Scanning Area Research Articles

Impact of Adsorption of Rare-Earth Elements on the Structure and Magnetic Parameters of Nanostructured Ceramic Oxides Containing Mg Nano Spinel Ferrite

This study focuses on the characterization and synthesis of ceramic materials that have magnetic nanoparticles (MgFe2O4) within an insulating (wüstite or magnesiowüstite) matrix (Mg1-xFexO). Ceramic Oxides were employed to absorb and elute rare-earth elements (REEs). Elements were carried out in experimental batches, including the effect of pH, adsorbent dose initial REE ions concentration, and equilibrium time. The Langmuir isotherm with a monolayer adsorption capacity surpassed 397 mg g−1 at room temperature. REE ions were effectively eluted from loaded Ceramic Oxides nanoparticles with 0.1 mol l−1 of HCl acid with an efficiency of 98%. Equilibrium modeling presented the Freundlich isotherm as the best fit model for both adsorbents and metal ions, indicating heterogeneity of the surface binding sites during adsorption. The pseudo-first order kinetic model was the best-fit model. Different qualitative techniques are used to emphasis the adsorption of REE ions onto Ceramic Oxides nanoparticles. The effect of REEs ions adsorption on the structural and morphological properties have been investigated using X-ray diffraction (XRD), porosity & surface area scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The functional groups were detected by Fourier Transform infrared spectroscopy (FTIR). By applying a magnetic field of ±20 kOe, using vibrating sample magnetometer (VSM), (M-H) hysteresis loops were formed. The difference in ionic radius and atomic weight of the REE ions is highly renovated to the fluctuations in crystallographic and magnetic parameters. Finally, Ceramic Oxides nanoparticles possessed good adsorption properties such as stability and reusability, which have potential application in wastewater treatment.

Symmetry of Macular Fundus Features in Age-Related Macular Degeneration

The symmetry of major macular fundus features in both eyes of the same patient with age-related macular degeneration (AMD) was investigated using swept-source(SS)-OCT. Retrospective review of a prospective study. Patients with AMD. Grading was performed on the first SS-OCT images obtained on the patients. Two graders diagnosed the presence of drusen, geographic atrophy (GA), and exudative AMD (eAMD) in each eye. Medical records were reviewed to assess prior exudation. To assess symmetry, 1 eye of each patient was randomly selected as the index eye and compared with the fellow eye. The kappa statistic (κ) was used to assess the symmetry of diagnosis. The intraclass correlation coefficient (ICC) was used to assess the symmetry of drusen area and volume. Interocular symmetry of the AMD stages: drusen, GA, and eAMD. A total of 1310 patients with AMD were included. The average age was 78 years (range, 50-102; 60% women). Of the 1310 subjects, 54% (701) presented with symmetric disease: 20% with bilateral drusen, 11% with bilateral GA, and 22% with bilateral eAMD. Only 0.5% of the subjects had both GA and eAMD in both eyes. Of the randomly selected index eyes, 825 (47%) were right eyes. Overall, limited interocular agreement was observed between the index and fellow eyes (54%; κ= 0.29). Kappa coefficients were poor (< 0.4) for index eyes diagnosed with drusen (κ= 0.27), eAMD (κ= 0.17), and mixed disease (κ= 0.03). There was moderate agreement between the index and fellow eyes for GA (κ= 0.50). Of the 265 patients with bilateral drusen, the symmetry of drusen area measurements had moderate ICC values of 0.70, 0.71, and 0.70 in the 3- and 5-mm diameter foveal-centered circles and in the total scan area, respectively. The ICC values for the drusen volumes were 0.65, 0.66, and 0.64, respectively. Interocular symmetry was poor for eyes with drusen, eAMD, and mixed disease, but moderate for GA. Although the diagnosis of drusen was not very symmetric between eyes, when present in both eyes, the drusen area and volume measurements were moderately symmetric. Proprietary or commercial disclosure may be found after the references.

