Scan Mode Research Articles

A miniaturized comprehensive approach for total lipidome analysis and vitamin D metabolite quantification in human serum.

The balance between the different lipid molecules present in biological fluids accurately reflects the health state of the organism and can be used by medical personnel to finely tune therapy to a single patient, a process known as precision medicine. In this work, we developed a miniaturized workflow for the analysis of different lipid classes at theintact level, as well as their fatty acid constituents, starting from human serum. Fatty acids were identified by using flow-modulated comprehensive gas chromatography coupled to mass spectrometry (FM-GC × GC-MS), and their relative amount as well as the ratio of specific FA classes was determined by using FM-GC × GC with a flame ionization detector. Ultra-high-performance liquid chromatography coupled to tandem mass spectrometry was used for the simultaneous quantification of vitamin D metabolites and assessment of different intact lipid classes. An MRM method was developed for the quantification of five vitamin D metabolites (vitamin D2, vitamin D3, 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, 24R,25-dihydroxyvitamin D3), and validated in terms of LoD, LoQ, accuracy, and precision, also using a certified reference material. At the same time, a combination of SCAN, precursor ion scan, and neutral loss scan, in both positive and negative modes, was used for the identification of 81 intact lipid species, such as phospholipids, cholesteryl esters, and triacylglycerols, in less than 25min. In order to easily monitor the lipid composition and speed up the identification process, a two-dimensional map of the lipidome was generated, by plotting the molecular weight of the identified molecules versus their retention time. Moreover, a relative quantification was performed within each lipid class identified. The combination of untargeted and targeted data could provide useful information about the pathophysiological condition of the organism and evaluate, in a tailored manner, an efficient action.

The effect of different spatial resolutions and enhancement filters on radiographic detection of simulated furcation defects with intraoral digital radiography

The objective of this study was to evaluate the effects of spatial resolution and the application of enhancement filters in the diagnosis of simulated furcation defects and image quality with intraoral radiographs. Periapical images were acquired with photostimulable phosphor plates of molars in dry skulls (n=8) and mandibles (n=10) with 4 stages of furcation defect simulation. The plates were scanned in fast scan and high resolution modes to produce different spatial resolutions. Four image filters were applied. Six observers scored the detection of furcation defects. Mean values of area under the curve in receiver operating characteristic evaluation, accuracy, sensitivity, and specificity were calculated. Mean gray value (brightness), noise, and contrast-to-noise ratio (CNR) were calculated for enamel, dentin, and alveolar bone to evaluate image quality. Analysis of variance compared the values between the different spatial resolutions and filters. The significance of difference was established at P < .05. There were no significant differences in overall diagnostic values comparing image spatial resolutions and filters. Diagnostic outcomes were significantly better for the largest defects than the smallest lesions but were generally poor in detecting lesions. All structures showed greater brightness in high resolution. . Noise was greater in all structures with all enhancement filters except inversion. Dentin and alveolar bone exhibited more noise and lower CNR in high resolution. Varying spatial resolution and applying enhancement filters did not significantly affect the diagnosis of furcation defects.

Offline analysis of secondary formation markers in ambient organic aerosols by liquid chromatography coupled with time-of-flight mass spectrometry

