Rapid Scanning Research Articles

Effects of different sources of β-glucan on pasting, gelation, and digestive properties of pea starch

The effects of Lentinula edodes β-glucan (LG), yeast β-glucan (YG), and oat β-glucan (OG) on pasting, gelation, and digestive properties of pea starch (PeS) were studied. Because of different molecular weights and spatial conformation, β-glucan interacted differently with PeS. With the increase of molecular weight of OG, YG, and LG, the pasting property and the gelatinization enthalpy (ΔH) of β-glucan-PeS (G-PeS) suspension decreased by rapid viscosity analyzer and differential thermal scanning analysis, respectively, which was consistent with the results of X-ray diffraction; texture parameters of G-PeS gel were increased and the scanning electron microscope furtherly showed that the structure of 0.5% G-PeS gel was more stable. The rheological parameters (energy storage modulus (G′) and loss modulus (G″) of G-PeS were LG-PeS ≈ YG-PeS > OG-PeS. And the blue shift degree of absorption peak in the Fourier transform infrared spectrum of G-PeS gels (1639.09 cm −1 , 1639.12 cm −1 , and 1637.78 cm −1 ) proved that LG and YG with trihelix structure could form stronger hydrogen bonds with starch granules compared with OG without trihelix structure. In vitro simulated digestion experiments showed that the inhibition degree of β-glucan on the digestion rate of G-PeS was LG > YG > OG. Herein, adding β-glucan to pes starch has a big potential to promote the texture of PeS-based foods and help diabetics control postprandial glucose levels. • β-Glucan of oat (OG), yeast (YG) and Lentinula edodes (LG) enhanced the wrapping effect on pea starch (PeS) as molecular weight increased. • LG and YG with trihelix structure could form stronger hydrogen bonds with PeS compared to OG. • LG had the better inhibition effect on the digestion rate of PeS than YG and OG.

Interpulse stimulation Fourier-transform coherent anti-Stokes Raman spectroscopy

Exploiting the time-resolving ability of ultrafast pulses, Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) stands out among the coherent Raman spectroscopic techniques for providing high-speed vibrational spectra with high spectral resolution, high Raman intensity, and immunity to nonresonant background. However, the impulsive stimulation nature of FT-CARS imposes heavy demands on the laser source and makes it inherently difficult to monitor high-frequency vibrations. Here, a novel FT-CARS strategy to our knowledge based on interpulse stimulation is proposed to provide more flexible measuring wavenumber region and lighten the requirement on ultrafast pulses. The mechanism of this technique is analyzed theoretically, and simulation is performed to show an orders-of-magnitude improvement of Raman intensity in the high-wavenumber region by the method. Experimentally, an ytterbium-doped fiber laser and photonic crystal fiber-based solitons are employed to provide two ∼ 100 - fs pulses as the pump and Stokes, respectively, and to perform interpulse stimulation FT-CARS without sophisticated dispersion control devices. The high-wavenumber region and upper-part fingerprint region measurements are demonstrated as examples of flexible measurement. Combined with other rapid scanning techniques, such as resonant scanners or a dual-comb scheme, this interpulse stimulation FT-CARS promises to make the fascinating FT-CARS available for any desired wavenumber region, covering many more realistic scenarios for biomedical, pathological, and environmental research.

RECENT ADVANCES IN COMPUTED TOMOGRAPHY RADIATION DOSIMETRY

Computer tomography (CT) has proved fundamental in image evaluation throughout the past three decades. By combining rapid scanning with high-quality data sets, multi-detector technology continues to influence practice patterns. This has led to new applications and improved use in conventional applications. However, the increased use of CT has generated significant concern regarding the high radiation doses received by patients during CT scans compared to traditional radiography examinations. Many studies have been undertaken on minimizing patient dose and adhering to the as low as reasonably achievable (ALARA) principle. A total of 40 English articles from PubMed, Science Direct and Google Scholar were systematically summarized in this review paper to introduce the growth of CT scan from single-slice to multi-slice technology from 2000 until December 2020 as well as dual-energy and multi-detector CT technologies. The important role of utilizing CT radiation dosimeters for CT dose measurement is defined included CT dose reduction techniques.