Analysis of spatial–temporal dynamic distribution and related factors of tuberculosis in China from 2008 to 2018

Through spatial–temporal scanning statistics, the spatial–temporal dynamic distribution of pulmonary tuberculosis incidence in 31 provinces and autonomous regions of China from 2008 to 2018 is obtained, and the related factors of spatial–temporal aggregation of tuberculosis in China are analyzed to provide strong scientific basis and data support for the prevention and control of pulmonary tuberculosis. This is a retrospective study, using spatial epidemiological methods to reveal the spatial–temporal clustering distribution characteristics of China's tuberculosis epidemic from 2008 to 2018, in which cases data comes from the China Center for Disease Control and prevention. Office Excel is used for general statistical description, and the single factor correlation analysis adopts χ2 Test (or trend χ2 Inspection). Retrospective discrete Poisson distribution space time scanning statistics of SaTScan 9.6 software are used to analyze the space time dynamic distribution of tuberculosis incidence in 31 provinces, cities and autonomous regions in China from 2008 to 2018. ArcGIS 10.2 software is used to visualize the results. The global spatial autocorrelation analysis adopts Moran's I of ArcGIS Map(Monte Carlo randomization simulation times of 999) is used to analyze high-risk areas, low-risk areas and high-low risk areas. From 2008 to 2018, 10,295,212 cases of pulmonary tuberculosis were reported in China, with an average annual incidence rate of 69.29/100,000 (95% CI: (69.29 ± 9.16)/100,000). The annual GDP (gross domestic product) of each province and city showed an upward trend year by year, and the number of annual medical institutions in each province and city showed a sharp increase in 2009, and then tended to be stable; From 2008 to 2018, the national spatiotemporal scanning statistics scanned a total of 6 clusters, including 23 provinces and cities. The national high-low spatiotemporal scanning statistics of the number of pulmonary tuberculosis cases scanned a total of 2 high-risk and low-risk clusters. The high-risk cluster included 8 provinces and cities, and the low-risk cluster included 12 provinces and cities. The global autocorrelation Moran's I index of the incidence rate of pulmonary tuberculosis in all provinces and cities was greater than the expected value (E (I) = −0.0333); The correlation analysis between the average annual GDP and the number of pulmonary tuberculosis cases in each province and city from 2008 to 2018 was statistically significant. From 2008 to 2018, the spatial and temporal scanning and statistical scanning areas of tuberculosis incidence in China were mainly concentrated in the northwest and southern regions of China. There is an obvious positive spatial correlation between the annual GDP distribution of each province and city, and the aggregation degree of the development level of each province and city is increasing year by year. There is a correlation between the average annual GDP of each province and the number of tuberculosis cases in the cluster area. There is no correlation between the number of medical institutions set up in each province and city and the number of pulmonary tuberculosis cases.

Preoperative simulation results and intraoperative image fusion guidance for transjugular intrahepatic portosystemic shunt placement: a feasibility study of nineteen patients.

The purpose is to evaluate the feasibility and efficacy of preoperative simulation results and intraoperative image fusion guidance during transjugular intrahepatic portosystemic shunt (TIPS) creation. Nineteen patients were enrolled in the present study. The three-dimensional (3D) structures of the bone, liver, portal vein, inferior vena cava, and hepatic vein in the contrast-enhanced computed tomography (CT) scanning area were reconstructed in the Mimics software. The virtual Rosch-Uchida liver access set and the VIATORR stent model were established in the 3D Max software. The puncture path from the hepatic vein to the portal vein and the release position of the stent were simulated in the Mimics and 3D Max software, respectively. The simulation results were exported to Photoshop software, and the 3D reconstructed top of the liver diaphragm was used as the registration point to fuse with the liver diaphragmatic surface of the intraoperative fluoroscopy image. The selected portal vein system fusion image was overlaid on the reference display screen to provide image guidance during the operation. As a control, the last 19 consecutive cases of portal vein puncture under the guidance of conventional fluoroscopy were analyzed retrospectively, including the number of puncture attempts, puncture time, total procedure time, total fluoroscopy time, and total exposure dose (dose area product). The average time of preoperative simulation was about 61.26 ± 6.98 minutes. The average time of intraoperative image fusion was 6.05 ± 1.13 minutes. The median number of puncture attempts was not significantly different between the study group (n = 3) and the control group (n = 3; P = 0.175). The mean puncture time in the study group (17.74 ± 12.78 min) was significantly lower than that in the control group (58.32 ± 47.11 min; P = 0.002). The mean total fluoroscopy time was not significantly different between the study group (26.63 ± 12.84 min) and the control group (40.00 ± 23.44 min; P = 0.083). The mean total procedure time was significantly lower in the study group (79.74 ± 37.39 min) compared with the control group (121.70 ± 62.24 min; P = 0.019). The dose area product of the study group (220.60 ± 128.4 Gy. cm2) was not significantly different from that of the control group (228.5 ± 137.3 Gy. cm2; P = 0.773). There were no image guidance-related complications. The use of preoperative simulation results and intraoperative image fusion to guide a portal vein puncture is feasible, safe, and effective when creating a TIPS. The method is cheap and may improve portal vein puncture, which may be valuable for hospitals lacking intravascular ultrasound and digital subtraction angiography (DSA) equipment equipped with a CT-angiography function.