The present study provides a comprehensive assessment of the quantitative analysis by high-performance liquid chromatography coupled with dual orthogonal electrospray ionization time-of-flight mass spectrometry (HPLC-ESI-TOF-MS) of pinene markers, biomass-burning related phenols, and other relevant carboxylic acids in atmospheric aerosol samples. Significant insights into the quantitative determination are offered on the basis of systematic experiments targeting the optimization of chromatographic separation, ionization source, and mass spectrometer performance. After testing three analytical columns, the best separation of the compounds of interest was achieved on a Poroshell 120 ECC18 column (4.6 × 50 mm, 2.7 µm) thermostated at 35 °C, operating in gradient elution mode with 0.1% acetic acid in water and acetonitrile at a 0.8 mL min−1 flow rate. Optimal operational conditions for the ESI-TOF-MS instrument were identified as a 350 °C drying gas temperature, 13 L min−1 drying gas flow rate, 60 psig nebulizer pressure, 3000 V for the ion transfer capillary, 60 V for the skimmer, and 150 V for the fragmentor. Additionally, the matrix effect on the ESI efficiency and the spike recovery factors of the compounds were tested. Method quantification limits can go as low as in the 0.88–48.0 μg L − 1 (3.67–200 pg m − 3, at 120 m3 of sampled air) range. The developed method was shown to be reliable for the quantification of the targeted compounds in real atmospheric aerosol samples. The accuracy in the molecular mass determination of less than 5 ppm and the acquisition in the full scan mode were shown to bring additional insights into the organic constituents in atmospheric aerosols.

Low-Variance Surface-Enhanced Raman Spectroscopy Using Confined Gold Nanoparticles over Silicon Nanocones.

Surface-enhanced Raman spectroscopy (SERS) substrates are of utmost interest in the analyte detection of biological and chemical diagnostics. This is primarily due to the ability of SERS to sensitively measure analytes present in localized hot spots of the SERS nanostructures. In this work, we present the formation of 67 ± 6 nm diameter gold nanoparticles supported by vertically aligned shell-insulated silicon nanocones for ultralow variance SERS. The nanoparticles are obtained through discrete rotation glancing angle deposition of gold in an e-beam evaporating system. The morphology is assessed through focused ion beam tomography, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The optical properties are discussed and evaluated through reflectance measurements and finite-difference time-domain simulations. Lastly, the SERS activity is measured by benzenethiol functionalization and subsequent Raman spectroscopy in the surface scanning mode. We report a homogeneous analytical enhancement factor of 2.2 ± 0.1 × 107 (99% confidence interval for N = 400 grid spots) and made a comparison to other lithographically derived assemblies used in SERS. The strikingly low variance (4%) of our substrates facilitates its use for many potential SERS applications.

MS-Based Proteomics of Body Fluids: The End of the Beginning

Accurate biomarkers are a crucial and necessary precondition for precision medicine, yet existing ones are often unspecific and new ones have been very slow to enter the clinic. Mass spectrometry (MS)-based proteomics excels by its untargeted nature, specificity of identification, and quantification, making it an ideal technology for biomarker discovery and routine measurement. It has unique attributes compared to affinity binder technologies, such as OLINK Proximity Extension Assay and SOMAscan. In in a previous review in 2017, we described technological and conceptual limitations that had held back success. We proposed a ‘rectangular strategy’ to better separate true biomarkers by minimizing cohort-specific effects. Today, this has converged with advances in MS-based proteomics technology, such as increased sample throughput, depth of identification, and quantification. As a result, biomarker discovery studies have become more successful, producing biomarker candidates that withstand independent verification and, in some cases, already outperform state-of-the-art clinical assays. We summarize developments over the last years, including the benefits of large and independent cohorts, which are necessary for clinical acceptance. Shorter gradients, new scan modes, and multiplexing are about to drastically increase throughput, cross-study integration, and quantification, including proxies for absolute levels. We have found that multiprotein panels are inherently more robust than current single analyte tests and better capture the complexity of human phenotypes. Routine MS measurement in the clinic is fast becoming a viable option. The full set of proteins in a body fluid (global proteome) is the most important reference and the best process control. Additionally, it increasingly has all the information that could be obtained from targeted analysis although the latter may be the most straightforward way to enter regular use. Many challenges remain, not least of a regulatory and ethical nature, but the outlook for MS-based clinical applications has never been brighter.

