Trial of Endovascular Therapy for Acute Ischemic Stroke with Large Infarct.

BACKGROUND: The role of endovascular therapy for acute stroke with a large infarction has not been extensively studied in differing populations. METHODS: We conducted a multicenter, prospective, open-label, randomized trial in China involving patients with acute large-vessel occlusion in the anterior circulation and an Alberta Stroke Program Early Computed Tomography Score of 3 to 5 (range, 0 to 10, with lower values indicating larger infarction) or an infarct-core volume of 70 to 100 ml. Patients were randomly assigned in a 1:1 ratio within 24 hours from the time they were last known to be well to undergo endovascular therapy and receive medical management or to receive medical management alone. The primary outcome was the score on the modified Rankin scale at 90 days (scores range from 0 to 6, with higher scores indicating greater disability), and the primary objective was to determine whether a shift in the distribution of the scores on the modified Rankin scale at 90 days had occurred between the two groups. Secondary outcomes included scores of 0 to 2 and 0 to 3 on the modified Rankin scale. The primary safety outcome was symptomatic intracranial hemorrhage within 48 hours after randomization. RESULTS: A total of 456 patients were enrolled; 231 were assigned to the endovascular-therapy group and 225 to the medical-management group. Approximately 28% of the patients in both groups received intravenous thrombolysis. The trial was stopped early owing to the efficacy of endovascular therapy after the second interim analysis. At 90 days, a shift in the distribution of scores on the modified Rankin scale toward better outcomes was observed in favor of endovascular therapy over medical management alone (generalized odds ratio, 1.37; 95% confidence interval, 1.11 to 1.69; P = 0.004). Symptomatic intracranial hemorrhage occurred in 14 of 230 patients (6.1%) in the endovascular-therapy group and in 6 of 225 patients (2.7%) in the medical-management group; any intracranial hemorrhage occurred in 113 (49.1%) and 39 (17.3%), respectively. Results for the secondary outcomes generally supported those of the primary analysis. CONCLUSIONS: In a trial conducted in China, patients with large cerebral infarctions had better outcomes with endovascular therapy administered within 24 hours than with medical management alone but had more intracranial hemorrhages. (Funded by Covidien Healthcare International Trading [Shanghai] and others; ANGEL-ASPECT ClinicalTrials.gov number, NCT04551664.).

TRIM29 (Tripartite Motif Containing 29) Alleviates NLRC4 (NLR Family CARD Domain Containing Protein 4) Inflammasome Related Cerebral Injury via Promoting Proteasomal Degradation of NLRC4 in Ischemic Stroke.

BACKGROUND: Neuroinflammation plays extremely crucial roles in the neurological damage mediated by ischemic stroke. TRIM29 (tripartite motif containing 29) has previously been proposed to contribute to the regulation of innate immunity, however, the effect of TRIM29 on ischemic stroke induced neurodegenerative processes and neuroinflammation still largely unexplored. In the current article, we aimed to investigate the function and the precise mechanisms of TRIM29 in ischemic stroke. METHODS: Middle cerebral artery occlusion mice model and oxygen-glucose deprivation cell model were established as in vivo and in vitro models of ischemic stroke. Quantitative real-time polymerase chain reaction (PCR), Western blot, and ELSIA were used to detect the expression levels of TRIM29, cytokines, and marker proteins. Immunofluorescence assay was performed to examine the extent of cell death. Different truncations were generated, and coimmunoprecipitation assays were used to confirm the protein interaction. Ubiquitination assay was performed to detect the ubiquitination levels. RESULTS: We found that the cerebral ischemia-reperfusion induced injury was aggravated in TRIM29 knockout mice after middle cerebral artery occlusion operation as well as the increased neurological deficits score. TRIM29 expression was also found to be up-regulated upon middle cerebral artery occlusion or OGD administration, and loss of TRIM29 promoted the apoptosis and pyroptosis of neurons and microglial cells induced by middle cerebral artery occlusion or OGD, consistent with the enhanced proinflammatory mediators production and activation of NLRC4 (NLR [NOD-like receptor] family CARD [caspase recruitment domain] domain containing protein 4) inflammasome. Furthermore, we observed that TRIM29 interacted with NLRC4 directly and promoted the K48-linked polyubiquitination of NLRC4, lead to the proteasomal degradation of NLRC4. CONCLUSIONS: In conclusion, for the first time, we revealed the role of TRIM29 in ischemic stroke and illustrated the direct relationship between TRIM29 and NLRC4.

