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We aimed to determine the safety of direct oral anticoagulants (DOACs) for stroke prevention and treatment in patients with atrial fibrillation (AF). A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting severe bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated. Twenty-three RCTs met the inclusion criteria, and a total of 87,616 patients were enrolled. The bleeding safety of DOACs for stroke prevention and treatment in patients with AF was ranked from highest to lowest as follows: fatal bleeding: edoxaban (SUCRA,80.2), rivaroxaban (SUCRA,68.3), apixaban (SUCRA,48.5), dabigatran (SUCRA,40.0), VKAs (SUCRA,12.9); major bleeding: dabigatran (SUCRA,74.0), apixaban (SUCRA,71.5), edoxaban (SUCRA,66.5), rivaroxaban (SUCRA,22.7), VKAs (SUCRA,15.4); gastrointestinal bleeding: apixaban (SUCRA,55.9), VKAs (SUCRA,53.7), edoxaban (SUCRA,50.5), rivaroxaban (SUCRA,50.4), dabigatran (SUCRA,39.5); intracranial hemorrhage: dabigatran (SUCRA,84.6), edoxaban (SUCRA,74.1), apixaban (SUCRA,65.8), rivaroxaban (SUCRA,24.4), VKAs (SUCRA,1.1). Based on current evidence, for stroke prevention and treatment in patients with AF, the most safe DOAC is edoxaban in terms of fatal bleeding; dabigatran in terms of major bleeding and intracranial hemorrhage and apixaban in terms of gastrointestinal bleeding. However, given the nature of indirect comparisons, more high-quality evidence from head-to-head comparisons is still needed to confirm them.

A metal clad plate consists of a base layer and a clad layer of different materials. When testing clad plate using the eddy current (EC) method, the variation of EC density along the thickness dire...

Virtual reality technology has begun to be gradually applied to clinical stroke rehabilitation. The study aimed to evaluate the effect of traditional plus virtual reality rehabilitation on motor function recovery, balance, and activities of daily living in stroke patients.Studies published in English before October 2020 were retrieved from PubMed, Embase, Web of Science, and the Cochrane Library. This study used RevMan 5.3 software for meta-analysis.A total of 21 randomized controlled trials were included, which enrolled 619 patients. Traditional plus virtual reality rehabilitation is better than traditional rehabilitation in upper limb motor function recovery measured by Fugl-Meyer Assessment-Upper Extremity (mean difference = 3.49, 95% confidence interval = 1.24 to 5.73, P = 0.002) and manual dexterity assessed by Box and Block Test (mean difference = 6.59, 95% confidence interval = 3.45 to 9.74, P0.0001). However, there is no significant difference from traditional rehabilitation in activities of daily living assessed by Functional Independence Measure (mean difference = 0.38, 95% confidence interval = -0.26 to 1.02, P = 0.25) and balance assessed by Berg Balance Scale (mean difference = 2.18, 95% confidence interval = -0.35 to 4.71, P = 0.09).Traditional plus virtual reality rehabilitation therapy is an effective method to improve the upper limb motor function and manual dexterity of patients with limb disorders after stroke, and immersive virtual reality rehabilitation treatment may become a new option for rehabilitation after stroke.

A radical reaction is a type of highly efficient organic reaction with a broad coverage in organic synthesis. However, its potential in the preparation of energetic materials is grossly underexplored. Now a novel nitrogen-centered radical reaction was discovered which features an N–N coupling capability, able to couple a pyrazole-based energetic compound to its N–N bridged dimer. The reaction exhibits high efficiency, while maintaining the traits of being mild, green, and facile without assistance from metal catalysis, photolysis, electrolysis or pyrolysis. The radical reaction mechanism was verified by a radical scavenger experiment and electron spin resonance spectroscopy.