Determination of thermal and mechanical indices of an ultrasound probe with an inclined beam-axis in accordance with the new JIS (or IEC Standards)

According to the new JIS (or IEC Standards), it is necessary to measure the bounded-square output power (P 1×1) for the determination of the soft tissue thermal index (TIS) for both scanning and non-scanning modes of an ultrasonic diagnostic equipment. However, there is no report about how to measure P 1x1 for an ultrasound probe with an inclined beam-axis (UPIB). We designed an angle-corrected 1 cm × 1 cm absorbing mask in accordance with the spirit of IEC 62359 Ed. 2.0 and established a reasonable process for the measurement of TIS and mechanical index (MI) of a paste type probe (PTP), which is a specially designed UPIB for examination of the blood flow in a carotid artery more conveniently and efficiently. Both the TIS and MI of the PTP were much less than 1.0 at all selectable presettings of the blood flow monitor, the FURUHATA device, suggesting it is as safe as a common ultrasonic Doppler diagnostic device.

Rapid determination of 48 stimulant residues in milk and dairy products by high-performance liquid chromatography coupled with quadrupole/Orbitrap high-resolution mass spectrometry

A fast and easy method was proposed for the determination and quantification of 48 stimulants in milk and dairy products using high-performance liquid chromatography coupled with quadrupole/electrostatic field Orbitrap high-resolution mass spectrometry (Q Exactive). The samples were extracted with acetonitrile having 0.1% formic acid, and then, the extracting solution was purified using a Captive EMR-LIPID solid-phase extraction column. The main force between the target compound and the adsorbent was size exclusion. Unbranched long aliphatic chains on the lipids entered the sorbent, while bulky analytes did not, which could effectively remove the phosphorus esters in dairy products. Finally, we determined the instrument conditions. The samples were separated on a C18 column and eluted with acetonitrile and 0.05% formic acid aqueous solution as the mobile phases. Determination was then performed by mass spectrometry in electrospray ion source mode and monitored in parallel by reaction monitoring full scan/data-dependent secondary scan (Full MS/DD-MS2) mode. Under optimal conditions, the limit of quantification for the 48 stimulants was 0.5–100 µg L−1 in the milk and dairy products samples. The recoveries were 60.6–118.9% for milk, 63.2–123.8% for milk powder, and 61.8–119.6% for yogurt, with a determined coefficient of variation of less than 15%. The limit of detection values was 0.1–5.0 µg kg−1, and the limit of quantification values for the analytes was 0.2–10.0 µg kg−1. Finally, this method was used to screen 48 stimulants in 50 milk and dairy product samples.

A novel approach for improved honey identification and scientific definition: a case of buckwheat honey

This study aimed to provide insights into a novel honey screening and authentication approach. Chemometrics associated with a GC/MS instrumentation was applied to verify a total of 13 honey samples having different floral and geographical origin with an aim to detect buckwheat honey and discriminate it from honeys of other floral sources. Non-polar and semi-polar compounds were first extracted and then detected and semi-quantified employing a GC/MS device working in a full scan mode. Fingerprinting signals covering peaks that elute in the first 20 min, comprising 2000 scans of semi-polar compounds, were used as input datasets for unsupervised and supervised chemometric tools. This approach demonstrated excellent classification performances of honey samples according to the declared floral source, regardless of their geographical origin. The obtained results were compared with the outputs of a common melissopalynological procedure. Although exhibiting a high variability in the pollen content, samples declared as buckwheat honey demonstrated similar chemical profiles. The proposed non-targeted and semi-quantitative method showed to be rapid, unbiased, independent of tedious qualitative and quantitative determinations of eluting compounds, thus exhibiting a strong potential to be incorporated into data fusion procedures for honey authentication. Harmonising chemical methodologies with certain indications from pollen analysis to form core-data systems would undoubtedly improve the authentication protocols of honey floral sources.

An AI model to estimate visual acuity based solely on cross-sectional OCT imaging of various diseases.