High-Speed THz Time-of-Flight Imaging with Reflective Optics

In this study, we develop a 3D THz time-of-flight (TOF) imaging technique by using reflective optics to preserve the high-frequency components from a THz antenna. We use an Fe:InGaAs/InAlAs emitter containing relatively high-frequency components. THz-TOF imaging with asynchronous optical sampling (ASOPS) enables the rapid scanning of 100 Hz/scan with a time delay span of 100 ps. We characterize the transverse resolution using knife edge tests for a focal length of 5; the Rayleigh resolution has been measured at 1.0 mm at the focal plane. Conversely, the longitudinal resolution is determined by the temporal pulse width, confirmed with various gap structures enclosed by a quartz substrate. The phase analysis reveals that reflected waves from the top interface exhibit a phase shift when the gap is filled by high-indexed materials such as water but shows in-phase behavior when it is filled with air and low-indexed material. Our imaging tool was effective for inspecting the packaged chip with high lateral and longitudinal resolution. Importantly, the phase information in 2D and 3D images is shown to be a powerful tool in identifying the defect-in particular, delamination in the chip-which tends to be detrimental to the packaged chip's stability.

High-sensitivity fluorescence-detected multidimensional electronic spectroscopy through continuous pump-probe delay scan.

Fluorescence-detected multidimensional electronic spectroscopy (fMES) promises high sensitivity compared to conventional approaches and is an emerging spectroscopic approach toward combining the advantages of MES with the spatial resolution of a microscope. Here, we present a visible white light continuum-based fMES spectrometer and systematically explore the sensitivity enhancement expected from fluorescence detection. As a demonstration of sensitivity, we report room temperature two-dimensional coherence maps of vibrational quantum coherences in a laser dye at optical densities of ∼2-3 orders of magnitude lower than conventional approaches. This high sensitivity is enabled by a combination of biased sampling along the optical coherence time axes and a rapid scan of the pump-probe waiting time T at each sample. A combination of this approach with acousto-optic phase modulation and phase-sensitive lock-in detection enables measurements of room temperature vibrational wavepackets even at the lowest ODs. Alternative faster data collection schemes, which are enabled by the flexibility of choosing a non-uniform undersampled grid in the continuous T scanning approach, are also demonstrated.

Rapid Scan Electron Paramagnetic Resonance Spectroscopy Is a Suitable Tool to Study Intermolecular Interactions of Intrinsically Disordered Protein.

Intrinsically disordered proteins (IDPs) are involved in most crucial cellular processes. However, they lack a well-defined fold hampering the investigation of their structural ensemble and interactions. Suitable biophysical methods able to manage their inherent flexibility and broad conformational ensemble are scarce. Here, we used rapid scan (RS) electron paramagnetic resonance (EPR) spectroscopy to study the intermolecular interactions of the IDP α-synuclein (aS). aS aggregation and fibril deposition is the hallmark of Parkinson's disease, and specific point mutations, among them A30P and A53T, were linked to the early onset of the disease. To understand the pathological processes, research intensively investigates aS aggregation kinetics, which was reported to be accelerated in the presence of ethanol. Conventional techniques fail to capture these fast processes due to their limited time resolution and, thus, lose kinetic information. We have demonstrated that RS EPR spectroscopy is suitable for studying aS aggregation by resolving underlying kinetics and highlighting differences in fibrillization behavior. RS EPR spectroscopy outperforms traditional EPR methods in terms of sensitivity by a factor of 5 in our case while significantly reducing data acquisition time. Thus, we were able to sample short time intervals capturing single events taking place during the aggregation process. Further studies will therefore be able to shed light on biological processes proceeding on fast time scales.

Thin-film optical-acoustic combiner enables high-speed wide-field multi-parametric photoacoustic microscopy in reflection mode.