Detection of fiber fracture in unidirectional carbon-fiber-reinforced polymer (CFRP) using the conventional eddy-current method is difficult due to the low electrical conductivity of the material. This article explores the possibility of detecting fiber fracture using the remote field eddy-current method. A remote field eddy-current probe consisting of an excitation coil and a reception coil is designed and optimized. The experimental results show that the signal of scanning the probe over fiber fracture has a dual-valley characteristic and the distance between the two minima is identical to the distance between the coil axes. This characteristic of signal is analyzed by studying distributions of eddy current (EC) using a finite-element analysis. A comparison of the testing results of the remote field EC probe and the conventional EC probes demonstrates the superiority of the remote field EC method in detecting fiber fracture in unidirectional carbon-fiber-reinforced polymer.

Human adenoviruses (HAdVs) are highly contagious and result in large number of acute respiratory disease (ARD) cases with severe morbidity and mortality. Human adenovirus type 3 (HAdV-3) is the most common type that causes ARD outbreaks in Asia, Europe, and the Americas. However, there is currently no vaccine approved for its general use. The hexon protein contains the main neutralizing epitopes, provoking strong and lasting immunogenicity. In this study, a novel recombinant and attenuated adenovirus vaccine candidate against HAdV-3 was constructed based on a commercially-available replication-defective HAdV-5 gene therapy and vaccine vector. The entire HAdV-3 hexon gene was integrated into the E1 region of the vector by homologous recombination using a bacterial system. The resultant recombinants expressing the HAdV-3 hexon protein were rescued in AD293 cells, identified and characterized by RT-PCR, Western blots, indirect immunofluorescence, and electron microscopy. This potential vaccine candidate had a similar replicative efficacy as the wild-type HAdV-3 strain. However, and importantly, the vaccine strain had been rendered replication-defective and was incapable of replication in A549 cells after more than twenty-generation passages in AD293 cells. This represents a significant safety feature. The mice immunized both intranasally and intramuscularly by this vaccine candidate raised significant neutralizing antibodies against HAdV-3. Therefore, this recombinant, attenuated, and safe adenovirus vaccine is a promising HAdV-3 vaccine candidate. The strategy of using a clinically approved and replication-defective HAdV-5 vector provides a novel approach to develop universal adenovirus vaccine candidates against all the other types of adenoviruses causing ARDs and perhaps other adenovirus-associated diseases.

Background Stroke patients have low medication adherence after discharge, which leads to a high recurrence rate and poor disease control. Various strategies have been explored to enhance medication adherence in this patient population. Aim To evaluate the effects of mobile health (mHealth) and telehealth technology on medication adherence in stroke patients. Method All English studies that met the inclusion criteria published before September 2021 were obtained from PubMed, EMBASE, Web of Science, and Cochrane Library. Two researchers independently screened articles, extracted data, and evaluated the quality of the included studies. All articles were about randomized controlled trials. Medication adherence was used as the outcome index of this review. Random or fixed-effect models were used in statistical methods. I2 statistics were used to evaluate heterogeneity. Results A total of ten studies met the inclusion criteria, covering 2151 stroke patients. Compared with the Usual Care group, the medication adherence scores of the mHealth technology group were better (standard mean deviation 0.67, 95% confidence interval, CI [0.49, 0.85], P < 0.001). The medication adherence ratio of the mHealth technology group was higher (odds ratio, OR, 2.81, 95% CI [1.35, 5.85], P = 0.006). Subgroup analysis showed that application and messaging interventions were more effective than the telephone call intervention (OR 4.05, 95% CI [2.10, 7.80], P < 0.001). The shorter the interval of the intervention, the better the medication adherence of patients (OR 4.24, 95% CI [2.30, 7.81], P < 0.001). Conclusion Compared with Usual Care, mHealth can effectively improve the medication adherence of stroke patients.

