Fast Data Acquisition Research Articles

Automated dual two-dimensional liquid chromatography approach for fast acquisition of three-dimensional data using combinations of zwitterionic polymethacrylate and silica-based monolithic columns

A monolithic sulfobetaine polymethacrylate micro-column BIGDMA-MEDSA designed in our laboratory, shows dual retention mechanism: In acetonitrile-rich mobile phase, hydrophilic interactions control the retention (HILIC system), whereas in more aqueous mobile phases the column shows essentially reversed-phase behavior with major role of hydrophobic interactions. The zwitterionic polymethacrylate micro-column can be used in the first dimension of two-dimensional LC in alternating reversed-phase (RP) and HILIC modes, coupled with an alkyl-bonded core-shell or silica-based monolithic column in the second dimension, for HILIC×RP and RP×RP comprehensive two-dimensional separations. During the HILIC×RP period, a gradient of decreasing acetonitrile gradient is used for separation in the first dimension, so that at the end of the gradient the polymeric monolithic micro-column is equilibrated with a highly aqueous mobile phase and is ready for repeated sample injection, this time for separation under reversed-phase gradient conditions with increasing concentration of acetonitrile in the first dimension. The fast repeating reversed-phase gradients on a short silica-monolithic or core-shell column in the second dimension can be optimized independently of the actual running first-dimension gradient program. As the alternating HILIC and RP separations on the first-dimension zwitterionic methacrylate column are based on complementary retention mechanisms, the instrumental setup essentially represents two coupled two-dimensional systems. It is first time that such an automated dual LCxLC approach is reported. The novel system allows obtaining three-dimensional data in a relatively short time and can be applied not only to multidimensional gradient separations of flavones and related polyphenolic compounds.

Advances in Mid-Infrared Spectroscopy for Chemical Analysis.

Infrared spectroscopy in the 3-20 μm spectral window has evolved from a routine laboratory technique into a state-of-the-art spectroscopy and sensing tool by benefitting from recent progress in increasingly sophisticated spectra acquisition techniques and advanced materials for generating, guiding, and detecting mid-infrared (MIR) radiation. Today, MIR spectroscopy provides molecular information with trace to ultratrace sensitivity, fast data acquisition rates, and high spectral resolution catering to demanding applications in bioanalytics, for example, and to improved routine analysis. In addition to advances in miniaturized device technology without sacrificing analytical performance, selected innovative applications for MIR spectroscopy ranging from process analysis to biotechnology and medical diagnostics are highlighted in this review.

Quantification of the vocal folds’ dynamic displacements

Fast dynamic data acquisition techniques are required to investigate the motional behavior of the vocal folds (VFs) when they are subjected to a steady air-flow through the trachea. High-speed digital holographic interferometry (DHI) is a non-invasive full-field-of-view technique that has proved its usefulness to study rapid and non-repetitive object movements. Hence it is an ideal technique used here to measure VF displacements and vibration patterns at 2000 fps. Analyses from a set of 200 displacement images showed that VFs’ vibration cycles are established along their width (y) and length (x). Furthermore, the maximum deformation for the right and left VFs’ area may be quantified from these images, which in itself represents an important result in the characterization of this structure. At a controlled air pressure, VF displacements fall within the range ~100–1740 nm, with a calculated precision and accuracy that yields a variation coefficient of 1.91%. High-speed acquisition of full-field images of VFs and their displacement quantification are on their own significant data in the study of their functional and physiological behavior since voice quality and production depend on how they vibrate, i.e. their displacement amplitude and frequency. Additionally, the use of high speed DHI avoids prolonged examinations and represents a significant scientific and technological alternative contribution in advancing the knowledge and working mechanisms of these tissues.