Multi-parametric photoacoustic microscopy (PAM) is uniquely capable of simultaneous high-resolution mapping of blood oxygenation and flow in vivo. However, its speed has been limited by the dense sampling required for blood flow quantification. To overcome this limitation, we have developed a high-speed multi-parametric PAM system, which enables simultaneous acquisition of ∼500 densely sampled B-scans by superposing the rapid optical scanning across the line-shaped focus of a cylindrically focused ultrasonic transducer over the conventional mechanical scan of the optical-acoustic dual foci. A novel, to the best of our knowledge, optical-acoustic combiner (OAC) is designed and implemented to accommodate the short working distance of the transducer, enabling convenient confocal alignment of the dual foci in reflection mode. A resonant galvanometer (GM) provides stabilized high-speed large-angle scanning. This new system can continuously monitor microvascular blood oxygenation (sO2) and flow over a 4.5 × 3 mm2 area in the awake mouse brain with high spatial and temporal resolutions (6.9 µm and 0.3 Hz, respectively).

TURBO: A novel beam delivery system enabling rapid depth scanning for charged particle therapy

Charged particle therapy (CPT) is a well-established modality of cancer treatment and is increasing in worldwide presence due to improved accelerator technology and modern techniques. The beam delivery system (BDS) determines the overall timing and beam shaping capabilities, but is restricted by the energy variation speed: energy layer switching time (ELST). Existing treatment beamlines have a ±1% momentum acceptance range, needing time to change the magnetic fields as the beam is delivered in layers at various depths across the tumour volume. Minimising the ELST can enable the delivery of faster, more effective and advanced treatments but requires an improved BDS. A possibility for this could be achieved with a design using Fixed Field Alternating Gradient (FFA) optics, enabling a large energy acceptance to rapidly transport beams of varying energies. A scaled-down, novel system – Technology for Ultra Rapid Beam Operation (TURBO) – is being developed at the University of Melbourne, to explore the potential of rapid depth scanning. Initial simulation studies, beam and field measurements, project plans and clinical considerations are discussed.

Rapid tunnel scanning using a 360-degree camera and SfM photogrammetry

Photogrammetric scanning can be employed for the digitization of underground spaces, for example for remote mapping, visualization, or training purposes. However, such a technique requires capturing many photos, which can be laborious and time-consuming. Previous research has demonstrated that the acquisition time can be reduced by capturing the data with multiple lenses or devices at the same time. Therefore, this paper demonstrates a method for rapid scanning of hard rock tunnels using Structure-from-Motion (SfM) photogrammetry and a 360-degree camera. The test was performed in the Underground Research Laboratory of Aalto University (URLA). The tunnel is located in granitic rocks at a depth of 20 m below the Otaniemi campus in Espoo, Finland. A 10 m long and 3.5 m high tunnel section with exposed rock was selected for this study. Photos were captured using the 360-degree camera from 27 locations and 3D models were reconstructed using SfM photogrammetry. The accuracy, speed, and resolution of the 3D models were measured and compared with models scanned with a digital single-lens reflex (DSLR) camera. The results show that the data capture process with a 360-degree camera is 6x faster compared to a conventional camera. In addition, the orientation of discontinuities was measured remotely from the 3D model and the digitally obtained values matched the manual compass measurements. Even though the quality of the 360-degree camerabased 3D model was visually inferior compared to the DSLR model, the point cloud had sufficient accuracy and resolution for semi-automatic discontinuity measurements. The quality of the models can be improved by combining 360-degree and DSLR photos which result in a point cloud with 3x higher resolution and 2x higher accuracy. The results demonstrated that 360-degree cameras can be used for the rapid digitization of underground tunnels.

