations: Immunoassay and Liquid Chromatography-Tandem Mass Spectrometry Measurements Across Multiple Controlled Physiologic Conditions

Abstract Background Clinicians frequently rely on aldosterone thresholds derived from older immunoassays to diagnose primary aldosteronism. However, liquid chromatography tandem mass spectrometry (LC-MS/MS) is in increasingly widespread clinical use and has been reported to yield lower aldosterone concentrations. Given that primary aldosteronism is highly prevalent and morbid, yet rarely diagnosed, incorrect interpretations of aldosterone levels can have significant public health impact. To address the potential for incorrect interpretations across the entire dynamic range of aldosterone physiology, we compared aldosterone measurements using LC-MS/MS and immunoassay under controlled physiologic conditions. Methods Untreated, normotensive, overweight volunteers (n=48) underwent prospective characterization of aldosterone production during four controlled conditions: oral sodium suppression and dietary sodium restriction (to capture the full range of Angiotensin II-mediated aldosterone production) and dexamethasone suppression and cosyntropin stimulation (to capture the full range of ACTH-mediated aldosterone production). Serum aldosterone from each condition (n=188 samples) was measured by both immunoassay and LC-MS/MS. Results Serum aldosterone concentrations by LC-MS/MS and immunoassay had a Pearson correlation of 0.69 (p<0.001), with good agreement (intraclass correlation coefficient 0.76 [95% CI 0.52-0.87]). Overall, aldosterone was 37.2% lower by LC-MS/MS than immunoassay (median 10.5 [IQR 3.8, 21.9] vs. 19.6 [9.5, 28.0] ng/dL; p<0.001) with an average bias of 7.2 (SD 12.0) ng/dL by Bland-Altman analysis. The most notable discrepancy was observed in the clinically discriminatory range below 20 ng/dL: 9.9 [7.1, 13.8] ng/dL by immunoassay corresponded to 5.5 [1.4, 8.9] ng/dL by LC-MS/MS (p<0.001), a median difference of 49.6% [20.6, 75.2%] higher by immunoassay. Following oral sodium suppression testing, the aldosterone-to-renin ratio was 4-fold higher by immunoassay than by LC-MS/MS (27.2 [19.7, 62.4] vs. 6.4 [3.5, 19.1] ng/dL per ng/mL/h; p<0.001). Conclusions Aldosterone measurements are systematically lower by LC-MS/MS than by immunoassay across the entire physiologic spectrum of aldosterone production; this effect was especially pronounced – up to 50-65% lower – when aldosterone levels were less than 20 ng/dL, meaning that clinicians should be careful to verify the assay used and the clinical context before excluding the diagnosis of primary aldosteronism. Our findings highlight the risk for false negative interpretations with increasingly common LC-MS/MS assays, thereby underscoring the urgent need to raise awareness among clinicians that interpretations of circulating aldosterone and aldosterone-to-renin ratio values need to be re-calibrated to include much lower values than previously recommended. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

In Vivo Optogenetics Reveals Control of Cochlear Electromechanical Responses by Supporting Cells.

Cochlear sensitivity, essential for communication and exploiting the acoustic environment, results from sensory-motor outer hair cells (OHCs) operating in a structural scaffold of supporting cells and extracellular cortilymph within the organ of Corti (OoC). Cochlear sensitivity control is hypothesized to involve interaction between the OHCs and OoC supporting cells (e.g., Deiters' cells [DCs] and outer pillar cells [OPCs]), but this has never been established in vivo Here, we conditionally expressed channelrhodopsins (ChR2) specifically in male and female mouse DCs and OPCs. Illumination of the OoC activated the nonselective ChR2 cation conductance and depolarized DCs when measured in vivo and in isolated OoC. Measurements of sound-induced cochlear mechanical and electrical responses revealed that OoC illumination suppressed the normal functions of OoC supporting cells transiently and reversibly. OoC illumination blocked normally occurring continuous minor adjustments of tone-evoked basilar membrane displacements over their entire dynamic range and OHC voltage responses to tones at levels and frequencies subject to cochlear amplification. OoC illumination altered the OHC mechanoelectrical transduction conductance operating point, which reversed the asymmetry of OHC voltage responses to high level tones. OoC illumination accelerated recovery from temporary loud sound-induced acoustic desensitization. We concluded that DCs and OPCs are involved in both the control of cochlear responses (which are essential for normal hearing) and the recovery from temporary acoustic desensitization. This is the first direct in vivo evidence for the interdependency of the structural, mechanical, and electrochemical arrangements of OHCs and OoC supporting cells that together provide fine control of cochlear responses.SIGNIFICANCE STATEMENT A striking feature of the mammalian cochlear sensory epithelium, the organ of Corti, is the cellular architecture and supporting cell arrangement that provides a structural scaffold for the sensory-motor outer hair cells. The role of the supporting cell scaffold, however, has never been elucidated in vivo, although in vitro and modeling studies indicate the scaffold is involved in exchange of forces between the outer hair cells and the organ of Corti. We used in vivo techniques, including optogenetics, that do not disrupt arrangements between the outer hair cells and supporting cells, but selectively, transiently, and reversibly interfere with supporting cell normal function. We revealed the supporting cells provide continuous adjustment of cochlear sensitivity, which is instrumental in normal hearing.