Background Breastfeeding is essential for maintaining the health of mothers and babies. Breastfeeding can reduce the infection rate and mortality in newborns, and can reduce the chances of overweight and obesity in children and adolescents. For mothers, a longer duration of breastfeeding can reduce the risk of breast cancer, ovarian cancer, and type 2 diabetes. Although breastfeeding has many benefits, the global breastfeeding rate is low. With the progress of time, the popularity of mobile devices has increased rapidly, and interventions based on mobile health (mHealth) may have the potential to facilitate the improvement of the breastfeeding status. Objective The main objective of this study was to analyze the existing evidence to determine whether mHealth-based interventions can improve the status of breastfeeding. Methods We systematically searched multiple electronic databases (PubMed, Web of Science, The Cochrane Library, Embase, CNKI, WanFang, and Vip ) to identify eligible studies published from 1966 to October 29, 2020. Included studies were randomized controlled trials (RCTs) studying the influence of mHealth on breastfeeding. The Cochrane Collaboration Risk of Bias tool was used to examine the risk of publication bias. RevMan 5.3 was used to analyze the data. Results A total of 15 RCTs with a total sample size of 4366 participates met the inclusion criteria. Compared with usual care, interventions based on mHealth significantly increased the postpartum exclusive breastfeeding rate (odds ratio [OR] 3.18, 95% CI 2.20-4.59; P Conclusions Interventions based on mHealth can significantly improve the rate of postpartum exclusive breastfeeding, breastfeeding efficacy, and participants’ attitudes toward breastfeeding, and reduce health problems in infants. Therefore, encouraging women to join the mHealth team is feasible, and breastfeeding-related information can be provided through simple measures, such as text messages, phone calls, and the internet, to improve the health of postpartum women and their babies.

In order to control the quality of carbon fiber reinforced polymer in the production process, a method of detecting fiber waviness in carbon fiber prepreg using eddy current (EC) probe is proposed. The EC probe includes orthogonal rectangular coils. The excitation coil is parallel to the designed fiber direction, so that the output voltage of the reception coil is only related to the bending of EC caused by fiber waviness. The phase of the output voltage is used for characterizing fiber direction. The results show that the probe is able to distinguish fiber direction as small as 0.5° and fiber waviness in prepreg can be detected. Moreover, algorithm of reconstructing fiber distribution is proposed and fiber waviness is visualized.

Background Low back pain is one of the most common health problems and a main cause of disability, which imposes a great burden on patients. Mobile health (mHealth) affects many aspects of people’s lives, and it has progressed rapidly, showing promise as an effective intervention for patients with low back pain. However, the efficacy of mHealth interventions for patients with low back pain remains unclear; thus, further exploration is necessary. Objective The purpose of this study was to evaluate the efficacy of mHealth interventions in patients with low back pain compared to usual care. Methods This was a systematic review and meta-analysis of randomized controlled trials designed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) statement standard. We searched for studies published in English before October 2020 in the PubMed, EMBASE, Web of Science, and Cochrane Library databases. Two researchers independently scanned the literature, extracted data, and assessed the methodological quality of the included studies. Bias risks were assessed using the Cochrane Collaboration tool. We used RevMan 5.4 software to perform the meta-analysis. Results A total of 9 studies with 792 participants met the inclusion criteria. The simultaneous use of mHealth and usual care showed a better reduction in pain intensity than usual care alone, as measured by the numeric rating scale (mean difference [MD] –0.85, 95% CI –1.29 to –0.40; P Conclusions The use of simultaneous mHealth and usual care interventions has better efficacy than usual care alone in reducing pain intensity and disability in patients with low back pain. Moreover, the results of subgroup analysis revealed that mHealth using telephone calls might play a positive role in improving pain intensity and disability in patients with low back pain.

Skin depth is an important parameter that quantifies depth of inspection of eddy current (EC) nondestructive testing. The formula which states that the skin depth is inversely proportional to the square root of the product of frequency, permeability, and conductivity has been widely used for calculating skin depth for many decades. It has been noticed that the true skin depth is less than that obtained by the formula when the EC is excited by the ac current in a pancake coil. In-depth and convincible explanation of this discrepancy has not been published. This paper studies this problem by finite-element analysis and concludes that the difference is due to two reasons. One is that the EC associated with pancake coil diffuses with increasing depth, whereas there is no diffusion effect of EC associated with uniform plane field which is the assumption of the conventional formula. The other reason is that the ECs induced by wire segments symmetric about the coil axis cancel each other and the cancellation becomes more severe with increasing depth due to the diffusion of EC. This paper also investigates the influence of each of coil parameters on skin depth. Then, a new formula for estimating skin depth is proposed.