A Freehand 3D Ultrasound Reconstruction Method Based on Deep Learning

In the medical field, 3D ultrasound reconstruction can visualize the internal structure of patients, which is very important for doctors to carry out correct analyses and diagnoses. Furthermore, medical 3D ultrasound images have been widely used in clinical disease diagnosis because they can more intuitively display the characteristics and spatial location information of the target. The traditional way to obtain 3D ultrasonic images is to use a 3D ultrasonic probe directly. Although freehand 3D ultrasound reconstruction is still in the research stage, a lot of research has recently been conducted on the freehand ultrasound reconstruction method based on wireless ultrasonic probe. In this paper, a wireless linear array probe is used to build a freehand acousto-optic positioning 3D ultrasonic imaging system. B-scan is considered the brightness scan. It is used for producing a 2D cross-section of the eye and its orbit. This system is used to collect and construct multiple 2D B-scans datasets for experiments. According to the experimental results, a freehand 3D ultrasonic reconstruction method based on depth learning is proposed, which is called sequence prediction reconstruction based on acoustic optical localization (SPRAO). SPRAO is an ultrasound reconstruction system which cannot be put into medical clinical use now. Compared with 3D reconstruction using a 3D ultrasound probe, SPRAO not only has a controllable scanning area, but also has a low cost. SPRAO solves some of the problems in the existing algorithms. Firstly, a 60 frames per second (FPS) B-scan sequence can be synthesized using a 12 FPS wireless ultrasonic probe through 2–3 acquisitions. It not only effectively reduces the requirement for the output frame rate of the ultrasonic probe, but also increases the moving speed of the wireless probe. Secondly, SPRAO analyzes the B-scans through speckle decorrelation to calibrate the acousto-optic auxiliary positioning information, while other algorithms have no solution to the cumulative error of the external auxiliary positioning device. Finally, long short-term memory (LSTM) is used to predict the spatial position and attitude of B-scans, and the calculation of pose deviation and speckle decorrelation is integrated into a 3D convolutional neural network (3DCNN). Prepare for real-time 3D reconstruction under the premise of accurate spatial pose of B-scans. At the end of this paper, SPRAO is compared with linear motion, IMU, speckle decorrelation, CNN and other methods. From the experimental results, it can be observed that the spatial pose deviation of B-scans output using SPRAO is the best of these methods.

. The moderated ct angiography of the heart scanning protocol for children with dilated cardiomyopathy

Purpose. To moderate computed tomography angiography (CTA) of the heart scanning protocol in children with dilated cardiomyopathy and low left ventricle ejection fraction (LVEF) for optimal visualization of the heart and its major vessels.Materials and methods. We examined 38 patients aged from 9 months to 17 years, undergoing treatment at the cardiology department in the of the Rehabilitation Clinic for Children of the Almazov National Medical Research Centre. Firstly, all patients were performed echocardiography (Echo). Echo data evaluated LVEF. The patients were selected based on the clinical diagnosis, the LVEF index, the patient’s height (or the length of the scan area). 2 groups of patients with DCM (with low LVEF) were formed - younger and older patients; for each group was formed a control group of patients with normal LVEF values. All patients underwent CTA on a 128-sliced computed tomograph Ingenuity Elite (Philips, Netherlands) after a bolus intravenous contrast medium injection.Results. There was revealed a relationship between the start time of the scan and the LVEF, the patient’s height. For patients with low LVEF were created study protocols, where scan start time offset was set as: for the group 1 in the early arterial phase +3c, in the late arterial phase +5c, in the venous phase +15c; for the group 2 in the early arterial phase +5c, in the late arterial phase +5c, in the venous phase +29c.Conclusion. The moderated scanning protocol presents good contrast enhancement by chambers of the heart and its major vessels. It is necessary for an assessment of the anatomy and pathological changes. The identified criteria (LVEF, patient height) should be considered for CTA of the heart in children with dilated cardiomyopathy.