Building Zone Regulation Compliance Using LIDAR Data: Real-Life Tests in İstanbul

Airborne Laser scanning systems with light detection and ranging (LIDAR) technology is one of the fast and accurate 3D point data acquisition techniques. Generating accurate digital terrain and/or surface models (DTM/DSM) is the main application of collecting LIDAR range data. The LIDAR technique facilitates the rapid production of models which contain ground and above surface objects in 3D (Jaafar et al., 1999). Today automatic / semi-automatic generation of 3D digital building models and other city furniture from LIDAR data is a very active area of scientific research (Elaksher and Bethel, 2002) indicates that manual surface reconstruction is very costly and time consuming, and the development of automated algorithms is of great importance. Currently with this LIDAR data in place, it is possible to derive models and information (e.g. the heights of the buildings).This paper focuses on and explains our efforts on automatically checking Buildings’ Zoning Regulation Compliance by integrating geometric information derived from 3D LIDAR data and semantic information acquired from 2D Implementation Development Maps

Frost Layer Growth Based on High-Resolution Image Analysis

We report the results of experiments using high-resolution imaging and digital analysis of transient frost growth to obtain quantitative information on frost thickness. The measurement technique provides faster data acquisition and much higher accuracy than traditional approaches. An empirical model of frost growth that captures the fast and slow growth periods is developed based on this data. The key physical and correlating parameter is the ratio of sensible heat transfer-to-total heat transfer, and the growth rate varies inversely with this ratio. The resulting correlation faithfully captures measured growth rates across a wide spectrum of frosting conditions and gives better predictive capability than that of existing correlations. The present model eliminates the need for specifics of the experimental apparatus and test surface as factors in prediction, as well as the necessity of measuring the frost–air interface temperature.

Improved Cardiac Proton Magnetic Resonance Spectroscopy at 3 T Using High Permittivity Pads.

The aim of this study was to determine whether high permittivity (HP) pads can be used to increase the signal-to-noise ratio (SNR) of cardiac proton magnetic resonance spectroscopy at 3 T, allowing faster data acquisition. The institutional review board approved the study protocol, and written informed consent was obtained from all participants. In 22 healthy volunteers, water-suppressed localized spectra were acquired in the interventricular septum without and with HP pads. The SNR and myocardial triglyceride content (MTGC) were measured without and with the HP pads, and the results were compared with a paired sample Student t test. Application of HP pads increased mean (SD) SNR from 27.9 (15.6) to 42.3 (24.4) (P < 0.0001), a mean gain of 60%. The acquisition time can thereby be reduced from just under 5 minutes to just under 2 minutes while maintaining the same SNR. The mean (SD) MTGC was 0.39% (0.17%) without pads and 0.38% (0.15%) with pads (P = 0.83) for the healthy volunteers, showing that no bias is introduced by using the pads. No difference in spectral linewidth was measured (P = 0.80), the values being 17.4 (4.9) Hz without and 17.1 (3.2) Hz with pads. Both transmit and receive maps showed increases in sensitivity due to the presence of the HP pads. High permittivity pads improve cardiac proton magnetic resonance spectroscopy at 3 T by increasing the SNR on average by 60%, which can be used to reduce data acquisition time significantly, allowing fast assessment of MTGC without compromising spectral quality. The SNR increase arises primarily from the increase in receive sensitivity of the phased array, which is more closely coupled to the body via the HP pads. In addition, the transmit efficiency is also increased, allowing shorter or lower power radiofrequency pulses.