Method to obtain 3D point clouds of tunnels using smartphone LiDAR and comparison to photogrammetry

Remote sensing methods, for example, photogrammetry and laser scanning can be employed to scan rock masses by digitizing underground spaces or slopes. To reconstruct a 3D model by photogrammetry, plenty of photos should be captured. This process is time-consuming and can be dangerous when the rock mass is unstable. Therefore, rapid capturing methods are needed to reduce the acquisition time. This can be achieved with LiDAR scanners that capture a 3D point cloud with a high-speed pulsed laser beam. However, the cost of laser scanners is high, which limits their usability. Apple’s iPhone 12 Pro Max smartphone is equipped with a LiDAR sensor and is much cheaper than conventional laser scanners. Several mobile applications for 3D models using the smartphone Lidar have been developed, making the scanning process easy. Therefore, smartphones can be used for rapid scanning of unstable surfaces of tunnels and slopes. In this study, 3D point clouds (3DPC) of a tunnel wall of the Underground Research Laboratory of Aalto University (URLA) are obtained by a high-resolution digital camera and smartphone LiDAR. The models are analyzed and compared. The results show the quality of the smartphone LiDAR sensor is adequate for generating 3D models of underground spaces.

Mechanistic stages of the SCR reaction – Insights into the trade-off between NO reduction and NH3 oxidation over CuSSZ-13 catalysts via isotopic 15NH3 and 18O2 TPSR and steady state studies supported by IR 2D COS and DFT modeling

Isotopic labeling investigations into SCR reaction were performed over CuSSZ-13 zeolites, obtained by one-pot synthesis or impregnation, and characterized by XRD, HR-SEM, TEM/EDX, EPR, and IR techniques. The course of SCR and internal ammonia oxidation (i-AMO) was revealed by isotopic TPSR and steady-state investigations using 15NH3 and 18O2 joined with IR Rapid Scan 2D-COS spectroscopy. The 14N15N and 15N2 profiles allowed for quantification of the relative contributions of the concurrent SCR and i-AMO reactions. Interpretation of the results was ascertained by DFT and first-principles thermodynamic modeling. Three temperature regions of SCR reactions, corresponding to NH3-rich, lean and dry conditions, were distinguished, and the main processes and intermediates involved in each stage were identified. For the conceptualization of SCR, a 2D diagram of the reactants and intermediates stoichiometry, oxidation state, and charge commensurability was constructed, and used for rationalization of the reaction mechanism.

Physico-Chemical Properties of Cross-linked and Hydroxypropyl White Sorghum (sorghum bicolor) Starch

The study investigated the effects of cross-linking and hydroxypropylation on some physico-chemical properties of white sorghum (sorghum bicolor) starch. The sorghum starch (NSS) was isolated and chemically modified by hydroxypropylation with propylene oxide and by cross-linking with epichlorohydrin. The swelling, solubility and other physico-chemical properties of the starch was determined. The pasting property and the granule morphology of the starches were also determined using Rapid Visco-Analyzer and Scanning Electron Microscope respectively. Changes in chemical structure of the starch molecule were confirmed by FT-IR. The amylose content (27.01%) of the native sorghum starch decreased after modifications to (20.11 and 18.81) % for cross-linked, and hydroxylpropyl sorghum starches while the starch solubility and swelling increased in the temperature range (50 – 90oC), with the native starch having the highest values. Hydroxylpropyl sorghum starch (PSS) however has better swelling power in all the temperature range when compared with cross-linked sorghum starch (CSS). The shape of the starch granules was mainly spherical and polygonal with various diameters ranging from 6 to 22 μm, however modification does not have any pronounced effect on the starch granules. Hydroxypropylation reduced the breakdown viscosity of the native sorghum starch from 1630 to 1048 RVU, the peak viscosity of sorghum starch decreased from 2779 RVU for the native starch (NSS) to 2731 RVU in CSS. In conclusion, the modifications employed improved the physiochemical properties of sorghum starch and hence the modified starch could be used industrially.