Eddy current testing (ECT) is an important nondestructive testing technology for the inspection of flaws in conductive materials. However, this widely used technology is not suitable for inspecting lamination when a conventional pancake coil is used because the eddy current (EC) generated by the pancake coil is parallel to the lamination and will not be perturbed. A new method using a rectangular coil placed vertical to the work piece is proposed for lamination detection. The vertical sections of the rectangular coil induce ECs that are vertical to the lamination and can be perturbed by the lamination. A parametric study of a rectangular coil by finite element analysis was performed in order to examine the capability of generating vertical EC.

The paper studies the characteristics of eddy current (EC) distribution in carbon fiber reinforced polymer (CFRP) laminates so as to guide the research and operation of eddy current testing of CFRP. To this end, an electromagnetic field computation model of EC response to CFRP based on the finite element method is developed. Quantitative analysis of EC distribution in plies of unidirectional CFRP reveals that EC changes slowly along the fiber direction due to the strong electrical anisotropy of the material. Variation of EC in plies of multidirectional CFRP is fast in both directions. The attenuation of EC in the normal direction in unidirectional CFRP is faster than that in isotropic material due to faster diffusion of EC. In multidirectional CFRP, EC increases near the interfaces of plies having different fiber orientations. The simulation results are beneficial to optimizing sensor design and testing parameters, as well as damage detection and evaluation.

In this paper, a method of detecting fiber waviness in carbon fiber reinforced polymer (CFRP) using eddy current (EC) probe is proposed. The probe consists of a rectangular excitation coil and a rectangular reception coil that are perpendicular to each other. The excitation coil is along the designed fiber direction. Fiber waviness changes the direction of EC and generates a magnetic field component that is normal to the reception coil; thereby an output signal is obtained. The results of simulation and experiments show that the resolution of testing fiber direction using the proposed method is as small as 0.5° and fiber waviness can be detected according to the variation of scanning signal.

Pulsed eddy current (PEC) testing has attracted researchers' interest because the pulsed excitation comprises a broad band of frequencies and the response signal provides more information about defect than traditional eddy current testing. Various features have been extracted from PEC signal for defect characterization. In this paper, we extract frequency-domain features and propose defect characterization scheme for identifying defect's location, radius, and height.

Eddy-current testing (ECT) is widely used in inspection of multilayer aircraft skin structures for the detection of cracks under fasteners (CUF). Detection of deep hidden CUF poses a major challenge in traditional ECT techniques largely because the weak eddy-current signal due to a subsurface crack is dominated by the strong signal from the aluminum or steel fastener. Giant magnetoresistive (GMR) sensors are finding increasing applications in directly measuring weak magnetic fields associated with induced eddy currents. The measured flux image at a fastener site is in general symmetric and an asymmetry is introduced by the presence of a subsurface crack, which is used for defect detection. This paper presents novel methods that employ the resident phase information, for improving detection probability of GMR signal analysis. Using computational model, the effectiveness of the proposed methods for enhancing detection of CUF is investigated. Results demonstrating the potential of these techniques for detection of second layer CUF are presented.

A novel design of eddy current probe based on rotating magnetic fields is presented for the inspection of steam generator tubes in nuclear power plants. A major advantage of the rotating field probe is that it offers the same functiona lity as that of a rotating probe coil without the need for mechanical rotation, which in turn translates into higher operating sp eed. The probe design is also sensitive to cracks of all orientations in the tube wall.

Industrial components are often case hardened to improve their strength and wear characteristics. Traditionally, component samples are collected from the production line at specific intervals and destructively tested for case depth profile assessment. This process is time-consuming, laborious, and can potentially allow an improperly treated component to escape detection. This paper presents a novel nonlinear eddy current technique for assessing the case hardening profile based on the premise that the magnetic characteristic of the case hardened region is different from that of the host material. A custom electromagnetic excitation-sensor array is used to both apply sinusoidal excitations to the component and measure the nonlinear response at multiple excitation frequencies and spatial locations, taking advantage of the different penetration regions due to the skin depth phenomenon. Each response signal obtained from the component under test is compared with that from a reference component subjected to the same excitation. Two pattern recognition algorithms (an artificial neural network and the Iterative Dichotomiser 3 (ID3) algorithm) are then used to process selected characteristics of the difference signal to determine the case depth profile of the component. The nonlinear eddy current technique has been applied to evaluate the case hardening profile of automotive bearing assemblies. This problem is challenging due to the variations in geometry across assemblies as well as the limited accessibility to the case hardened surface. In the neural network test, the system achieved a 95.77% accuracy. For the ID3 algorithm, the system achieved a 95.65% accuracy. These results demonstrate that the nonlinear eddy current inspection technique is highly promising in characterizing the case profile of induction hardened parts.