Interview

Professor Dosik Hwang, from Yonsei University in Korea, talks about the work behind the paper ‘Murmur-adaptive compression technique for phonocardiogram signals’, page 183. Professor Dosik Hwang Our field of research is focused on 1) biomedical signal processing, such as electro-/phono- cardiograms; and 2) tomographic imaging, such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound (US). Our mission is to help human health by developing practical algorithms for processing human vital signals and by advancing novel medical imaging technologies. Examples include noise removal in electrocardiograms (ECG) and phonocardiograms (PCG), unifying frameworks of ECG and PCG, robust feature extractions of ECG/PCG, denoising of MR images, multi-contrast MRIs, fast acquisition of MRI data and reconstruction, susceptibility-weighted MR imaging, brain tomographic imaging, artefact corrections in CT, and motion analysis in US. The initial vision of making contributions to humans led me to keep pursuing this field of research. Mobile monitoring of human vital signals – as mobile and wearable devices evolve, health technologies are being actively incorporated into these devices enabling the constant monitoring of human vital signals and subsequent diagnosis based on it. However, the application of conventional health technologies into mobile devices needs rigorous signal processing techniques, since the data acquisitions are less optimal than those of the conventional standard devices in regular hospitals. Special techniques for denoising, robust feature extraction, data compression, and novel multi-modal signal processing will expedite the successful applications of the current health technologies into the mobile world. I am also interested in multi-contrast medical imaging. As the current medical imaging systems are advanced to produce multiple contrast images, novel techniques to handle these multiple datasets need to be developed with new insights for better image quality, better diagnostic outcome, and better imaging efficiency. We are actively involved in these special applications. We have reported an effective way of compression for the phonocardiogram signals (PCG) emphasising their diagnostic purpose. In the several previous attempts to compress PCG, their main interest of compression was to reduce the data size while maintaining a certain level of overall sound quality without considering a diagnostic purpose. The natural consequence of it was to lose some of valuable diagnostic information when compressed. As an example of this study, the murmur (noise-like abnormal heart sound) information in PCG is diagnostically important, but conventional compression techniques would treat some of this murmur sound as noise, and distort it during compression. We had successfully incorporated a murmur estimate process during the compression and were able to adaptively compress PCG without significant loss of the murmur information in the compressed PCG. The effectiveness of this technique was validated in quantitative metrics and in subjective quality assessment as well. Two main challenges were 1) effective incorporation of the murmur estimate process into the overall compression procedure, and 2) evaluation of the compressed PCG. In order to seamlessly incorporate the murmur estimate in the compression, we developed a murmur estimate technique on the several levels of wavelet decomposition and combined it with the wavelet compression technique, which resulted in the murmur-adaptive compression performance. The conventional evaluation method for compressed sounds was not effective to evaluate the murmur-containing PCGs. In order to evaluate the quality of the murmur-related sound in the compressed PCG, we adopted both the quantitative metrics such as the compression ratio (CR) and the percent root-mean-square difference (PRD) and a subjective assessment method, MUSHRA (multi-stimulus test with hidden reference and anchor). We are working on how to combine multi-modal vital signals acquired at the same time in terms of signal acquisition, noise removal, feature extraction, signal enhancement, and diagnosis. In addition, we are also actively working on multi-contrast and multi-modal medical imagings, which will be eventually combined with the vital signals for thorough analysis and guidance for health. This field of research will help accumulate massive diagnostic information on a specific person and the general population as well, which will significantly contribute to accurate diagnosis, effective monitoring of health, and guiding personal health life. The exciting challenges would be how to incorporate multi-modal vital signals to fulfil these purposes.

Depletion with Cyclodextrin Reveals Two Populations of Cholesterol in Model Lipid Membranes

Recent results provide evidence that cholesterol is highly accessible for removal from both cell and model membranes above a threshold concentration that varies with membrane composition. Here we measured the rate at which methyl-β-cyclodextrin depletes cholesterol from a supported lipid bilayer as a function of cholesterol mole fraction. We formed supported bilayers from two-component mixtures of cholesterol and a PC (phosphatidylcholine) lipid, and we directly visualized the rate of decrease in area of the bilayers with fluorescence microscopy. Our technique yields the accessibility of cholesterol over a wide range of concentrations (30–66 mol %) for many individual bilayers, enabling fast acquisition of replicate data. We found that the bilayers contain two populations of cholesterol, one with low surface accessibility and the other with high accessibility. A larger fraction of the total membrane cholesterol appears in the more accessible population when the acyl chains of the PC-lipid tails are more unsaturated. Our findings are most consistent with the predictions of the condensed-complex and cholesterol bilayer domain models of cholesterol-phospholipid interactions in lipid membranes.