Qualitative and Quantitative Assessment of Invasive Surgery Skill Based on a Custom Training Simulator.

PURPOSE: Qualitative and quantitative assessment of interventional performance is a vital component in the evaluation of endovascular surgery skill training. We established a custom simulator with qualitative and quantitative metrics for endovascular performance training. METHODS: The simulator included an in vitro silicone phantom, mock circulation loop, visual module, force-sensing module, and custom software for image and force data postprocessing. Two tasks to deliver the guidewire to the target location of the carotid artery were conducted by the expert (n=4), novice (n=6), and test (n=4) groups. Seven features with significant differences extracted from the expert and novice groups were applied for qualitative assessment using the support vector machine (SVM) and quantitative assessment using the Mahalanobis distance (MD). RESULTS: Significant differences were observed in kinematic and force data between experts and novices during the intervention procedure. The median value of finished time for task 1 was 26.88 seconds for experts and 63.36 seconds for novices. The maximum speed for experts and novices was 32.79 and 7.43 cm/s, respectively. Moreover, the classified results depicted that the accuracy of qualitative assessment for task 1 and task 2 was 96.67% and 90%, respectively. As for the quantitative data, the residents had higher scores than individuals majored in biomedical engineering at 2 tasks (70.06±5.30 vs 41.81±6.58 for task 1, p=0.001). CONCLUSIONS: The proposed endovascular intervention skill training simulator provides qualitative and quantitative metrics on intervention performance skills and may be a useful tool in future interventional surgical training. CLINICAL IMPACT: This simulator comprised an in-vitro silicone phantom, mock circulation loop, visual module, force-sensing module, and custom software for image and force data post-processing. Seven interventional performance features were used for qualitative assessment using the support vector machine and quantitative assessment using the Mahalanobis Distance. From the observations, we conclude that this endovascular intervention skill training simulator provides qualitative and quantitative metrics on intervention performance and may be a useful tool in future surgical training.

miR-19a-3p affected ox-LDL-induced SDC-1/TGF-ß1/Smad3 pathway in atherosclerosis.

Syndecan-1 (SDC-1) was a critical membrane proteoglycan and an important component of the glycocalyx in endothelial cells, but its role in atherosclerosis remains unknown. This study attempted to investigate the role of SDC-1 in atherosclerotic-related endothelial cell injury. Bioinformatics analyzed the differential miRNAs between atherosclerosis and healthy. Subjects with coronary atherosclerosis, which were diagnosed with intravascular atherosclerosis (IVUS), were enrolled as non-vulnerable plaque and vulnerable plaque in Changsha Central Hospital. Human aortic endothelial cells (HAECs) were induced by oxidized low-density lipoprotein (ox-LDL) to construct an in vitro model. A dual luciferase reporter assay was applied to analyze the target between miR-19a-3p and SDC-1. The cell proliferation and apoptosis were detected by CCK8 and flow cytometry, respectively. SDC-1 and cholesterol efflux was determined by ELISA. The expression of ATP-binding cassette (ABC) transports A1 (ABCA1), miR-19a-3p, ABCG1 and SDC-1 genes were detected by RT-qPCR. The expressions of SDC-1, ABCA1, ABCG1, TGF-ß1, Smad3 and p-Smad3 proteins were detected by western blot. Our results found that miR-19a-3p was down-regulated in atherosclerosis. ox-LDL decreased miR-19a-3p expression, increased cholesterol efflux and the expression of ABCA1, ABCG1 and SDC-1 in HAECs. Vulnerable plaque tissues in patients with coronary atherosclerosis showed palpable fibrous necrosis and calcification with elevated blood SDC-1 levels. miR-19a-3p could bind to SDC-1. Overexpression of miR-19a-3p promoted cell proliferation, inhibited apoptosis and cholesterol efflux, down-regulated the expression of SDC-1, ABCA1, ABCG1, TGF-ß1 and p-Smad3 proteins in ox-LDL-induced HAECs. In conclusion, miR-19a-3p targeting SDC-1 inhibited the ox-LDL-induced activation of the TGF-ß1/Smad3 pathway in HAECs.