Calibration methods for charge integrating detectors

Since the introduction of the extremely intense X-ray free electron lasers, the need for low noise, high dynamic range and potentially fast charge integrating detectors has increased significantly. Among all the problems that research and development groups have to face in the development of such detectors, their calibration represents one of the most challenging and the collaboration between the detector development and user groups is of fundamental importance. The main challenge is to develop a calibration suite that is capable to test the detector over a wide dynamic range, with a high granularity and a very high linearity, together with a certain radiation tolerance and the possibility to well define the timings and the synchronization with the detector. Practical considerations have also to be made like the possibility to calibrate the detector in a reasonable time, the availability of the calibration source at the experimental place and so on. Such a calibration test suite is often not represented by a single source but by several sources that can cover different parts of the dynamic range and that need to be cross calibrated to have a final calibration curve. In this respect an essential part of the calibration is also to develop a mathematical model that allows calibrating the entire dynamic range, taking into account features that are calibration source and/or detector specific. The aim of this contribution is to compare the calibration for the AGIPD detector using several calibration sources such as internal current source, backside pulsing, IR pulsed laser, LED light and mono-energetic protons. The mathematical procedure used to calibrate the different sources will be discussed in great detail showing how to take into account a few shortcomings (like pixel coupling) that are common for many charge integrating detectors. This work has been carried out in the frame of the AGIPD project for the European X-ray Free Electron Laser.

Offset and Gain FPN Calibrated Linear-Logarithmic Image Sensor With Shared Pixel Architecture

This brief presents offset and gain FPN calibrated linear-logarithmic image sensor. Offset FPN originated from threshold voltage variation of the logarithmic conversion transistor is calibrated with Two-step charge transfer operation. Remaining gain FPN is analyzed and its root cause is investigated. The subthreshold slope difference of the logarithmic conversion transistors in the shared pixel architecture is found to be responsible for the increasing FPN in the logarithmic operation region and potentially limiting dynamic range in high illumination region. A simple modeling-based gain FPN correction method in linear-logarithmic APS using shared pixel architecture has been proposed. The prototype sensor is fabricated by using a 0.13- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS image sensor process. Thanks to the proposed gain FPN correction together with offset correction using Two-step charge transfer operation, wide dynamic range of more than 120 dB has been achieved while maintaining the total FPN less than 0.29% over the entire dynamic range.

Interval‐specific likelihood ratios for improving differential diagnosis of Alzheimer’s disease using biomarkers in cerebrospinal fluid