A study on characteristic indexes of railway ballast bed under high-frequency radar

PurposeIn this paper, a high-frequency radar test system was used to collect the data of clean ballast bed and fouled ballast bed of ballasted tracks, respectively, for a quantitative evaluation of the condition of railway ballast bed.Design/methodology/approachBased on original radar signals, the time–frequency characteristics of radar signals were analyzed, five ballast bed condition characteristic indexes were proposed, including the frequency domain integral area, scanning area, number of intersections with the time axis, number of time-domain inflection points and amplitude envelope obtained by Hilbert transform, and the effectiveness and sensitivity of the indexes were analyzed.FindingsThe thickness of ballast bed tested at the sleep bottom by high-frequency radar is up to 55 cm, which meets the requirements of ballast bed detection. Compared with clean ballast bed, the values of the five indexes of fouled ballast bed are larger, and the five indexes could effectively show the condition of the ballast bed. The computational efficiency of amplitude envelope obtained by Hilbert transform is 140 s·km−1, and the computational efficiency of other indexes is 5 s·km−1. The amplitude envelopes obtained by Hilbert transform in the subgrade sections and tunnel sections are the most sensitive, followed by scanning area. The number of intersections with the time axis in the bridge sections was the most sensitive, followed by the scanning area. The scanning area can adapt to different substructures such as subgrade, bridges and tunnels, with high comprehensive sensitivity.Originality/valueThe research can provide appropriate characteristic indexes from the high-frequency radar original signal to quantitatively evaluate ballast bed condition under different substructures.

Noncontact sensing for water area scanning identification based on Ho2O3/GO humidity sensor

With the advent of the era of intelligent perception and artificial intelligence, higher requirements on the response/recovery speed of humidity sensitive materials and the expansion of new applications of humidity sensors have been put forward. In this study, Ho2O3/GO composites were obtained by ultrasonic stirring of the GO solution with the synthesized Ho2O3 material. Benefiting from the presence of adsorbed hydroxyl oxygen on the surface and the regular arrangement of the nanosheets, the humidity response of Ho2O3/GO sensor has nearly doubled from 1102 to 2136, and the recovery time was reduced by more than half from 6 s to 1 s. Based on excellent humidity sensitive properties, the sensor was used for non-contact scanning to identify water zones of different shapes, thus presenting information on the distribution of water beneath the sensor. This research opens up further possibilities for the expansion of humidity sensors in emerging applications such as smart sensing.

Different Ultrasound Shear Wave Elastography Techniques as Novel Imaging-Based Approaches for Quantitative Evaluation of Hepatic Steatosis—Preliminary Findings

Modern ultrasound (US) shear-wave dispersion (SWD) and attenuation imaging (ATI) can be used to quantify changes in the viscosity and signal attenuation of the liver parenchyma, which are altered in hepatic steatosis. We aimed to evaluate modern shear-wave elastography (SWE), SWD and ATI for the assessment of hepatic steatosis. We retrospectively analyzed the US data of 15 patients who underwent liver USs and MRIs for the evaluation of parenchymal disease/liver lesions. The USs were performed using a multifrequency convex probe (1-8 MHz). The quantitative US measurements for the SWE (m/s/kPa), the SWD (kPa-m/s/kHz) and the ATI (dB/cm/MHz) were acquired after the mean value of five regions of interest (ROIs) was calculated. The liver MRI (3T) quantification of hepatic steatosis was performed by acquiring proton density fat fraction (PDFF) mapping sequences and placing five ROIs in artifact-free areas of the PDFF scan, measuring the fat-signal fraction. We correlated the SWE, SWD and ATI measurements to the PDFF results. Three patients showed mild steatosis, one showed moderate steatosis and eleven showed no steatosis in the PDFF sequences. The calculated SWE cut-off (2.5 m/s, 20.4 kPa) value identified 3/4 of patients correctly (AUC = 0.73, p > 0.05). The SWD cut-off of 18.5 m/s/kHz, which had a significant correlation (r = 0.55, p = 0.034) with the PDFF results (AUC = 0.73), identified four patients correctly (p < 0.001). The ideal ATI (AUC = 0.53 (p < 0.05)) cut-off was 0.59 dB/cm/MHz, which showed a significantly good correlation with the PDFF results (p = 0.024). Hepatic steatosis can be accurately detected using all the US-elastography techniques applied in this study, although the SWD and the SWE showed to be more sensitive than the PDFF.