To develop an artificial intelligence (AI) model for estimating best-corrected visual acuity (BCVA) using horizontal and vertical optical coherence tomography (OCT) scans of various retinal diseases and examine factors associated with its accuracy. OCT images and associated BCVA measurements from 2,700 OCT images (accrued from 2004 to 2018 with an Atlantis, Triton; Topcon, Tokyo, Japan) of 756 eyes of 469 patients and their BCVA were retrospectively analysed. For each eye, one horizontal and one vertical OCT scan in cross-line mode were used. The GoogLeNet architecture was implemented. The coefficient of determination (R2), root mean square error (RMSE) and mean absolute error (MAE) were computed to evaluate the performance of the trained network. R2, RMSE, and MAE were 0.512, 0.350, and 0.321, respectively. R2 was higher in phakic eyes than in pseudophakic eyes. Multivariable regression analysis showed that a higher R2 was significantly associated with better BCVA (p < 0.001) and a higher standard deviation of BCVA (p < 0.001). However, the performance was worse in an external validation, with R2 of 0.19. R2 values for retinal vein occlusion and age-related macular degeneration were 0.961 and 0.373 in the internal validation but 0.20 and 0.22 in the external validation. Although underspecification appears to be a fundamental problem to be addressed in AI models for predicting visual acuity, the present results suggest that AI models might have potential for estimating BCVA from OCT in AMD and RVO. Further research is needed to improve the utility of BCVA estimation for these diseases.

Direct Analysis of Bio-Molecules in Solid Materials Using Electrospray Ionisation Mass Spectrometry Coupled with Laser Ablation and a Liquid Sampling Technique.

In situ and rapid analysis of organic compounds using a combination of a newly-developed laser ablation in liquid (LAL) sampling technique combined with electrospray ionisation mass spectrometry (ESI-MS) is reported. The LAL is a technique that allows laser ablation to be conducted in a liquid medium containing organic compounds that were effectively extracted from solid materials into the liquid medium. Three organic compounds (valine, caffeine, and benzyl butyl phthalate (BBP)) were subjected to analysis. The LAL sampling was conducted in the fast-laser scanning mode using Galvanometric optics, and the total ablation time required for the sampling from a 1 mm2 area was about 3 s, thus providing rapid sampling. The resulting sample solution was directly introduced into the ESI-MS system, without the need for any chromatographic separation. To evaluate the analytical capability of the LAL technique coupled with ESI-MS, both the overall transmission efficiencies of analytes from solid materials to the ion detector, and the repeatabilities of the measurements were rigorously tested. This involved the use of synthetic, in-house prepared standard materials containing the analytes. The overall ion yields were about 1.1×10-3% for valine, 8.7×10-3% for caffeine, and 6.7×10-4% for BBP. By comparing the ion yields obtained by the injection of an analyte solution and a standard solution through the mass spectrometer, the recoveries through the LAL sampling were approximately 31% for valine, 45% for caffeine, and 37% for BBP. In addition, the analytical repeatabilities for all analytes were better than 6%. The analytical repeatabilities were mainly affected by either the heterogeneity of the in-house standard materials or changes in the plasma temperature by coexisting, laser-induced sample particles. It should be noted that not only water-soluble compounds (caffeine and valine), but also non-soluble compound (BBP) could be measured by the LAL-ESI-MS, which is one of the great advantages over the conventional liquid extraction surface analysis technique. The data obtained here clearly demonstrate that the LAL-ESI-MS has the potential for being a fast and user-friendly analytical technique for the in-situ detection for both the water-soluble and water-insoluble molecules.

Pharmacokinetic Study and Metabolite Identification of CAM106 in Rats by Validated UHPLC-MS/MS.