Research in nondestructive evaluation is constantly increasing the sensitivity of detection of small cracks embedded deep in layered aircraft structures. Pulsed eddy-current (PEC) techniques using coil probes have shown considerable promise in detection and characterization of buried cracks in multilayered structures. In this paper, we describe the design and development of a nondestructive inspection system that uses pulse excitation of a planar multiline coil to generate a transient field that is detected via a giant magnetoresistive (GMR) field sensor. An analysis algorithm using features in time and frequency domain processes the experimentally measured signals for automatic detection of small cracks under fasteners in multilayered structures at a depth of up to 10 mm.

The finite-element method is widely used in modeling eddy-current phenomena. However, its application in eddy-current nondestructive testing involving probe motion requires remeshing for each coil position. Remeshing is not only cumbersome but also a major source of computational noise. We have used the reduced magnetic vector potential formulation to model an air-core probe scan without remeshing the coil in different positions. In this paper, we present a method to model the scanning of ferrite-core probe. With this method, finite-element meshes for the test sample and the ferrite core are generated separately. The coil is not meshed. The magnetic field and magnetic vector potential due to the coil are evaluated analytically. An iterative but fast procedure is used to update the total field. The method is simple, flexible, accurate, and efficient.

Three-dimensional finite element (FE) modeling of remote field eddy current (RFEC) technique has been performed to detect localized defects in ferromagnetic steam generator tubes. The excitation frequency, intercoil spacing, and the design of localized receiver coil have been optimized using this model. Amplitude and phase of RFEC signals of radial and axial receiver coils have been predicted for a through hole and two flat bottom holes (FBH). The detection sensitivity of the receiver coils has been compared, and the model has been validated for a few cases.

The use of reduced magnetic vector potential (RMVP) in the three-dimensional finite element analysis of eddy current nondestructive testing (ECT) has demonstrated great flexibility, accuracy, and efficiency in case of coil excitation. This paper investigates the application of the RMVP in another class of eddy-current testing applications where the test sample of finite size is immersed in a uniform excitation field. The paper also shows that RMVP cannot be used in eddy-current testing problems having infinite current foil and infinite conducting plates.

Magneto-optic imaging (MOI) is an emerging hybrid imaging technique that innovatively generates two-dimensional images by combining electromagnetic and optical energies. It has been widely used in detecting surface and subsurface cracks and corrosion in aircraft skins for nondestructive testing purpose. The merits of the MOI that make it attractive include rapid and large-area inspection, insensitivity to liftoff variation, and easy interpretation in contrast to the complex impedance data of conventional eddy current inspections. The early instrument provides binary images of the anomalies based on eddy current induction techniques and an MO sensor using the Faraday’s rotation effect. This chapter will give a comprehensive review on this relatively new sensing technology and discuss the recent advances on MOI including the development of novel optical sources and magnetic film materials for various applications, the integration of MOI sensors with automated systems, and the state-of-the-art post-processing algorithms.

Magneto-optic/eddy current imaging (MOI) has become increasingly popular for inspecting aging aluminum airframes for cracks and corrosion due to its accuracy, reliability, and ease of use. As inspection requirements change, modifications to the MOI system must be made to improve sensitivity and resolution to reliably detect smaller and/or deeper defects in the aircraft structure. Incorporating such improvements by "cut and try" methods is time-consuming and expensive. Therefore, a numerical simulation model that produces quantitative values of the magnetic fields associated with induced eddy currents interacting with structural defects is an essential complement to the instrument development process. Such a model provides a convenient tool for parametrically evaluating the effectiveness of the MOI for detecting various structural defects. This paper presents a three-dimensional finite-element model of Maxwell's equations, utilizing the A-V formulation for numerical simulation of the MOI operation. The model is used to predict quantitative values of field distributions that produce the binary magneto-optic images of subsurface fatigue cracks at rivet sites in an aluminum airframe structure. A parametric study is performed to determine the effects of MOI operational parameters on the binary images. A skewness parameter based on the binary images is established to provide a measure of defect size. This parameter will prove useful for automatic detection and classification of defects. The model-generated images show good agreement with experimentally derived MOI images