Carum carvi mediated green synthesis of copper nanoparticles and its effect on Solanum lycopersicum seedlings

The present study aims to synthesis the copper nanoparticles (CuNPs) and their effect on the biochemical and physiological characteristics of Solanum lycopersicum. The results exhibited the color change in the Carum carvi aqueous extract from clear deep brown to a greenish color and this observation indicated the green-biosynthesis of CuNPs by reduction of Cu+ to Cu0. Also, the absorbance broadening band for the green-biosynthetic CuNPs appeared at the 340 nm wavelength using UV-Vis but the C. carvi aqueous extract not showed any peaks at this wavelength. SEM analysis exhibited the micrographic surface morphology and the shape of the green-biosynthetic CuNPs with a scan area of 50 μm and showed the spherical shape particles of CuNPs aggregation. The three-dimensional image and the surface morphology of green-biosynthesized CuNPs and C. carvi aqueous extract were examined using AFM analysis that showed the surface of C. carvi aqueous extract was 45.5 nm size with non-homologus and irregular form of distribution, but the green-biosynthesized CuNPs were 12.4 nm size in nanoscale with regular and homogenous distribution form. The results also showed that the effect of bio-synthesized copper nanoparticles was evident on the S. lycopersicum seedlings fresh and dry weight according to the different reading times after treatment with nanoparticles. Also, the concentration of 2.5 mg/mL (CuNPs) showed a significant increase in the chlorophyll content (58.51 μg/cm²) on the 21st day after treatment and a significant increase in the activity of peroxidase enzyme (35.12 U min-1 mg-1 protein) was obtained at the concentration of 2.5 mg/mL (CuNPs) at 21st day after germination.

Micro-mechanisms of deformation accommodation in AA7050 alloy in the presence of hydrogen

The interaction of hydrogen with dislocations in AA 7050 alloy heat treated to produce different matrix precipitates is studied using interrupted micro-tensile tests of pre-charged specimens and electron back scattered diffraction (EBSD). Hydrogen promoted slip planarity as well as sub-grain formation in the overaged condition having incoherent ƞ (MgZn2) precipitates, while it enhanced dislocation looping and pitting in case of higher density Mg-Zn precipitates (GP II) dominated alloy. For the first time, a semi-quantitative analysis on the extent of the effect of hydrogen on micro-mechanisms of deformation evolution is carried out using sufficient statistics through large area scans in EBSD. It is shown that the interaction of pre-charged hydrogen with the microstructure was unaffected by recrystallization as well as texture till 6% strain.

The experience of auditory implant recipients undergoing magnetic resonance imaging: Factors associated with pain

Objective Many patients with cochlear implants (CI) and auditory brainstem implants (ABI) require magnetic resonance imaging (MRI) following implantation. This study explores the patient experience of MRI, identifying factors associated with pain, and the effect of interventions designed to enhance comfort and safety. Methods A prospective observational case series from a tertiary referral unit. Tight head bandaging ± local anaesthetic injection (devices with non-MRI-compatible magnets) or observation alone (implants with MRI-compatible magnets) were employed for 1.5 T MRI of consecutive adult patients with CI or ABI without magnet removal. Pain was recorded via visual analogue scale (1 = no pain, 5 = extreme pain) at three time points; (1) baseline, (2) head bandage applied (3) during scanning. Patient age, device type, body area imaged and total scan time were recorded as variables, alongside adverse events. Results Data were collected for 227 MRI scans (34 patients with ABI, 32 with CI). In patients managed with bandaging, pain score after bandaging but prior to scanning (median 2.2) did not differ from pain during scanning (2.1), but both were significantly higher than baseline (1.4, both P ≤ 0.001). Scanning areas other than the head/cervical spine was associated with higher pain scores (P = 0.036). Pain during MRI differed between different manufacturers implants (P ≤ 0.001). Adverse events occurred in 8/227 scans (3.5%), none occurring with devices containing an MRI-compatible magnet. Conclusion MRI scanning with auditory implant magnets in situ is safe and well tolerated by patients.