Given the limitations of existing antiviral drugs and vaccines, there is still an urgent need for new anti-influenza drugs. CAM106, a rupestonic acid derivative, was studied for its potent antiviral activity and showed a favorable inhibitory effect on influenza virus replication. However, many gaps exist in preclinical studies of CAM106. This study focused on the pharmacokinetic profile and metabolites of CAM106 in vivo. An efficient and fast bioanalytical method was successfully developed and validated for the quantitation of CAM106 in rat plasma. A mobile phase aqueous solution (A, containing 0.1% formic acid) and acetonitrile (B) worked within 0-3.5 min, with 60% B. The mass spectrum scanning mode was the parallel reaction monitoring (PRM) with a resolution of 17,500. The linear range of the method was 2.13-1063.83 ng/mL. The validated method was applied to a pharmacokinetic study in rats. The matrix effects ranged from 93.99% to 100.08% and the recovery ranged from 86.72% to 92.87%. The intra- and inter-day precisions were less than 10.24% and the relative error (RE) ranged from -8.92% to 7.1%. The oral bioavailability of CAM106 was 1.6%. Thereafter, its metabolites in rats were characterized using high-resolution mass spectrometry. The isomers M7-A, M7-B, M7-C, and M7-D were well separated. As a result, a total of 11 metabolites were identified in the feces, urine, and plasma of rats. The main metabolic pathways of CAM106 were oxidation, reduction, desaturation, and methylation. The assay was reliable and provided useful information for further clinical studies of CAM106.

Transitions between surface force- and inertia-dominant contact dynamics regimes in high-speed scanning probe microscopy

In contact mode scanning probe microscopy (SPM), the microcantilever probe’s dynamics are governed by the (short-range) surface interaction forces, where the tip is “always-in-contact” with the sample. In intermittent contact modes such as “tapping” or bimodal SPM, on the other hand, these are governed by the frequency of the microcantilever’s own external excitation. However, when contact mode is employed with high scan speeds (for “video-rate” SPM), we see intermittent transitions—within a single oscillation cycle—between the “always-in-contact” regime and another which is dominated by the microcantilever’s inertia. We find—through experiments and physical modeling—that the fast in-plane motion of the sample relative to the probe results in a high surface excitation frequency v/λ (and its harmonics), which excite the microcantilever’s out-of-plane eigenmodes and cause it to “break free” of the surface and “overshoot” and “parachute.” The impacts of the tip that consequently occur upon the sample inject energy over a wide frequency band into the higher eigenmodes, especially when operating in a low dissipation ambient environment. The microcantilever, then, exhibits phenomena such as eigenmode switching, sidebands, and fractional and combination resonances; such behavior is not seen in, say, tapping mode SPM, since, there, energy is injected at an externally-determined temporal rate. This article investigates the transition from the dynamics of the microcantilever at low speeds to that exhibited at high speeds. The model for dynamic contact loss is validated against the experiments and can be used to propose mitigation of such dynamics in order to achieve high-resolution imaging.

Preliminary Study on Automatic Detection of Hard Defects in Integrated Circuits Based on Thermal Laser Stimulation

Locating the fault position is a crucial part of the failure mechanism analysis of integrated circuits. This paper proposes a hard defect locating system based on Thermal Laser Stimulation (TLS) technology. The equation for laser-induced changes in the electrical parameters of semiconductor devices is a good guide to the hardware and software design of the hard defect locating system. The scanning mode of fast total scanning combined with slow point-to-point scanning can quickly locate abnormal areas. A modified median absolute difference (MAD) method is applied to the extraction of anomalous data. The system software can automatically and collaboratively control the 3D mobile station, laser, and signal acquisition unit. It also can intuitively display the distribution of abnormal points on the infrared image. Using a failure MRAM chip and a good one to conduct a comparative test, the abnormal points distributed on the infrared image of the chip indicate that the failure area is in the digital module or eFuse module of the chip, and the Emission Microscopy (EMMI) experiment also verifies the accuracy of the test system.

