Signal Readout System Research Articles

Ratiometric upconversion-luminescence in-situ sampling aptasensing platform integrated with smartphone-based device for visual detection of 17β-estradiol

Rapid initial screening of health markers and food hazards are crucial indicators for ensuring human well-being. Hence, an upconversion-luminescence based aptasensing platform for the in-situ sampling of hazards has been proposed with portable equipment for point-of-care testing (POCT). The aptasensing platform consists of a polymethylmethacrylate needle and a paper-based microfluidic strip patterned with a sacrificial valve, paraffin barriers, and three independent detection zones. The detection zones were assembled with a luminescence resonance energy transfer system constructed by the core/shell/shell structure of upconversion nanoparticles (UCNPs) as the donor, SYBR Green Ⅰ as the acceptor with an aptamer bridge. The biosensing platform has been extended for 17β-estradiol to validate its feasibility in a dual-mode signal readout system based on smartphone imaging and spectrometer. Under the optimal conditions, good linear relationships were achieved based on images (0.05–200 ng/mL) and ratiometric spectra (0.02–200 ng/mL), respectively. Thus, the biosensing platform with portable equipment might provide an economic and viable route for POCT.

Development of a Nondestructive Moldy Coffee Beans Detection System Based on Electronic Nose

Coffee drinks prepared from moldy coffee beans can adversely affect human health. No convenient screening method for detecting the smell of stale coffee beans exists. Accordingly, this study developed an electronic nose (E-nose) system for detecting the smell of coffee beans. This system comprises an environmental control system, a sensor array, and a data signal readout system. The system can distinguish various degrees of mold on coffee beans through the recognition of the smell of the coffee beans. In this study, we established a standard operating procedure to collect gas samples from coffee beans in a temperature- and humidity-controlled environment and recorded changes in the signals by using the sensor array after introducing the target gas. Features were first extracted from the collected data, then dimensionality reduction methods such as principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to these features. Thus, their complexity was reduced, and the noise was eliminated. K-nearest neighbor (KNN) and support vector machine (SVM) were adopted as classification algorithms, and the classification accuracy of the proposed system reached 91.77%.

PEC/Colorimetric Dual-Mode Lab-on-Paper Device via BiVO4/FeOOH Nanocomposite In Situ Modification on Paper Fibers for Sensitive CEA Detection.

A dual-mode lab-on-paper device based on BiVO4/FeOOH nanocomposites as an efficient generating photoelectrochemical (PEC)/colorimetric signal reporter has been successfully constructed by integration of the lab-on-paper sensing platform and PEC/colorimetric detection technologies for sensitive detection of carcinoembryonic antigen (CEA). Concretely, the BiVO4/FeOOH nanocomposites were in situ synthesized onto the paper-working electrode (PWE) through hydrothermal synthesis of the BiVO4 layer on cellulose fibers (paper-based BiVO4) which were initially modified by Au nanoparticles for improving the conductivity of three dimensional PWE, and then the photo-electrodeposition of FeOOH onto the paper-based BiVO4 to construct the paper-based BiVO4/FeOOH for the portable dual-mode lab-on-paper device. The obtained nanocomposites with an FeOOH needle-like structure deposited on the BiVO4 layer exhibits enhanced PEC response activity due to its effective separation of the electron-hole pair which could further accelerate the PEC conversion efficiency during the sensing process. With the introduction of CEA targets onto the surface of nanocomposite-modified PWE assisted by the interaction with the CEA antibody from a specific recognition property, a signal-off PEC signal state with a remarkable photocurrent response decreasing trend can be achieved, realizing the quantitative detection of CEA with the PEC signal readout mode. By means of a smart origami paper folding, the colorimetric signal readout is achieved by catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) to generate blue oxidized TMB in the presence of H2O2 due to the satisfied enzyme-like catalytic activity of the needle-like structure, FeOOH, thereby achieving the dual-mode signal readout system for the proposed lab-on-paper device. Under the optimal conditions, the PEC and colorimetric signals measurement were effectively carried out, and the corresponding linear ranges were 0.001-200 ng·mL-1 and 0.5-100 ng·mL-1 separately, with the limit of detection of 0.0008 and 0.013 ng·mL-1 for each dual-mode. The prepared lab-on-paper device also presented a successful application in serum samples for the detection of CEA, providing a potential pathway for the sensitive detection of target biomarkers in clinical application.