Scanning accuracy and scanning area discrepancies of intraoral digital scans acquired at varying scanning distances and angulations among 4 different intraoral scanners

Statement of problemThe accuracy of intraoral scanners (IOSs) can be affected by operator handling; however, the scanning area and accuracy discrepancies acquired at different scanning distances and angulations among IOSs remain uncertain. PurposeThe objective of this in vitro study was to compare the scanning area and scanning accuracy of the intraoral digital scans obtained at 3 scanning distances with 4 different scanning angulations among 4 different IOSs. Material and methodsA reference device (reference file) was designed with 4 inclinations (0, 15, 30, and 45 degrees) and printed. Four groups were created based on the IOS: i700, TRIOS4, CS 3800, and iTero scanners. Four subgroups were generated depending on the scanning angulation (0, 15, 30, and 45 degrees). Each subgroup was divided into 3 subgroups based on the scanning distance: 0, 2, and 4 mm (N=720, n=15). The reference devices were positioned in a z-axis calibrated platform for standardizing the scanning distance. In the i700-0-0 subgroup, the 0-degree reference device was positioned in the calibrated platform. The wand of the IOS was positioned in a supporting framework with a 0-mm scanning distance, and the scans were acquired. In the i700-0-2 subgroup, the platform was lowered for a 2-mm scanning distance followed by the specimen acquisition. In the i700-0-4 subgroup, the platform was further lowered for a 4-mm scanning distance, and the scans were obtained. For the i700-15, i700-30, and i700-45 subgroups, the same procedures were carried out as in the i700-0 subgroups respectively, but with the 10-, 15-, 30-, or 45-degree reference device. Similarly, the same procedures were completed for all the groups with the corresponding IOS. The area of each scan was measured. The reference file was used to measure the discrepancy with the experimental scans by using the root mean square (RMS) error. Three-way ANOVA and post hoc Tukey pairwise comparison tests were used to analyze the scanning area data. Kruskal–Wallis and multiple pairwise comparison tests were used to analyze the RMS data (α=.05). ResultsIOS (P<.001), scanning distance (P<.001), and scanning angle (P<.001) were significant factors of the scanning area measured among the subgroups tested. A significant group×subgroup interaction was found (P<.001). The iTero and the TRIOS4 groups obtained higher scanning area mean values than the i700 and CS 3800 groups. The CS 3800 obtained the lowest scanning area among the IOS groups tested. The 0-mm subgroups obtained a significantly lower scanning area than the 2- and 4-mm subgroups (P<.001). The 0- and 30-degree subgroups obtained a significantly lower scanning area than the 15- and 45-degree subgroups (P<.001). The Kruskal–Wallis test revealed significant median RMS discrepancies (P<.001). All the IOS groups were significantly different from each other (P<.001), except for the CS 3800 and TRIOS4 groups (P>.999). All the scanning distance groups were different from each other (P<.001). ConclusionsScanning area and scanning accuracy were influenced by the IOS, scanning distance, and scanning angle selected to acquire the digital scans.