Enhancing the radar system simulator tool suite to allow the simulation of sensor networks

The number of human-made objects orbiting the Earth is growing steadily. This trend is further accelerating during recent years due to increasing commercialization in the field of satellite operations and an increasing launch rate. Concerning the area of space surveillance and tracking (SST), this leads to higher demands with respect to object observation capabilities. In order to ensure the safe usability of the different Earth orbits for all spacecraft operators, it is of great importance to continuously observe and catalog as many of the human-made objects as possible. This is especially true for inactive and uncontrollable objects, i.e. space debris. Only by maintaining accurate catalogs of the space debris environment, involuntary collisions can be avoided and risks of losing a spacecraft kept low. While the number of space debris objects can only be expected to further increase, it is not trivial to increase the number of observation sites, such as telescopes and radars, or their capabilities to counter this. One way to increase the observation capabilities without constructing new observation sites is to search for possibilities to improve the efficiency with which the existing sensors observe objects.With the goal to study and analyze single sensors, sensor networks, and how they can be used in the most efficient way, a sensor network simulator tool suite has been developed at the Institute of Space Systems of the Technical University of Braunschweig. Originally, the tool suite was developed as a radar system simulator concentrating on the different radar system configurations, such as reflector antennas or phased arrays that are used in a mono- or bistatic mode. Additionally, the corresponding radar performance model is able to simulate a tracking as well as a scanning mode. Building upon this tool suite, it is now extended to include an optical performance model and the possibility to simulate not only ground-based but also space-based sensors. Within this work, the preliminary results obtained with the newly implemented optical performance model are shown.Using the enhanced version of this sensor network simulator tool suite, thorough analyses can now be made using the radar and optical performance models. Sensor networks consisting of radars and telescopes being both ground- or space-based can be studied in different configurations. Thereby, different aspects, such as observation strategies, sensor tasking, or choosing the right location and sensor to reach a certain goal can be investigated.

Rapid determination of five common toxic alkaloids in blood by UPLC–MRM–IDA–EPI: Application to poisoning case

Toxic alkaloids are typically found in herbal medicines and have strong pharmacological effects and a broad therapeutic spectrum. On the other hand, toxic alkaloids exert toxicological activities in vivo; as such they have a narrow therapeutic window and can induce poisoning due to incorrect dose or misuse. In this view, there is an urgent need to develop a rapid and sensitive assay to detect these toxic alkaloids. This study developed a method for determining five common toxic alkaloids in blood, including brucine, strychnine, aconitine, mesaconitine, and hypaconitine using ultra-high liquid chromatography-tandem quadrupole/linear ion trap mass spectrometry (QTRAP UPLC–MS/MS). The analytes in this investigation were extracted with ether and detected using multiple reaction monitoring (MRM)-information-dependent acquisition (IDA)-enhanced product ion (EPI) scanning modes. SKF525A served as the internal standard (IS). The approach demonstrated excellent linearity, with a correlation coefficient (R) > 0.9964, and satisfactory sensitivity, with the limit of detection (LOD) of 0.31 ∼ 3.26 ng/mL and a limit of quantification (LOQ) of 1.13 ∼ 11.52 ng/mL. The extraction recovery (ER) was 78.8 ∼ 116.2%, the matrix effect (ME) was −12.3 ∼ 21.2%, and the method accuracy was 0.8 ∼ 12.8%. In addition, the intra-day precision and the inter-day precision (RSD) were 0.7% ∼ 7.4% and 0.4% ∼ 13.5%, respectively. The developed approach is sensitive and efficient, and offer significant application prospect in clinical monitoring and forensic detection of poisoning.

Technical comparison of continuous versus intermittent perfusion computed tomography computed tomography scans of the human pancreas.