Designing of a high-performance fluorescent small molecule enables dual-mode and ultra-sensitive fluorescence visualizing of HSO3− and HClO in dried fruit, beverage, and water samples

Herein, a novel hemicyanine derivative (E)-3-(1,1-dimethyl-2-(4-(methylthio)styryl)-1H-benzo[e]indol-3-ium-3-yl)propane-1-sulfonate (BIS) has been reasonably designed. Compound BIS is long-wavelength emissive and water-soluble with a large Stokes shift. Intriguingly, probe BIS provides a dual-mode fluorescence response pattern for the sensing of bisulfite (HSO3−) and hypochlorous acid (HClO) with great limit of detections (3.6 and 57.4 nM). First, the 1,4-Michael addition of HSO3− on the conjugated double bond triggers a ratiometric response (I465/I575). Second, the rapid oxidation of HClO on the thioether moiety provides a turn-on response (I575). Evaluation of HSO3− and HClO levels in dried fruit, beverage, and water samples has been carried out with satisfactory results. Moreover, motivated by an impressive chromatic variation (red to blue), smartphone-assisted signal readout system and thin-film sensing platform are facilely constructed for real-time and on-site measurement of HSO3− levels. Furthermore, probe BIS is used for the in vivo imaging of HSO3− in edible fish models.

Radioluminescence Response of Ce-, Cu-, and Gd-Doped Silica Glasses for Dosimetry of Pulsed Electron Beams.

Radiation-induced emission of doped sol-gel silica glass samples was investigated under a pulsed 20-MeV electron beam. The studied samples were drawn rods doped with cerium, copper, or gadolinium ions, which were connected to multimode pure-silica core fibers to transport the induced luminescence from the irradiation area to a signal readout system. The luminescence pulses in the samples induced by the electron bunches were studied as a function of deposited dose per electron bunch. All the investigated samples were found to have a linear response in terms of luminescence as a function of electron bunch sizes between Gy/bunch and Gy/bunch. The presented results show that these types of doped silica rods can be used for monitoring a pulsed electron beam, as well as to evaluate the dose deposited by the individual electron bunches. The electron accelerator used in the experiment was a medical type used for radiation therapy treatments, and these silica rod samples show high potential for dosimetry in radiotherapy contexts.

Research on weak signal readout systems for neutrinoless double-beta decay experiments based on bolometers

This paper develops a prototype signal readout system based on the physical mechanism and signal-to-noise ratio of the ultralow voltage signal characteristics of a bolometer. The preamplifier module is one of the key difficulties of the prototype: the internal resistance is as high as one hundred MΩ, the signal frequency band is susceptible to low-frequency noise, and the high energy resolution requires a high signal-to-noise ratio that is matching the input impedance to design a preamplifier with a good common-mode rejection ratio and low inherent noise. Therefore, the preamplifier circuit is designed with an instrument amplifier. At present, the energy resolution of the bolometer is 500 ~ 1000 nV (root mean square, rms) at the input of the signal readout system. According to the calculation, the theoretical value of the inherent noise at the input end is 394 nVrms, including a theoretical value for the equivalent input voltage noise of 166 nVrms, while the actual measurement value is less than 180 nVrms, which is basically consistent with the theoretical value. In addition, the signal gain (10,000) and frequency response of the prototype are experimentally verified. The experimental results show that the gain is 9400, and the frequency and waveform are not distorted within the allowable error range; all of these parameters meet the design requirement.

Energy resolution and linearity of XENON1T in the MeV energy range

Xenon dual-phase time projection chambers designed to search for weakly interacting massive particles have so far shown a relative energy resolution which degrades with energy above sim 200 keV due to the saturation effects. This has limited their sensitivity in the search for rare events like the neutrinoless double-beta decay of ^{136} hbox {Xe} at its Q value, Q_{beta beta }simeq 2.46,hbox {MeV}. For the XENON1T dual-phase time projection chamber, we demonstrate that the relative energy resolution at 1,sigma /mu is as low as (0.80 pm 0.02) % in its one-ton fiducial mass, and for single-site interactions at Q_{beta beta }. We also present a new signal correction method to rectify the saturation effects of the signal readout system, resulting in more accurate position reconstruction and indirectly improving the energy resolution. The very good result achieved in XENON1T opens up new windows for the xenon dual-phase dark matter detectors to simultaneously search for other rare events.

Design and performance of the front-end electronics for a 10BF3 tube array

A neutron yield monitoring system based on a 10BF3 tube array was designed to monitor fast neutrons with an energy of 14 MeV and a yield of 104–108 produced by a deuterium-tritium fusion reaction. The array contained six 10BF3 tubes of different sizes. The signal readout system used a charge sensitive preamplifier (CSA) as the front-end circuit. The CSA was optimized and tested to ensure that it met the measurement requirements for low charge and high counting rate. The zero-capacitance equivalent noise charge (ENC) was 2425 e− and the ENC slope was 15 e−/pF. In the temperature range 0–60̂C, the ENC slope was 10 e−/̂C and the baseline drift was less than 0.05 mV/̂C. In the 10 h long-term stability test, the baseline drift was less than 0.07 mV.