Conv-TabNet: an efficient adaptive color correction network for smartphone-based urine component analysis.

The camera function of a smartphone can be used to quantitatively detect urine parameters anytime, anywhere. However, the color captured by different cameras in different environments is different. A method for color correction is proposed for a urine test strip image collected using a smartphone. In this method, the color correction model is based on the color information of the urine test strip, as well as the ambient light and camera parameters. Conv-TabNet, which can focus on each feature parameter, was designed to correct the color of the color blocks of the urine test strip. The color correction experiment was carried out in eight light sources on four mobile phones. The experimental results show that the mean absolute error of the new method is as low as 2.8±1.8, and the CIEDE2000 color difference is 1.5±1.5. The corrected color is almost consistent with the standard color by visual evaluation. This method can provide a technology for the quantitative detection of urine test strips anytime and anywhere.

Association of Stroke Subtype With Hemorrhagic Transformation Mediated by Thrombectomy Pass: Data From the ANGEL-ACT Registry.

BACKGROUND: The role of stroke etiology subtype in patients with acute large vessel occlusion on the occurrence of hemorrhagic transformation (HT) after endovascular treatment is poorly studied, and which factors mediate their relationship remains largely unknown. We utilized nationwide registry data to explore the association of stroke subtype (cardioembolism versus large artery atherosclerosis) with HT and to identify the possible mediators. METHODS: A total of 1015 subjects were selected from the ANGEL-ACT registry (Endovascular Treatment Key Technique and Emergency Work Flow Improvement of Acute Ischemic Stroke)-a prospective consecutive cohort of acute large vessel occlusion patients undergoing endovascular treatment at 111 hospitals in China between November 2017 and March 2019-and divided into large artery atherosclerosis (n=538) and cardioembolism (n=477) according to the Trial of ORG 10172 in Acute Stroke Treatment criteria. The types of HT included any intracerebral hemorrhage (ICH), parenchymal hematoma, and symptomatic ICH within 24 hours after endovascular treatment. The association between stroke subtype and HT was analyzed using a logistic regression model. Mediation analysis was done to assess how much of the effect of stroke subtype on HT was mediated through the identified mediators. RESULTS: Stroke subtype (cardioembolism versus large artery atherosclerosis) was associated with increased risk of any ICH (29.8% versus 16.5%; odds ratio, 2.03 [95% CI, 1.22-3.36]), parenchymal hematoma (14.3% versus 5.4%; odds ratio, 2.90 [95% CI, 1.38-6.13]), and symptomatic ICH (9.9% versus 4.7%; odds ratio, 2.59 [95% CI, 1.09-6.16]) after adjustment for potential confounders. The more thrombectomy passes in cardioembolism patients had a significant mediation effect on the association of stroke subtype with increased risk of HT (any ICH, 15.9%; parenchymal hematoma, 13.4%; symptomatic ICH, 14.2%, respectively). CONCLUSIONS: Stroke subtype is an independent risk factor for HT within 24 hours following endovascular treatment among acute large vessel occlusion patients. Mediation analyses propose that stroke subtype contributes to HT partly through thrombectomy pass, suggesting a possible pathomechanistic link. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03370939.

Combined Approach to Eptifibatide and Thrombectomy in Acute Ischemic Stroke Because of Large Vessel Occlusion: A Matched-Control Analysis.