AbstractBackgroundSingle cutoff values are currently applied to interpret Alzheimer biomarker results. Yet these cutoffs are not uniform among centers, nor highly specific to discriminate AD from other disorders. We examined if the likelihood of AD was higher when biomarker levels deviated more from normal levels. For this purpose, we constructed interval‐specific likelihood ratios (LRs) for CSF biomarkers amyloid Aβ1‐42, total Tau protein (tTau) and hyperphosphorylated Tau protein (pTau181).MethodThis retrospective single center study included 208 patients who 1) attended the Neurology Memory Clinic of the University Hospital Leuven in the period of September 2011 till July 2017, 2) underwent CSF AD biomarkers assessment in the diagnostic workup (Innotest, Fujirebio) and 3) had a stable clinical diagnosis for at least three years after diagnosis. For each biomarker, we calculated LRs for AD for different test result intervals, based on 2 methods, including intervals with boundaries equal to limited multiples of previously published cutoff values (method 1), or to generate intervals well distributed over the entire dynamic range of biomarker levels (method 2). In a graphical representation, post‐test probability of AD was related to pre‐test probability and test result interval for each biomarker.ResultBoth methods for constructing intervals showed that for any of the biomarkers the LR increased significantly once deviating from normal values. Further dividing these aberrant levels into additional intervals (method 2) further increased the LR. Further dividing normal levels into more intervals did further decrease the LR, except for Aβ1‐42. No LRs &gt; 10 or &lt; 0.1, suggesting clinically meaningful differences between pre‐test and post‐test probability, were encountered. LRs between 0.1 – 0.2 or 5 – 10, suggestive of modest clinical differences, were seen for normal Aβ1‐42 levels (800 – 1,000 pg/mL; LR = 0.168), and aberrant tTau levels (≥ 1,000 pg/mL; LR = 5.540) and pTau181 levels (≥ 80 pg/mL; LR between 5.936 and 7.420).ConclusionThe likelihood of AD changed as CSF levels of AD biomarkers deviated more outspoken from normal range, yet related to a modest clinical significance given the partial overlap between AD and non‐AD of biomarker values that deviated from normal values.

A benchmark study on the model-based estimation of the go-kart side-slip angle

Nowadays, the active safety systems that control the dynamics of passenger cars usually rely on real-time monitoring of vehicle side-slip angle (VSA). The VSA can’t be measured directly on the production vehicles since it requires the employment of high-end and expensive instrumentation. To realiably overcome the VSA estimation problem, different model-based techniques can be adopted. The aim of this work is to compare the performance of different model-based state estimators, evaluating both the estimation accuracy and the computational cost, required by each algorithm. To this purpose Extended Kalman Filters, Unscented Kalman Filters and Particle Filters have been implemented for the vehicle system under analysis. The physical representation of the process is represented by a single-track vehicle model adopting a simplified Pacejka tyre model. The results numerical results are then compared to the experimental data acquired within a specifically designed testing campaign, able to explore the entire vehicle dynamic range. To this aim an electric go-kart has been employed as a vehicle, equipped with steering wheel encoder, wheels angular speed encoder and IMU, while an S-motion has been adopted for the measurement of the experimental VSA quantity.

Analysis of Inductor Peak Current Based on the Quadratic Buck-Boost Converter with Switched Inductor Network in the Entire Dynamic Range

According to the working principle of the proposed quadratic Buck-Boost Converter with Switched Inductor Network, the converter is divided into continuous conduction mode (CCM) and discontinuous conduction mode (DCM) according to whether the minimum current flowing through the inductor L3 is equal to zero. Subsequently, the inductor peak current in the two modes are derived. Based on the quadratic Buck-Boost Converters with Switched Inductor Network, a entire dynamic range inductor peak current analysis method is proposed within a given input voltage and load range. Meanwhile, In terms of different value ranges of the inductor L3, the working area of the converter is divided into three parts, and the maximum inductor peak current in the three working conditions are compared. By analyzing the relationship between the maximum inductor peak current and the value of the inductor L3, it is concluded that L3 = L3CA is the critical inductance at which the maximum inductor peak current of the converter reaches the minimum in the entire dynamic range. Finally, the experimental results demonstrate the reasonability and correctness of the proposed theoretical analysis.

Comparison of SARS-CoV-2 N gene real-time RT-PCR targets and commercially available mastermixes

BackgroundThis study aimed to evaluate the impact of four different reverse transcription quantitative PCR (RT-qPCR) master mixes on the performance of SARS-CoV-2 diagnostic PCRs using three primer/probe assays targeting the N gene (A, B and C). The dynamic range and lowest detected quantity was determined using a SARS-CoV-2 partial N gene RNA transcript dilution series (100,000–1 copy/μl) and verified using 72 nose and throat swabs, 29 of which tested positive for SARS-CoV-2 RNA. ResultsAssay C consistently detected the lowest quantity of partial N gene RNA transcript with all mastermixes. The Takara One Step PrimeScript™ III RT-PCR Kit mastermix enabled all primer pairs to detect the entire dynamic range evaluated, with the Qiagen Quantifast and Thermofisher TaqPath 1-Step kits also performing well.Sequences from all three primer/probe sets tested in this study (assay A, B and C) have 100 % homology to ≥97 % of the of SARS-CoV-2 sequences available up to 31st December 2020 (n = 291,483 sequences). ConclusionsThis work demonstrates that specific assays (in this case assay C) can perform well in terms of dynamic range and lowest detected quantity regardless of the mastermix used. However we also show that, by choosing the most appropriate mastermix, poorer performing primer pairs are also able to detect all of the template dilutions investigated. This work increases the potential options when choosing assays for SARS-CoV-2 diagnosis and provides solutions to enable them to work with optimal analytical sensitivity.