The Giga Bit Transceiver based Expandable Front-End (GEFE)—a new radiation tolerant acquisition system for beam instrumentation

The Giga Bit Transceiver based Expandable Front-End (GEFE) is a multi-purpose FPGA-based radiation tolerant card. It is foreseen to be the new standard FMC carrier for digital front-end applications in the CERN BE-BI group. Its intended use ranges from fast data acquisition systems to slow control installed close to the beamlines, in a radioactive environment exposed to total ionizing doses of up to 750 Gy. This paper introduces the architecture of the GEFE, its features as well as examples of its application in different setups.

Compressive Sampling Photoacoustic Microscope System based on Low Rank Matrix Completion

Abstract Photoacoustic Microscopy (PAM) has developed into a powerful tool for deep tissue imaging with a better spatial resolution. But the data acquisition time in PAM is so long that it is a great challenge for real time imaging. In this paper, a new PAM data acquisition and image recovery method, called Compressive Sampling PAM System based on Low Rank Matrix Completion (CSLRM-PAM) is proposed to obtain a high-resolution PAM image with relatively low sampling rates. In order to successfully set up a CSLRM-PAM system, the two key problems which we need to keep focus on are design of the compressive sampling scheme and the corresponding image recovery algorithm. In this paper, two compressive sampling schemes based on expander graphs are proposed to replace the conventional point-by-point scanning scheme to implement fast data acquisition. Then, the low rank matrix completion is utilized to obtain high-resolution PAM image directly from the compressive sampling data. The effectiveness of the proposed scheme is validated using both numerical analysis and PAM experiments. In contrast with the conventional system, the proposed CSLRM-PAM system is able to dramatically decrease the total sampling points for a relatively high-resolution PAM image and to implement accelerated data acquisition.

A Fast Optical Spectrum Data Acquisition Method Based on FPGA and DSP

Abstract This paper presents a fast CCD optical spectrum data acquisition method based on FPGA, FIFO and DSP. Introduces a linear CCD timing sequence control signal generation and high speed ADC interface with FIFO and DSP in detail, publishes this design key parts FPGA logic schematic and VHDL source code, provides a general solution for universal high speed CCD optical spectrum data acquisition and analysis system.

Sparse photoacoustic microscopy based on low-rank matrix approximation

As a high-resulotion biological imaging technology, photoacoustic microscopy (PAM) is difficult to use in real-time imaging due to the long data acquisition time. Herein, a fast data acquisition and image recovery method named sparse PAM based on a low-rank matrix approximation is proposed. Specifically, the process to recover the final image from incomplete data is formulated into a low-rank matrix completion framework, and the “Go Decomposition” algorithm is utilized to solve the problem. Finally, both simulated and real PAM experiments are conducted to verify the performance of the proposed method and demonstrate clinical potential for many biological diseases.

Indirect determination of soil water content

This manuscript reviews the recent developments in indirect methods used to measure soil watent content (SWC). It focuses on three types of methodological approaches: (i) high-frequency electromagnetic methodologies (dielectric methods and Ground Penetrating Radar), (ii) low-frequency electromagnetic methods (resistivity method and spectral induced polarization-SIP) and (iii) emerging methods (laboratory and ground-based nuclear magnetic resonance-NMR techniques and methods based on fiber optic temperature sensing systems). For each method the physical principles and the corresponding methodology are briefly described first, followed by the recent methodological advances. These recent advances address the following issues: (a) integration of different types of sensors to design new multi-functional devices, (b) miniaturization of low-cost and easily-installed electromagnetic sensors, (c) fusion and assimilation of data acquired from multiple modalities with different sampling rates and spatial resolutions, (d) physical understanding of spectra and distributed parameters measured by SIP and NMR methods, (e) improvement of geophysical inversion techniques combined with fast data acquisitions (4D monitoring of SWC).