BACKGROUND: In patients undergoing mechanical thrombectomy (MT), adjunctive antithrombotic might improve angiographic reperfusion, reduce the risk of distal emboli and reocclusion but possibly expose patients to a higher intracranial hemorrhage risk. This study evaluated the safety and efficacy of combined MT plus eptifibatide for acute ischemic stroke. METHODS: This was a propensity-matched analysis of data from 2 prospective trials in Chinese populations: the ANGEL-ACT trial (Endovascular Treatment Key Technique and Emergency Workflow Improvement of Acute Ischemic Stroke) in 111 hospitals between November 2017 and March 2019, and the EPOCH trial (Eptifibatide in Endovascular Treatment of Acute Ischemic Stroke) in 15 hospitals between April 2019 and March 2020. The primary efficacy outcome was good outcome (modified Rankin Scale score 0-2) at 3 months. Secondary efficacy outcomes included the distribution of 3-month modified Rankin Scale scores and poor outcome (modified Rankin Scale score 5-6) and successful recanalization. The safety outcomes included any intracranial hemorrhage, symptomatic intracranial hemorrhage, and 3-month mortality. Mixed-effects logistic regression models were used to account for within-hospital clustering in adjusted analyses. RESULTS: Eighty-one combination arm EPOCH subjects were matched with 81 ANGEL-ACT noneptifibatide patients. Compared with the no eptifibatide group, the eptifibatide group had significantly higher rates of successful recanalization (91.3% versus 81.5%; P=0.043) and 3-month good outcomes (53.1% versus 33.3%; P=0.016). No significant difference was found in the remaining outcome measures between the 2 groups. All outcome measures of propensity score matching were consistent with mixed-effects logistic regression models in the total population. CONCLUSIONS: This matched-control study demonstrated that MT combined with eptifibatide did not raise major safety concerns and showed a trend of better efficacy outcomes compared with MT alone. Overall, eptifibatide shows potential as a periprocedural adjunctive antithrombotic therapy when combined with MT. Further randomized controlled trials of MT plus eptifibatide should be prioritized. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03844594 (EPOCH), NCT03370939 (ANGEL-ACT).

A comparison between different endovascular treatment strategies for acute large vessel occlusion due to intracranial artery atherosclerosis: data from ANGEL-ACT Registry.

PURPOSE: The aim of our study is to compare the characteristics and clinical outcomes among the different endovascular treatment (EVT) strategies for large vessel occlusion underlying intracranial atherosclerosis (ICAS-LVO) in a recent nationwide registry. METHODS: Patients with isolated ICAS-LVO were enrolled in our analysis and were categorized into three groups: first-line mechanical thrombectomy (MT) with rescue angioplasty and/or stenting (MT + RS), direct angioplasty and/or stenting without thrombectomy (DA), and MT alone. Baseline and periprocedural characteristics, successful recanalization, and 90-day functional outcomes were compared. RESULTS: Of 396 patients with isolated ICAS-LVO in our study, successful recanalization was achieved in 94.5%, 100%, and 90.9% of patients in the MT + RS, DA, and MT groups, respectively. The 90-day functional independence in the three groups was 50.8%, 59.0%, and 45.1%. The main efficacy and safety outcomes showed no significant differences among the groups. First-pass recanalization (FPR) was more observed in the MT group (43.4%), the recanalization rate per attempt in the MT group gradually decreased until the fourth attempt, and further maneuvers showed recanalization rates of ≈0% per attempt. MT + RS (adjusted odds ratio [aOR] 0.10, p < 0.0001) and DA (aOR 0.18, p = 0.0013) were associated with lower FPR rate than MT alone in the multivariable logistic regression. CONCLUSIONS: The technical feasibility and favorable outcomes of several EVT strategies for ICAS-LVO were established in our study. First-line MT with a bailout angioplasty is a reasonable option for ICAS-LVO, and DA is an effective option for the cases when ICAS-LVO is strongly suspected before EVT procedure.

Genetic Algorithm and Greedy Strategy-Based Multi-Mission-Point Route Planning for Heavy-Duty Semi-Rigid Airship.

The large volume and windward area of the heavy-duty semi-rigid airship (HSA) result in a large turning radius when the HSA passes through every mission point. In this study, a multi-mission-point route planning method for HSA based on the genetic algorithm and greedy strategy is proposed to direct the HSA maneuver through every mission point along the optimal route. Firstly, according to the minimum flight speed and the maximum turning slope angle of the HSA during turning, the minimum turning radius of the HSA near each mission point is determined. Secondly, the genetic algorithm is used to determine the optimal flight sequence of the HSA from the take-off point through all the mission points to the landing point. Thirdly, based on the optimal flight sequence, the shortest route between every two adjacent mission points is obtained by using the route planning method based on the greedy strategy. By determining the optimal flight sequence and the shortest route, the optimal route for the HSA to pass through all mission points can be obtained. The experimental results show that the method proposed in this study can generate the optimal route with various conditions of the mission points using simulation studies. This method reduces the total voyage distance of the optimal route by 18.60% on average and improves the flight efficiency of the HSA.