Meshless methods have attracted great attention due to their advantage in geometric representation. In this paper, a meshless element-free Galerkin method is applied for the first time to solve pulsed eddy-current problems. Detailed mathematical derivations and the numerical implementation are discussed. The model is validated against analytic solutions for two canonical cases.

Compared with the conventional finite element method that relies on an underlying mesh and element-node connectivity to describe the geometry, meshless method shows its advantage in mesh simplification, tight crack representation and re-meshing process. An effective numerical implementation of the meshless method uses the Galerkin technique and is referred to as the element-free Galerkin (EFG) method. In this paper, the EFG method is applied to a field of electromagnetic computation, namely, simulation of pulsed eddy current testing. The model is validated against analytical solutions.

Onsite real-time nondestructive evaluation of aircraft using eddy current techniques has gained significance in the past few years. In this paper, emphasis is placed on developing a flexible and a fast real-time inspection system using giant magnetoresistive (GMR) field sensors. Experimental signals are compared with finite-element model (FEM) model simulations and signals acquired using traditional data acquisition methods. Several advantages of the improved design are discussed

The detection of embedded cracks under fastener heads (CUF) in multilayer structures is a major challenge facing the aviation industry. Eddy current (EC) based techniques, such as Magneto-Optic Imager, Sliding probe and Self-nulling EC probes, and low frequency EC methods have been investigated. The prior work of authors presented an EC system using a uniform field excitation combined with giant magnetoresistive (GMR) sensors for imaging the normal component of magnetic flux density, has improved the effectiveness in detecting 2nd and 3rd layer CUFs with aluminum fasteners. However, detection of CUFs with ferromagnetic fasteners remains a major challenge. This paper presents the experimental study of automatic crack detection under steel fastener sites using low frequency EC with 3D GMR sensors that measure all 3 components of the induced magnetic flux density. A finite element model based study is used to optimize the system design and the experimental validation is presented.

The magneto-optic imager (MOI) is widely used in detecting surface and subsurface cracks and corrosion in aircraft skins. The instrument provides analog images of the anomalies based on eddy current induction techniques and a magneto-optic (MO) sensor using the Faraday rotation effect. The merits of the MOI that make it attractive include rapid and large-area inspection, insensitivity to liftoff variations, and easy interpretation in contrast to the complex impedance data of conventional eddy current inspections. The current MOI system lacks the capability of providing a quantitative measure of the defects. In addition, the presence of noise due to the underlying domain structures in the MO sensor can lead to inconsistent accept or reject decisions by the inspector. This paper presents an image processing and automated classification algorithm for MO image analysis and also provides a quantitative basis for characterizing these images

This paper presents results obtained by simulating the second magnetic flux leakage benchmark problem proposed by the World Federation of NDE Centers. The geometry consists of notches machined on the internal and external surfaces of a rotating steel pipe that is placed between two yokes that are part of a magnetic circuit energized by an electromagnet. The model calculates the radial component of the leaked field at specific positions. The nonlinear material property of the ferromagnetic pipe is taken into account in simulating the problem. The velocity effect caused by the rotation of the pipe is, however, ignored for reasons of simplicity.

Finite element methods (FEM) are widely used for modeling a variety of problems in Nondestructive Evaluation (NDE). For example, in the modeling of multilayer aircraft geometry with third layer cracks under fasteners, the reliance of FEM on a mesh leads to several problems, particularly when tight cracks have to be introduced into the sample. Furthermore remeshing is often required in handling probe motion can be time consuming. This paper presents a meshless element-free Galerkin method (EFG), where the approximation is entirely constructed in terms of a set of nodes. The model is validated and applied to two dimensional magneto-static and eddy current NDT problems.