Capabilities of fast data acquisition with microsecond time resolution in inductively coupled plasma mass spectrometry and identification of signal artifacts from millisecond dwell times during detection of single gold nanoparticles

In this paper, a home-built DAQ featuring microsecond time resolution is used to demonstrate advantages of fast data acquisition and to uncover potential artifacts in single-particle ICP-MS.

Miniaturized ultra-high performance liquid chromatography coupled to electrochemical detection: Investigation of system performance for neurochemical analysis

The interest in implementation of miniaturized ultra-high performance liquid chromatography (UHPLC) in neurochemical research is growing because of the need for faster, more selective and more sensitive neurotransmitter analyses. The instrument performance of a tailor designed microbore UHPLC system coupled to electrochemical detection (ECD) is investigated, focusing on the quantitative monoamine determination in in vivo microdialysis samples. The use of a microbore column (1.0mm I.D.) requires miniaturization of the entire instrument, though a balance between extra-column band broadening and injection volume must be considered. This is accomplished through the user defined Performance Optimizing Injection Sequence, whereby 5μL sample is injected on the column with a measured extra-column variance of 4.5–9.0μL2 and only 7μL sample uptake. Different sub-2μm and superficially porous particle stationary phases are compared by means of the kinetic plot approach. Peak efficiencies of about 16000–35000 theoretical plates are obtained for the Acquity UPLC BEH C18 column within 13min analysis time. Furthermore, the coupling to ECD is shown suitable for microbore UHPLC analysis thanks to the miniaturized flow cell design, sufficiently fast data acquisition and mathematical data filtering. Ultimately, injection of in vivo samples demonstrates the applicability of the system for microdialysis analysis.

A new technique to characterize CT scanner bow‐tie filter attenuation and applications in human cadaver dosimetry simulations

To present a noninvasive technique for directly measuring the CT bow-tie filter attenuation with a linear array x-ray detector. A scintillator based x-ray detector of 384 pixels, 307 mm active length, and fast data acquisition (model X-Scan 0.8c4-307, Detection Technology, FI-91100 Ii, Finland) was used to simultaneously detect radiation levels across a scan field-of-view. The sampling time was as short as 0.24 ms. To measure the body bow-tie attenuation on a GE Lightspeed Pro 16 CT scanner, the x-ray tube was parked at the 12 o'clock position, and the detector was centered in the scan field at the isocenter height. Two radiation exposures were made with and without the bow-tie in the beam path. Each readout signal was corrected for the detector background offset and signal-level related nonlinear gain, and the ratio of the two exposures gave the bow-tie attenuation. The results were used in the geant4 based simulations of the point doses measured using six thimble chambers placed in a human cadaver with abdomen/pelvis CT scans at 100 or 120 kV, helical pitch at 1.375, constant or variable tube current, and distinct x-ray tube starting angles. Absolute attenuation was measured with the body bow-tie scanned at 80-140 kV. For 24 doses measured in six organs of the cadaver, the median or maximum difference between the simulation results and the measurements on the CT scanner was 8.9% or 25.9%, respectively. The described method allows fast and accurate bow-tie filter characterization.

Multi-spot laser lock-in thermography for real-time imaging of cracks in semiconductor chips during a manufacturing process

This article proposes a new multi-spot laser lock-in thermography (MLLT) system for real-time imaging of cracks in semiconductor chips. The proposed MLLT system is able to inspect a semiconductor chip in real-time during its manufacturing process by simultaneously generating thermal waves on multiple points of the target semiconductor chip surface using multi-spot pulsed laser beams and measuring the corresponding thermal responses using a high-speed infrared (IR) camera. In particular, the MLLT system offers the following advantages for the semiconductor chip inspection: (1) complete non-contact, non-destructive and non-intrusive inspection, (2) real-time crack inspection with fast data acquisition and processing, (3) baseline-free crack visualization using only current-state data, making it possible to avoid false alarms caused by operational and environmental variations and (4) high detectability of cracks. To realize the MLLT system, optical components for multi-spot thermal wave generation are designed through an optical analysis and integrated with the high-speed IR camera, a close-up lens and a personal computer. The developed MLLT system is then experimentally demonstrated using actual semiconductor chips with real cracks produced during the manufacturing process. The experimental results reveal that the total inspection time including the data acquisition and processing takes less than 1s for each semiconductor chip, and cracks in the range of 20μm are successfully detected.