Evaluation of LiDAR-Derived Features Relevance and Training Data Minimization for 3D Point Cloud Classification

Terrestrial laser scanning (TLS) is a leading technology in data acquisition for building information modeling (BIM) applications due to its rapid, direct, and accurate scanning of different objects with high point density. Three-dimensional point cloud classification is essential step for Scan-to-BIM applications that requires high accuracy classification methods, running at reasonable processing time. The classification process is divided into three main steps: neighborhood definition, LiDAR-derived features extraction, and machine learning algorithms being applied to label each LiDAR point. However, the extraction of LiDAR-derived features and training data are time consuming. This research aims to minimize the training data, assess the relevance of sixteen LiDAR-derived geometric features, and select the most contributing features to the classification process. A pointwise classification method based on random forests is applied on the 3D point cloud of a university campus building collected by a TLS system. The results demonstrated that the normalized height feature, which represented the absolute height above ground, was the most significant feature in the classification process with overall accuracy more than 99%. The training data were minimized to about 10% of the whole dataset with achieving the same level of accuracy. The findings of this paper open doors for BIM-related applications such as city digital twins, operation and maintenance of existing structures, and structural health monitoring.

Charge-separation driven mechanism via acylium ion intermediate migration during catalytic carbonylation in mordenite zeolite

By employing ab initio molecular dynamic simulations, solid-state NMR spectroscopy, and two-dimensional correlation analysis of rapid scan Fourier transform infrared spectroscopy data, a new pathway is proposed for the formation of methyl acetate (MA) via the acylium ion (i.e.,CH3 − C ≡ O+) in 12-membered ring (MR) channel of mordenite by an integrated reaction/diffusion kinetics model, and this route is kinetically and thermodynamically more favorable than the traditional viewpoint in 8MR channel. From perspective of the complete catalytic cycle, the separation of these two reaction zones, i.e., the C-C bond coupling in 8MR channel and MA formation in 12MR channel, effectively avoids aggregation of highly active acetyl species or ketene, thereby reducing undesired carbon deposit production. The synergistic effect of different channels appears to account for the high carbonylation activity in mordenite that has thus far not been fully explained, and this paradigm may rationalize the observed catalytic activity of other reactions.

Characteristics of a Jumping Cirrus Retrieved From Rapid Scans by Himawari‐8

AbstractA jumping cirrus (JC) is a cloud that forms a few kilometers above an anvil cloud downwind of an overshooting top (OT). A JC transports water vapor from the troposphere into the stratosphere, where water vapor is an important greenhouse gas. However, the microphysics of JC has not been explored thus far. Herein, 2.5‐min rapid scan images obtained from the geostationary weather satellite Himawari‐8 were analyzed for JC observations. A dark plume was observed to appear suddenly above an anvil cloud downwind of OTs and moved 1 km upwind within 2.5 min. The brightness temperature of the plume showed that it overlaid the anvil cloud. These characteristics matched those of a JC. The reflectivity of the assumed JC at a wavelength of 0.64 μm was 0.62, whereas that of the anvil cloud on the sunny side of the JC was 1.02. The measured reflectivities were compared to those simulated using ray tracing to retrieve the microphysics of the JC. The results indicated that dark reflectivity occurred because the JC was isolated above the anvil cloud, and bright reflectivity occurred because the anvil was illuminated by the sun and scattered light from the JC. The retrieved effective radius and ice water content of the JC were 23.4–28.0 μm and 0.12–0.15 g m−3, respectively. The JC appeared to transport 10 × 103 t of ice water above deep convection within 10 min. We applied the results to analyzing the best satellite geometry for detecting and measuring JC.

A high throughput rapid scanning dispersive spectrometer for longwave infrared absorption spectroscopy

A rapid-scanning spectrometer was constructed to capture several hundred wavenumber wide spectral scans at greater than 1 kHz repetition rate in the longwave infrared. The system, made from commercial-off-the-shelf components, exceeds scan width and repetition rate limitations present in other infrared diagnostics while maintaining better than 10 cm−1 spectral resolution through its high throughput (f/2) design. Instrument design and construction is discussed in detail, and validation of the spectrometer’s ability to capture time resolved spectra in the 800–1400 cm−1 region at 1.2 kHz was demonstrated through the measurement of organophosphorus chemical nerve agent simulant destruction inside high explosive fireballs.