Ultra-Wideband Microwave Imaging System for Root Phenotyping.

The roots are a vital organ for plant growth and health. The opaque surrounding environment of the roots and the complicated growth process means that in situ and non-destructive root phenotyping face great challenges, which thus spur great research interests. The existing methods for root phenotyping are either unable to provide high-precision and high accuracy in situ detection, or they change the surrounding root environment and are destructive to root growth and health. Thus,we propose and develop an ultra-wideband microwave scanning method that uses time reversal to achieve in situ root phenotyping nondestructively. To verify the method's feasibility, we studied an electromagnetic numerical model that simulates the transmission signal of two ultra-wideband microwave antennas. The simulated signal of roots with different shapes shows the proposed system's capability to measure the root size in the soil. Experimental validations were conducted considering three sets of measurements with different sizes, numbers and locations, and the experimental results indicate that the developed imaging system was able to differentiate root sizes and numbers with high contrast. The reconstruction from both simulations and experimental measurements provided accurate size estimation of the carrots in the soil, which indicates the system's potential for root imaging.

Novel Diffusion-Weighted Imaging Score Showed Good Prognostic Value for Acute Basilar Artery Occlusion Following Endovascular Treatment: The Pons-Midbrain and Thalamus Score.

BACKGROUND AND PURPOSE: Prognostic factors for outcome of endovascular treatment remains to be investigated in patients with acute basilar artery occlusion. We aimed to assess the prognostic value of a novel pretreatment diffusion-weighted imaging score: The Pons-Midbrain and Thalamus (PMT) score. METHODS: Eligible patients who underwent endovascular treatment due to acute basilar artery occlusion were reviewed. The PMT score was a diffusion-weighted imaging-based semiquantitative scale in which the infarctions of pons, midbrain, and thalamus were fully considered. The PMT score was assessed as well as the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score and Brain Stem Score. Good outcomes were defined as a modified Rankin Scale score of ≤3 at 90-day and successful reperfusion as Thrombolysis in Cerebral Infarction grades 2b/3. The associations between baseline clinical parameters and good outcomes were evaluated with logistic regression. RESULTS: A total of 107 patients with pretreatment magnetic resonance imaging were included in this cohort. The baseline PMT score (median [interquartile range], 3 [1-5] versus 7 [5-9]; P<0.001) and Brain Stem Score (median [interquartile range], 2 [1-4] versus 3 [2-5]; P=0.001) were significantly lower in good outcome group; the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score was higher in good outcome group without statistical significance. As a result of receiver operating characteristic curve analyses, the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score showed poor prognostic accuracy for good outcome (area under the curve, 0.60 [95% CI, 0.49-0.71]; P=0.081); The baseline PMT score showed significantly better prognostic accuracy for 90-day good outcome than the Brain Stem Score and National Institutes of Health Stroke Scale (area under the curve, 0.80 versus 0.68 versus 0.78, P=0.003). In addition, favorable PMT score <7 (odds ratio, 22.0 [95% CI, 6.0-80.8], P<0.001), Brain Stem Score <3 (odds ratio, 4.65 [95% CI, 2.05-10.55], P<0.001) and baseline National Institutes of Health Stroke Scale <23 (odds ratio, 8.0 [95% CI, 2.5-25.6], P<0.001) were associated with improved good outcome. CONCLUSIONS: In patients with acute basilar artery occlusion following endovascular treatment, the pretreatment diffusion-weighted imaging based PMT score showed good prognostic value for clinical outcome.

Thrombectomy Versus Combined Thrombolysis and Thrombectomy in Patients With Acute Stroke: A Matched-Control Study.