Visual application of navigation framework in cyber-physical system for mobile robot to prevent disease

In this article, we propose the visual application of a navigation framework for a wheeled robot to disinfect surfaces. Since dynamic environments are complicated, advanced sensors are integrated into the hardware platform to enhance the navigation task. The 2D lidar UTM-30LX from Hokuyo attached to the front of the robot can cover a wide scanning area. To provide better results in laser scan matching, an inertial measurement unit was integrated into the robot’s body. The output of this combination feeds into a global costmap for monitoring and navigation. Additionally, incremental encoders that obtain high-resolution position data are connected to the rear wheels. The role of the positioning sensor is to identify the existing location of the robot in a local costmap. To detect the appearance of a human, a Kinect digital camera is fixed to the top of the robot. All feedback signals are combined in the host computer to navigate the autonomous robot. For disinfection missions, the robot must carry several ultraviolet lamps to autonomously patrol in unknown environments. To visualize the robot’s effectiveness, our approach was validated using both a virtual simulation and an experimental test. The contributions of this work are summarized as follows: (i) a structure for ultraviolet-based hardware was first established; (ii) the theoretical computations for the robot’s localization in the 3D workspace will play a fundamental role in further developments; and (iii) data fusion from advanced sensing devices was integrated to enable navigation in uncertain environments.

Self-calibration of terrestrial laser scanner using a M3C2-based planar patch algorithm

Target- or intensity-feature-based calibration has been extensively explored for in-situ calibration of terrestrial laser scanners (TLSs). Those calibration approaches main drawbacks include the necessity of mounting physical targets in the scan area and the need for the presence of rich geometrical features allowing a feature-based distinction of different points in the point cloud. We propose an autonomous TLS calibration algorithm using planar patches that are ubiquitous in urban environments and can be found without manual preparation beforehand. The scanner calibration parameters are estimated and updated by minimizing the M3C2 normal distances between corresponding planar patches. Unlike target- or keypoint-based approaches, only medium-resolution scan data is needed. A comprehensive set of calibration model parameters are estimated using scans acquired from multiple positions, thereby providing a further advantage over current keypoint-based approaches that estimate only two-face sensitive parameters. To increase speed and reduce memory consumption, we propose to execute the calibration using only parts of scan data from a single station. Studies with two high-precision scanners, Leica RTC360 and Z+F Imager 5016, show results consistent with the laborious target-based approach with improved precision. Similar two-face sensitive calibration performance to the target- and keypoint-based approaches has been achieved, but with only subsets of the point cloud using the proposed algorithm.

Compact and low-cost deep-ultraviolet microscope system for label-free molecular imaging and point-of-care hematological analysis.

Deep-ultraviolet (UV) microscopy enables label-free, high-resolution, quantitative molecular imaging and enables unique applications in biomedicine, including the potential for fast hematological analysis at the point-of-care. UV microscopy has been shown to quantify hemoglobin content and white blood cells (five-part differential), providing a simple alternative to the current gold standard, the hematological analyzer. Previously, however, the UV system comprised a bulky broadband laser-driven plasma light source along with a large and expensive camera and 3D translation stage. Here, we present a modified deep-UV microscope system with a compact footprint and low-cost components. We detail the novel design with simple, inexpensive optics and hardware to enable fast and accurate automated imaging. We characterize the system, including a modified low-cost web-camera and custom automated 3D translation stage, and demonstrate its ability to scan and capture large area images. We further demonstrate the capability of the system by imaging and analyzing blood smears, using previously trained networks for automatic segmentation, classification (including 5-part white blood cell differential), and colorization. The developed system is approximately 10 times less expensive than previous configurations and can serve as a point-of-care hematology analyzer, as well as be applied broadly in biomedicine as a simple compact, low-cost, quantitative molecular imaging system.

Prediction of Early Visual Outcome of Small-Incision Lenticule Extraction (SMILE) Based on Deep Learning.