A novel anthropomorphic breathing phantom with a pneumatic MR-safe actuator for tissue deformation studies during MRI and radiotherapy

A novel MR-safe anthropomorphic torso phantom with an MR-conditional pneumatic respiration system and inflatable lungs for tissue deformation studies is proposed. The phantom consists of a pair of lungs made from sponges encased in flexible polyurethane. The lung phantom also contains a set of silicone tubes of various diameters to mimic the larger vasculature and airways of the lungs. The lungs are surrounded by a plastic ribcage and immersed in a gelatine hydrogel within a flexible polyurethane skin. A plastic pneumatic pump system was constructed to inflate and deflate the lungs. A fibre optic rotary encoder was constructed to determine the volume of displaced air in the lungs. The pneumatic pump and rotary encoder were constructed of plastic materials to allow placement within the bore of the MR scanner with minimal interaction with the magnetic field. Breath-gated scans and rapid imaging scans (2.5 s per image) were taken of the phantom in the stationary state and during inflation/deflation, and with Cartesian and BLADE k-space sampling. It was found that BLADE shows the least motion artifacts during breathing. This phantom and respiration system shows potential for quality assurance of MRI incorporating breathing corrections and for radiotherapy applications in tracking a moving target.

Rapid 40S scanning and its regulation by mRNA structure during eukaryotic translation initiation

How the eukaryotic 43S preinitiation complex scans along the 5' untranslated region (5' UTR) of a capped mRNA to locate the correct start codon remains elusive. Here, we directly track yeast 43S-mRNA binding, scanning, and 60S subunit joining by real-time single-molecule fluorescence spectroscopy. 43S engagement with mRNA occurs through a slow, ATP-dependent process driven by multiple initiation factors including the helicase eIF4A. Once engaged, 43S scanning occurs rapidly and directionally at ∼100 nucleotides per second, independent of multiple cycles of ATP hydrolysis by RNA helicases post ribosomal loading. Scanning ribosomes can proceed through RNA secondary structures, but 5' UTR hairpin sequences near start codons drive scanning ribosomes at start codons backward in the 5' direction, requiring rescanning to arrive once more at a start codon. Direct observation of scanning ribosomes provides a mechanistic framework for translational regulation by 5' UTR structures and upstream near-cognate start codons.

Real time FT-IR observation of materials during their cooling from molten state

A new methodology allowing real time observation of materials during their cooling, from the molten state to low temperature has been developed. This possibility originates from the implementation of a Rapid Scan feature on a FT-IR emissometer designed to probe materials submitted to extreme temperature conditions. Original time-resolved emissivity dependence during the phase transition are reported for the first time. The resulting out of equilibrium, dynamic, new data have been compared to the equilibrium, static, classical measurements to demonstrate the reliability of the new technique on two reference samples (Al2O3 and SiO2). The proposed method has high possibilities to be applied to different materials to enable the observation of fast structural transformations during liquid to solid phase change through the evolution of the dielectric function.

Integrated continuous flow method with dual feedback-based controls for online analysis and process control.

The concept of an integrated automated continuous flow method with dual feedback controls is presented for diluting a stock solution to provide a solution of a given concentration. The one control is used for the online process monitoring by a feedback-based flow ratiometry, where the product (the diluted liquid) is titrated through the rapid bidirectional scan of the product/reagent flow ratio. The feedback control limits the scanning to the necessary range to increase the analytical throughput. The other control is used for the process control to output the product with a preset concentration. The merging ratio of the stock solution and a solvent (diluent) is changed based on the information from the online analysis. The concept was verified by applying it to producing 0.1moldm-3 CH3COOH. When the stock concentration was changed from 0.1 (reference concentration) to 0.3 and then 0.2moldm-3, the system searched for the suitable merging ratio and converged the output concentration to the reference value within 7.43min with a relative error below 1.05%. The mean throughput rate of the process analysis was 11.2 titrations min-1. Successful results were also obtained for the 0.1moldm-3 HCl production. The present concept could be the basis for process control with reduced wasteful output and effluent treatment with eco-friendly treated water discharge, resulting in the contribution to SDGs' goals of 6 (Clean water and sanitation), 9 (Industry, innovation and infrastructure), and 14 (Life below water).