A recent randomized controlled trial DIRECT-MT (Direct Intra-Arterial Thrombectomy to Revascularize AIS Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals) compared the safety and efficacy of mechanical thrombectomy (MT) versus combined intravenous thrombolysis (IVT) and MT for acute large vessel occlusion. The current study utilized a prospective, nationwide registry to validate the results of the DIRECT-MT trial in a real-world practice setting. Subjects were selected from a prospective cohort of acute large vessel occlusion patients undergoing endovascular treatment at 111 hospitals from 26 provinces in China (ANGEL-ACT registry [Endovascular Treatment Key Technique and Emergency Work Flow Improvement of Acute Ischemic Stroke]) between November 2017 and March 2019. All patients eligible for IVT and receiving MT were reviewed and then grouped according to whether prior IVT or not (MT and combined IVT+MT). After a 1:1 propensity score matching, the outcome measures including the 90-day modified Rankin Scale, successful recanalization, door-to-puncture time, symptomatic intracranial hemorrhage, and intraprocedural embolization were compared. A total of 1026 patients, 600 in the MT group and 426 in the combined group, were included. Among 788 patients identified after matching, there were no significant differences in the 90-day modified Rankin Scale (median, 3 versus 3 points; P=0.82) and successful recanalization (86.6% versus 89.3%; P=0.23) between the two groups; however, patients of the MT group had a shorter door-to-puncture time (median, 112 versus 136 minutes; ß=−45.02 [95% CI, −68.31 to −21.74]), lower rates of symptomatic intracranial hemorrhage (5.5% versus 10.1%; odds ratio, 0.52 [95% CI, 0.30­0.91]), and embolization (4.6% versus 8.1%; odds ratio, 0.54 [95% CI, 0.30­0.98]) than those of the combined group. This matched-control study largely confirmed the findings of the DIRECT-MT trial in a real-world practice setting, suggesting that MT may carry similar effectiveness to combined IVT+MT for acute large vessel occlusion patients, despite MT alone seems to be associated with a shorter in-hospital delay until procedure, lower risks of symptomatic intracranial hemorrhage, and embolization. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03370939

Factors influencing early neurological improvement after mechanical thrombectomy among patients with acute basilar artery occlusion: a single center prospective observational cohort study.

The predictive value of and the influencing factors associated with early neurological improvement (ENI) among patients with acute basilar artery occlusion (BAO) have not been well studied. The present study aimed to evaluate whether ENI predicted a better functional outcome and to identify the influencing factors of ENI. We performed a prospective observational analysis among 187 patients with acute BAO who underwent endovascular treatment (EVT) in Beijing Tiantan Hospital from January 2012 to July 2018. ENI was defined as having a drop on the National Institutes of Health Stroke Scale (NIHSS) by 8 or more scores or having a NIHSS of 0-1 within 24 h after EVT. A multivariate logistic regression model with backward selection was used to identify the influencing factors associated with ENI. ENI had a sensitivity of 0.69 and a specificity of 0.68 to predict a favorable outcome at 90 days after EVT. In addition, patients with ENIs had lower modified Rankin Scale score (mRS) (median: 2.0 vs. 5.0, p < 0.001) and were more likely to survive (95.2% vs. 72.0%, p < 0.001) and achieve functional independence (74.2% vs. 36.8%, p < 0.001). NIHSS before EVT, complete recanalization, white blood cell counts and general anesthetics were significant factors associated with ENI. A one-unit higher NIHSS and complete recanalization were associated with 1.04 (95% CI 1.01-1.08) and 2.71 (95% CI 1.14-6.45) times higher odds of achieving ENI, respectively. In conclusion, in patients with acute BAO, ENI within 24 hours after EVT can predict favorable outcomes at 90 day. Patients with higher NIHSS, lower white blood cell counts before surgery, without general anesthetics and patients with complete recanalization were more likely to achieve ENIs.

Negative Index Metamaterial Lens for Subwavelength Microwave Detection.

Metamaterials are engineered periodic structures designed to have unique properties not encountered in naturally occurring materials. One such unusual property of metamaterials is the ability to exhibit negative refractive index over a prescribed range of frequencies. A lens made of negative refractive index metamaterials can achieve resolution beyond the diffraction limit. This paper presents the design of a metamaterial lens and its use in far-field microwave imaging for subwavelength defect detection in nondestructive evaluation (NDE). Theoretical formulation and numerical studies of the metamaterial lens design are presented followed by experimental demonstration and characterization of metamaterial behavior. Finally, a microwave homodyne receiver-based system is used in conjunction with the metamaterial lens to develop a far-field microwave NDE sensor system. A subwavelength focal spot of size 0.82λ was obtained. The system is shown to be sensitive to a defect of size 0.17λ × 0.06λ in a Teflon sample. Consecutive positions of the defect with a separation of 0.23λ was resolvable using the proposed system.