Nonlinear Implementable Control of a Dual Active Bridge Series Resonant Converter

This article presents a novel control strategy for a dual active bridge series resonant converter. The strategy seeks to ensure the stability of the converter over its entire dynamic range while enhances the transient response. Both properties allow the use of the converter in new applications, where fast dynamics are required, surpassing the performance of existing feedback loops. Starting from the generalized averaged model of the converter, we propose a nonlinear control strategy by means of Lyapunov's stability theory. After that, we derive a series of modifications in order to implement the strategy in a microcontroller or a DSP, including a sensorless method to tackle the lack of measurements of certain variables and an adaptive control law to deal with uncertain parameters in the model. The strategy is evaluated in simulations and experiments, employing a commercial converter, and comparing the results with other control policies.

Dynamic-range extension of MAES multichannel analyzers based on BLPP-2000 and BLPP 4000 photodetector arrays

One trend in the development of integral atomic emission spectral analysis with low spectral background excitation sources, such as inductively coupled or microwave plasma, is to increase the dynamic range of spectrum recording systems based on photodetector arrays. To achieve low detection limits, it is necessary to use photodetector arrays with low reading noise. The dynamic range of a single readout of such photodetector arrays usually does not exceed four orders of magnitude. The dynamic range increase due to the accumulation of spectra from multiple acquisition leads to a quadratic increase in the measurement time. This method does not allow one to cover the entire dynamic range of spectral line intensities of inductively coupled or microwave plasma (which can reach seven orders of magnitude) while maintaining an acceptable total measurement time of a sample spectrum. As an alternative, it is proposed to increase the dynamic range toward higher line intensities by using two different alternating accumulation times during measurement. The objective of this study is to implement the proposed recording mode in MAES analyzers based on BLPP-2000 and BLPP-4000 photodetector arrays in order to increase the dynamic range of recorded spectral lines. Dependences of the signal-to-noise ratio and the dynamic range of spectral lines recorded in integral atomic emission spectrometry on the accumulation time, the total measurement time, the spectral background level, and the photodetector array parameters are obtained. It is shown theoretically that the use of the recording mode with alternating different accumulation times should increase the dynamic range of BLPP-2000 and BLPP-4000 photodetector arrays by two orders of magnitude. The dynamic range of spectral line intensities of a hollow-cathode lamp is shown experimentally to increase by two orders of magnitude (to five orders of magnitude).

Method and unit for dynamic control of conversion characteristics of spectrometric paths for multichannel charged particle registration systems

A method and unit for dynamic control of conversion characteristics of spectrometric paths of multichannel charged particle registration systems based on specialized microchip with a large degree of integration similar to IDE1140 in structure is proposed. The conversion characteristics are controlled during operation of the device by auto-adjusting the offset and gain of the scaling amplifier. The proposed method allows to use the entire dynamic range of the analog-to-digital converter and adjust the temperature drift for each channel at the hardware level during operation of the device.

Non Subsampled Shearlet Transform Based Fusion of Multiple Exposure Images

Fusion of multiple exposure images has attracted attention over the past decade and several algorithms have been developed, so as to capture the entire dynamic range of the scene in a single image. Capturing images with changes in exposure settings leads to a set of multiple exposure images with different areas of the scene highlighted in different image. Weak edges and fine textures of the image are lost during an under or over exposure. Also for objective evaluation we need to measure and both the structural and textural information in the images simultaneously. To address this issue an algorithm based on the Non-subsampled shearlet transform (NSST) for fusing multiple exposure images is proposed so as to depict clearly the dimly lit, brightly lit and well lit regions in a single fused image. In the proposed algorithm NSST decomposition is first performed on the images to obtain the multi-scale and multi-direction representations. The high frequency bands are fused by retaining the pixels with the highest value coefficients at each sub band at each level. Whereas the low frequency bands are fused by averaging operation. Proposed method leads to better results in visual quality.