0.5 billion events per second time correlated single photon counting using CMOS SPAD arrays.

We present a digital architecture for fast acquisition of time correlated single photon counting (TCSPC) events from a 32×32 complementary metal oxide semiconductor (CMOS) single photon avalanche detector (SPAD) array (Megaframe) to the computer memory. Custom firmware was written to transmit event codes from 1024-TCSPC-enabled pixels for fast transfer of TCSPC events. Our 1024-channel TCSPC system is capable of acquiring up to 0.5×10(9) TCSPC events per second with 16 histogram bins spanning a 14 ns width. Other options include 320×10(6) TCSPC events per second with 256 histogram bins spanning either a 14 or 56 ns time window. We present a wide-field fluorescence microscopy setup demonstrating fast fluorescence lifetime data acquisition. To the best of our knowledge, this is the fastest direct TCSPC transfer from a single photon counting device to the computer to date.

Zero volt paper spray ionization mass spectrometry for direct analysis of samples on filter paper substrate.

Zero volt paper spray ionization (zvPSI) is a newly developed sample introduction/ionization technique for mass spectrometry (MS), which combines favorable features of paper spray ionization (PSI) and solvent-assisted inlet ionization (SAII). With a simple platform similar to PSI, zvPSI allows direct MS analysis of a broad type of samples (liquid, (semi-)solid, and imprint) without applying voltage. In zvPSI-MS, a rectangular paper slip was used as a sample loader, extraction medium, and droplet emitter to introduce sample extract into the inlet of a mass spectrometer. For (semi-)solid and imprint samples, analyte(s) was directly extracted with solvent and instantaneously introduced into a mass spectrometer by aspiration. Solution samples were analyzed after being dried-up or by dispensing directly onto paper. Ionization was achieved by SAII and ionized molecules were detected by an ion-trap mass spectrometer. The developed method allowed direct voltage-free MS analysis of samples on filter paper substrate. Favorable features of PSI and SAII were successfully combined, such as fast data acquisition, flexible sample handlings, and direct extraction capability from solid samples (PSI), with no need for external high-voltage, laser, or nebulizing gas to convert analytes into gas-phase ions (SAII). Comparable to PSI and SAII, a wide variety of compounds such as amino acids, peptides, lipids and synthetic polymers were shown to be analyzed. The developed method (zvPSI-MS) expanded the analytical utility of PSI and SAII to voltage-free direct MS analysis of a broad type of samples (liquid, (semi-)solid, and imprint).

Development of a 50-T pulsed magnetic field facility by using an 1.5-MJ capacitor bank

Because DC magnets consume a huge amount of electricity (resistive DC magnet) or liquid helium (superconducting magnet), a capacitor-bank-driven pulsed magnet is known to be a cost-effective way of generating high magnetic fields. This type of pulsed magnet is normally operated at liquid nitrogen temperature and consumes little electric power to generate over 50 tesla (T) during a short transient time of less than 50 millisecond (ms). With modern fast data acquisition systems, almost all kinds of physical quantities, such as photoluminescence, magnetization or resistance can be measured during a short magnetic field pulse. We report a recently home-built capacitor-bankdriven pulsed magnetic field facility, in which a capacitor bank of 1.5-MJ maximum stored energy is utilized to generate pulsed magnetic fields up to 50 T with transient pulse time of 22 ms.