Capacitive imaging for adhesive bonds and quality evaluation.

Defective adhesive bonds pose significant threats towards structural integrity due to reduced joint strength. The nature of the adhesion of two solids remains poorly understood since the adhesion phenomenon is relevant to so many scientific and technological areas. A concept that has been gaining our attention from the perspective of non-destructive testing is the properties discontinuity of the adhesion. Discontinued properties depend significantly on the quality of the interface that is formed between adhesive and substrate. In this research, discontinued electrical properties at the interface are considered. The simplified model is free from multidisciplinary knowledge of chemistry, fracture mechanics, mechanics of materials, rheology and other subjects. From a practical standpoint, this emphasizes the need to establish a good relationship between electrical properties of adhesive bonds and corresponding measurements. Capacitive imaging (CI) is a technique where the dielectric property of an object is determined from external capacitance measurements. Thus, it is potentially promising since adhesive and substrate differ in terms of dielectric property. At the interface between adhesive and substrate, discontinuity of the dielectric properties causes abrupt changes in electric field spatial distribution and thus alters capacitance measurement by simulating defects in adhesive joints regarding permittivity uncertainties. Further understanding of the cause of degraded adhesion quality can be obtained. This article is part of the theme issue 'Advanced electromagnetic non-destructive evaluation and smart monitoring'.

Rotating Focused Field Eddy-Current Sensing for Arbitrary Orientation Defects Detection in Carbon Steel.

This paper presents a rotating focused field eddy-current (EC) sensing technique, which leverages the advantages of magnetic field focusing and rotating magnetic field, for arbitrary orientation defects detection. The sensor consists of four identical excitation coils orthogonally arranged in an upside-down pyramid configuration and a giant magneto-resistive (GMR) detection element. The four coils are connected to form two figure-8-shaped focusing sub-probes, which are fed by two identical harmonic currents with 90 degrees phase difference. A finite element model-based study of arbitrary orientation defects detection was performed to understand the probe operational characteristics and optimize its design parameters. Probe prototyping and experimental validation were also carried out on a carbon steel plate specimen with four prefabricated surface-breaking defects. In-situ spot inspection with the probe rotating above the defect and a manual line-scan inspection were both conducted. Results showed that the probe has the capability of detecting defects with any orientations while maintaining the same sensitivity and the defect depth can be quantitatively evaluated by using the signal amplitude. Compared with the existing rotating field probes, the presented probe does not require additional excitation adjustment or data fusion. Meanwhile, due to its focusing effect, it can generate a strong rotating magnetic field at the defect location with a weak background noise, thus yielding superior signal-to-noise ratio.

Continuous-Time Laser Frames Associating and Mapping via Multilayer Optimization.

To achieve the ability of associating continuous-time laser frames is of vital importance but challenging for hand-held or backpack simultaneous localization and mapping (SLAM). In this study, the complex associating and mapping problem is investigated and modeled as a multilayer optimization problem to realize low drift localization and point cloud map reconstruction without the assistance of the GNSS/INS navigation systems. 3D point clouds are aligned among consecutive frames, submaps, and closed-loop frames using the normal distributions transform (NDT) algorithm and the iterative closest point (ICP) algorithm. The ground points are extracted automatically, while the non-ground points are automatically segmented to different point clusters with some noise point clusters omitted before 3D point clouds are aligned. Through the three levels of interframe association, submap matching and closed-loop optimization, the continuous-time laser frames can be accurately associated to guarantee the consistency of 3D point cloud map. Finally, the proposed method was evaluated in different scenarios, the experimental results showed that the proposed method could not only achieve accurate mapping even in the complex scenes, but also successfully handle sparse laser frames well, which is critical for the scanners such as the new Velodyne VLP-16 scanner's performance.