Pancreatic perfusion computed tomography (CT) imaging is increasingly used for neoplastic grading, predicting prognosis, and evaluating the response to therapy. To optimize the clinical pancreatic CT perfusion imaging methods, we evaluated 2 different CT scanning protocols concerning pancreas perfusion parameters. A retrospective study was conducted on 40 patients who underwent whole pancreas CT perfusion scanning in The First Affiliated Hospital of Zhengzhou University. Of these 40 patients, 20 patients in group A underwent continuous perfusion scanning, while 20 patients in group B underwent intermittent perfusion scanning. For group A, continuous axial scanning was performed 25 times, and the total scan time was 50 s. For group B, arterial phase helical perfusion scanning was performed 8 times, and then venous phase helical perfusion scanning was performed 15 times, with a total scan time of 64.6 to 70.0 s. A comprehensive list of perfusion parameters between different parts of the pancreas and the 2 groups were compared. The effective radiation dose for the 2 scanning methods was analyzed. The parameter of the mean slope of increase (MSI) at different pancreatic parts in group A differed (P=0.028). The pancreas head had the lowest value, and the tail had the highest (about a 20% difference). In group A compared to group B, the blood volume of the pancreatic head was smaller (15.256±2.925 vs. 16.953±3.602), the positive enhanced integral was smaller (0.307±0.050 vs. 0.344±0.060) and the permeability surface was larger (34.205±9. 612 vs. 24.377±8.413); the blood volume of the pancreatic neck was smaller (13.940±2.691 vs. 17.173±3.918), the positive enhanced integral was smaller (0.304±0.088 vs. 0.361±0.051) and the permeability surface was larger (34.898±11.592 vs. 25. 794±8.149); the blood volume of the pancreatic body was smaller (16.142±4.006 vs. 18.401±2.513), the positive enhanced integral was smaller (0.305±0.093 vs. 0.342±0.048) and the permeability surface was larger (28.861±10.448 vs. 22.158±6. 017); the blood volume of the pancreatic tail was smaller (16.446±3.709 vs. 17.374±3.781), the positive enhanced integral was smaller (0.304±0.057 vs. 0.350±0.073) and the permeability surface was larger (27.823±8.228 vs. 21.509±7.768) (P<0.05). The effective radiation dose in the intermittent scan mode was slightly lower at 16.657±2.259 mSv than in the continuous scan mode (17.973±3.698 mSv). Different CT scanning intervals had a significant influence on whole pancreas blood volume, permeability surface, and positive enhanced integral. These demonstrate the high sensitivity of intermittent perfusion scanning for identifying perfusion abnormalities. Therefore, for the diagnosis of pancreatic diseases, intermittent pancreatic CT perfusion may be more advantageous.

A Low-Cost Burn-In Tester Architecture to Supply Effective Electrical Stress

Burn-In test equipment usually owns extensive memory capabilities to store pre-computed patterns to be applied to the circuit inputs as well as ad-hoc circuitries to drive and read the DUT pins during the BI phase. The solution proposed in this paper dramatically reduces the memory size requirement and just demands a generic microcontroller unit (MCU) equipped with a couple of embedded processors, some standard common peripheral units, and a few KB memories. Moreover, the proposed Burn-In tester could be integrated into a System Level Test equipment which is typically based on MCUs to communicate functionally with the DUT. This paper provides full details about the architecture of such a low-cost innovative tester, which can supply the DUT with unlimited pseudo-random patterns created autonomously by the MCU firmware from any selected seed. The tester prototype developed to collect experimental results includes a low-cost System-on-Chip based on a multi-core MCU and a set of peripheral cores, encompassing timers and Direct Memory Access modules. The tester prototype is used to stress an automotive chip accounting for about 20 million gates, 700 thousand scan flip-flops, and several scan modes. The combination of pseudo-random pattern generation with the ability to control different scan and Design for Testability (DfT) modes, including LBIST, permits to reach a higher coverage of stress metrics than by the application of a limited set of pre-computed ATPG patterns. The toggle coverage level reached is up to 95.89&#x0025;. The application speed achieved by the tester with non-optimized connections is up to about 10MHz.