Deep learning (DL) has been widely used to estimate clinical images. The objective of this project was to create DL models to predict the early postoperative visual acuity after small-incision lenticule extraction (SMILE) surgery. We enrolled three independent patient cohorts (a retrospective cohort and two prospective SMILE cohorts) who underwent the SMILE refractive correction procedure at two different refractive surgery centers from July to September 2022. The medical records and surgical videos were collected for further analysis. Based on the uncorrected visual acuity (UCVA) at 24h postsurgery, the eyes were divided into two groups: those showing good recovery and those showing poor recovery. We then trained a DL model (Resnet50) to predict eyes with early postoperative visual acuity of patients in the retrospective cohort who had undergone SMILE surgery from surgical videos and subsequently validated the model's performance in the two prospective cohorts. Finally, Gradient-weighted Class Activation Mapping (Grad-CAM) was performed for interpretation of the model. Among the 318 eyes (159 patients) enrolled in the study, 10,176 good quality femtosecond laser scanning images were obtained from the surgical videos. We observed that the developed DL model achieved a high accuracy of 96% for image prediction. The area under the curve (AUC) value of the DL model in the retrospective cohort was 0.962 and 0.998 in the training and validation datasets, respectively. The AUC values in two prospective cohorts were 0.959 and 0.936. At the video level, the trained machine learning (ML) model (XGBoost) also accurately distinguished patients with good or poor recovery. The AUC value of the ML model was 0.998 and 0.889 in the retrospective cohort (training and test datasets, respectively) and 1.000 and 0.984 in the two prospective cohorts. We also trained a DL model which can accurately distinguish suction loss (100%), black spots (85%), and opaque bubble layer (96%). The Grad-CAM heatmap indicated that our models can recognize the area of scanning and precisely identify intraoperative complications. Our findings suggest that artificial intelligence (DL and ML model) can accurately predict the early postoperative visual acuity and intraoperative complications after SMILE surgery just using surgical videos or images, which may display a great importance for artificial intelligence in application of refractive surgeries.

A Sector-Matching Probability Hypothesis Density Filter for Radar Multiple Target Tracking

The development of high-tech, dim, small targets, such as drones and cruise missiles, brings great challenges to radar multi-target tracking (MTT), making it necessary to extend the beam dwell time to obtain a high signal-to-noise ratio (SNR). In order to solve the problem of radar sampling time variation exacerbated by extending the beam dwell time when detecting weak targets, a sector-matching (SM) PHD filter is proposed, which combines the actual radar system with a PHD filter and quantifies the relationship between the beam dwell time, the false alarm rate and the detection probability. The proposed filter divides the scanning area into small sectors to obtain actual multi-target measurement times and rederives the prediction and update steps based on the actual sampling time. Furthermore, a state correction step is added before state extraction. Applying the SM structure to the basic Gaussian mixture PHD (GM-PHD) filter and labeled GM-PHD filter, the simulation results demonstrate that the proposed structure can improve the accuracy of multi-weak-target state estimation in the dense clutter and can continuously generate explicit trajectories. The overall real-time performance of the proposed filter is similar to that of the PHD filter.

Facile Control of Ferroelastic Domain Patterns in Multiferroic Thin Films by a Scanning Tip Bias.

BiFeO3, known as the "holy grail of all multiferroics", provides an appealing platform for exploration of multifield coupling physics and design of functional devices. Many fantastic properties of BiFeO3 are regulated by its ferroelastic domain structure. However, a facile programable control on the ferroelastic domain structure in BiFeO3 remains challenging and our understanding on the existing control strategies is also far from complete. This work reports a facile control of ferroelastic domain patterns in BiFeO3 thin films under area scanning poling by exploiting the tip bias as the control parameter. Combining scanning probe microscopy experiments and simulations, we found that BiFeO3 thin films with pristine 71° rhombohedral-phase stripe domains exhibit at least four switching pathways solely by controlling the scanning tip bias. As a result, one can readily write mesoscopic topological defects into the films without the necessity to change the tip motion. The correlation between conductance of the scanned region and the switching pathway is further investigated. Our results extend the current understanding on the domain switching kinetics and the coupled electronic transport properties in BiFeO3 thin films. The facile voltage control of ferroelastic domains should facilitate the development of configurable electronic and spintronic devices.

Localization of low-velocity impact in CFRP plate using time–frequency features of guided wave and convolutional neural network

Carbon fiber reinforced polymer (CFRP) could be damaged by low-velocity impacts. Precise localization of impact can increase the efficiency of nondestructive testing by narrowing the scanning in a small area. The conventional localization method is based on the time-of-arrival (ToA) of impact induced guided wave, whose localization accuracy could be influenced by the reflected waves from plate edges. This paper proposes an impact localization method based on time–frequency features of guided wave and convolutional neural network. To test the algorithm, 585 impact experiments are performed at 117 different locations of a CFRP plate. Signals corresponding to 12 randomly selected locations are treated as test set, and the remaining signals are used for training of the network. The results show that the average localization error of the proposed method is 10.2 mm.