Silencing of Long Noncoding RNA Nespas Aggravates Microglial Cell Death and Neuroinflammation in Ischemic Stroke.

Background and Purpose- Ischemic stroke is one of the leading causes of morbidity and mortality worldwide and a major cause of long-term disability. Recently, long noncoding RNAs have been revealed, which are tightly associated with several human diseases. However, the functions of long noncoding RNAs in ischemic stroke still remain largely unknown. In the current study, for the first time, we investigated the role of long noncoding RNA Nespas in ischemic stroke. Methods- We used in vivo models of middle cerebral artery occlusion and in vitro models of oxygen-glucose deprivation to illustrate the effect of long noncoding RNA Nespas on ischemic stroke. Results- We found expression of Nespas was significantly increased in ischemic cerebral tissues and oxygen-glucose deprivation-treated BV2 cells in a time-dependent manner. Silencing of Nespas aggravated middle cerebral artery occlusion operation-induced IR injury and cell death. In addition, proinflammatory cytokine production and NF-κB (nuclear factor-κB) signaling activation were inhibited by Nespas overexpression. TAK1 (transforming growth factor-ß-activated kinase 1) was found to directly interact with Nespas, and TAK1 activation was significantly suppressed by Nespas. At last, we found Nespas-inhibited TRIM8 (tripartite motif 8)-induced K63-linked polyubiquitination of TAK1. Conclusions- We showed that Nespas played anti-inflammatory and antiapoptotic roles in cultured microglial cells after oxygen-glucose deprivation stimulation and in mice after ischemic stroke by inhibiting TRIM8-related K63-linked polyubiquitination of TAK1.

Overexpression of miR-224-3p alleviates apoptosis from cerebral ischemia reperfusion injury by targeting FIP200.

AIMS: In previous studies, numerous differential microRNAs (miRNAs) in cerebral ischemic/reperfusion (I/R) injury were identified using the miRNA microarray analysis. However, the relationship between miRNA and cerebral I/R injury remains largely unknown. In this study, we investigated the function and explored the possible mechanism of miR-224-3p in cerebral I/R injury. METHODS: Oxygen glucose deprivation model in N2a cells were used to perform the cerebral I/R injury in vitro. Trypan blue staining, reactive oxygen species (ROS) production, and caspase-3 were measured to evaluate the function of miR-224-3p. RESULTS: Overexpression of miR-224-3p alleviated the apoptosis induced by oxygen glucose deprivation (OGD) and cleaved caspase-3 was significantly reduced. We further provided the possible mechanism that miR-224-3p may protect cells from cerebral I/R injury by targeting FAK family-interacting protein (FIP200). Further rescue experiment proved that overexpression of FIP200 partially blocked the effect of miR-224-3p. CONCLUSIONS: We evaluated the function and mechanism of miR-224-3p in ischemic brain injury. miR-224-3p may serve as a potential target for new therapeutic intervention.

High-Sensitivity Real-Time Tracking System for High-Speed Pipeline Inspection Gauge.

Real-time tracking of pipeline inspection gauges (PIGs) is an important aspect of ensuring the safety of oil and gas pipeline inline inspections (ILIs). Transmitting and receiving extremely low frequency (ELF) magnetic signals is one of the preferred methods of tracking. Due to the increase in physical parameters of the pipeline including transportation speed, wall thickness and burial depth, the ELF magnetic signals received are short transient (1-second duration) and very weak (10 pT), making the existing above-ground-marker (AGM) systems difficult to operate correctly. Based on the short transient very weak characteristics of ELF signals studied with a 2-D finite-element method (FEM) simulation, a data fusion model was derived to fuse the envelope decay rates of ELF signals by a least square (LS) criterion. Then, a fast-decision-tree (FDT) method is proposed to estimate the fused envelope decay rate to output the maximized orthogonal signal power for the signal detection through a determined topology and a fast calculation process, which was demonstrated to have excellent real-time detection performance. We show that simulation and experimental results validated the effectiveness of the proposed FDT method, and describe the high-sensitivity detection and real-time implementation of a high-speed PIG tracking system, including a transmitter, a receiver, and a pair of orthogonal search coil sensors.