A Hybrid FDK (H-FDK) Algorithm for Circular Cone-beam CT that Combines Variable Filtering and Conjugate Rays

Circular cone-beam computed tomography (CT) is a popular configuration in industrial non-destructive testing. Corresponding to the circular cone-beam CT, the Feldkamp, Davis, and Kress (FDK) algorithm is the most popular reconstruction method. However, in the case of large cone angle scanning, the slice artifacts of the reconstruction using the FDK algorithm are visible because the data collected with the circular orbit scan mode do not satisfy the completeness conditions for exact reconstruction. To solve the problem, this study proposed a hybrid FDK (H-FDK) algorithm using a method that combines variable filtering and conjugate rays. First, the shape and curvature of the detector were changed for the filtering paths to be variable. Then, the conjugate weighting function for backprojection was constructed. Subsequently, optimization experiments were conducted to find optimal parameters for the detector and conjugate weighting function. Finally, the comparative experimental results demonstrated that the slices reconstructed by the H-FDK algorithm produced a discernible quality improvement.

Fast Scan mode of scanning electrochemical microscopy: In-situ characterization of phase transition and mapping the hydrogen evolution activity for MoS2

Fast Scan mode of scanning electrochemical microscopy: In-situ characterization of phase transition and mapping the hydrogen evolution activity for MoS2

Improving image quality and resolution of coronary arteries in coronary computed tomography angiography by using high-definition scans and deep learning image reconstruction.

Coronary computed tomography angiography (CTA) has been increasingly used to identify the degree of coronary artery stenosis and plaque lesions in vessels. This study evaluated the feasibility of using high-definition (HD) scanning with high-level deep learning image reconstruction (DLIR-H) to improve the image quality and spatial resolution when imaging calcified plaques and stents in coronary CTA as compared to the standard definition (SD) reconstruction mode with adaptive statistical iterative reconstruction-V (ASIR-V). A total of 34 patients (age 63.3±10.9 years; 55.88% female) with calcified plaques and/or stents who underwent coronary CTA in HD-mode were included in this study. Images were reconstructed with SD-ASIR-V, HD-ASIR-V, and HD-DLIR-H. Subjective image quality with image noise and clarity of vessels, calcifications, and stented lumens was evaluated by 2 radiologists using a 5-point scale. The kappa (κ) test was used to analyze the interobserver agreement. Objective image quality with image noise, signal-to-noise-ratio (SNR), and contrast-to-noise-ratio (CNR) was measured and compared. Image spatial resolution and beam-hardening artifacts (BHAs) were also evaluated using the calcification diameter and CT numbers in 3 points along the stented lumen (inside, at the proximal and distal ends just outside stent). There were 45 calcified plaques and 4 coronary stents. HD-DLIR-H images had the highest overall image quality score (4.50±0.63) with the lowest image noise (22.59±3.59 HU) and the highest SNR (18.30±4.88) and CNR (26.56±6.33), followed by SD-ASIR-V50% image quality score (4.06±2.49), image noise (35.02±8.09 HU), SNR (12.77±1.59), CNR(15.67±1.92) and HD-ASIR-V50% image quality score (3.90±0.64), image noise (57.7±12.03 HU), SNR (8.16±1.86), CNR (10.01±2.39). HD-DLIR-H images also had the smallest calcification diameter measurement (2.36±1.58 mm), followed by HD-ASIR-V50% (3.46±2.07 mm) and SD-ASIR-V50% (4.06±2.49 mm). HD-DLIR-H images had the closest CT value measurements for the 3 points along the stented lumen, indicating much less BHA. Interobserver agreement on the image quality assessment was good to excellent (HD-DLIR-H: κ value =0.783; HD-ASIR-V50%: κ value =0.789; SD-ASIR-V50%: κ value =0.671). Coronary CTA with HD scan mode and DLIR-H significantly improves the spatial resolution for displaying calcifications and in-stent lumens while simultaneously reducing image noise.