Development of signal readout system for the realization of a flexible multipoint blood flow monitoring device

Development of signal readout system for the realization of a flexible multipoint blood flow monitoring device

ディレイライン検出器を用いた投影型イメージング質量分析における有効な信号処理技術の開発

Simultaneously detecting arrival times and two-dimensional (2D) positions of individual ions is essential for imaging mass spectrometry (imaging MS) in the microscope (stigmatic) mode which is superior in terms of spatial resolution to the more commonly used microprobe mode imaging MS. A detection system for microscope mode imaging MS was developed using an in-house constructed laser desorption/ionization (LDI) linear time-of-flight mass spectrometer as a platform for use and a delay line detector (DLD) was used as the position-sensitive ion detector. A signal readout system for DLD was configured using high-speed analog-to-digital converter (ADC) modules to detect multiple m/z-resolved ions. An efficient acquisition/processing technique for the data, which was acquired using an ADC-based system was developed to achieve an increased permissible laser pulse repetition rate, reduced data size and real time data processing. Multiple stigmatic images of m/z-resolved ions were obtained from a model sample formed of micro-dots of three types of dyes without using an ion gate for m/z selection. The measurement time was 18 minutes at an ionizing laser pulse repetition rate of 10 Hz, and the size of the data, which was comprised of lists of flight times and 2D positions of individual detected ions in ASCII format, was below 5 MB. The ability of LDI microscope mode imaging MS to obtain a complete series of m/z-resolved snapshots of LDI-generated ions in a single measurement was demonstrated. The present approach provides a realistic solution that can make use of a high-speed ADC for the DLD signal readout, and may facilitate further technical developments of microscope mode imaging MS.

Signal-Readout System for Optical Pickup with Homodyne Detection Scheme

We developed a signal-readout system suitable for optical pickups with a homodyne detection scheme, which is used to amplify signal lights using optical interference. The system consists of an optical-signal detection circuit and a readout-signal generator. The optical-signal detection circuit, which contains pairs of photodiodes connected in series, successfully cancels out large DC components arising from a reference light. This made it possible to avoid the output signal saturation of current-to-voltage amplifiers and raise the upper limit of signal gain. The readout-signal generator generates a readout signal on the basis of the phase-diversity method, which stabilizes readout signal amplitude. By using this system, a signal gain of 3.6 was obtained on a commercially available disc.

Development of a Digital Signal Readout System for Large TES Arrays

We are developing a digital signal readout system for arrays of high-resolution gamma and fast-neutron detectors based on superconducting transition edge sensors (TESs). The readout system allows for real time data acquisition and analysis at count rates exceeding 100 Hz for pulses with several ∼ms decay times with minimal loss of energy resolution compared to optimum filtering. This digital signal processing system had originally been developed for gamma-ray analysis with HPGe detectors, and we have modified the hardware and firmware to accommodate the slower TES signals. Parameters of the filtering algorithm have been optimized to maximize either resolution or throughput. Here we present a summary of the digital signal processing hardware and discuss its initial performance.

MONITORING AND ADAPTIVE REMOVAL OF THE POWER SUPPLY HARMONICS APPLIED TO THE VIRGO READ-OUT NOISE

The VIRGO signal read-out system is based on a sixteen channels architecture. The system is now installed at the site and the noise of eight of the channels has been measured. The noise at 50 Hz and all its harmonics is coherent with a simultaneous measurement of the power supply. The power supply measurement has been used to remove the 50 Hz line and all its harmonics from the signal read-out noise.

Noncontacting microwave coupling to a cryogenic gravitational radiation antenna

Gravitational radiation detectors must detect extremely small displacements, and thus require elaborate vibration isolation systems to attenuate the surrounding environmental noise. Contacting electrical leads can provide a direct path that will short circuit the vibration isolation, and degrade the antenna Q factor. Noncontacting microstrip transceivers provide a practical means of electromagnetically coupling to a resonant bar gravitational antenna when a microwave transducer is used as a signal readout system. Two microwave patch antennas now operate as transceivers on the University of Western Australia’s 1.5 tonne niobium bar gravitational radiation antenna and are described in detail in this paper. This system allows improved vibration isolation without degradation of the acoustic Q factor of the niobium bar. Combined with a cryogenic amplifier, this system should achieve a reduction of 57 dB in the series noise power. This corresponds to a factor of 700 reduction in the effective displacement noise when referred to the transducer, from 2×10−16 to 3×10−19 m/√Hz.