Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of defects.However,the extent of the lift-off effect on differential probes,including different coil structures,varies.In this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off effects.The eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element analysis.The analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off distance.The peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental methods.In addition,the effects of different frequencies on the lift-off were studied experimentally.The results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 mm.In addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via normalization.This indicates that the influence becomes more evident with an increase in excitation frequency.This research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

Activatable fluorescent probes for imaging and diagnosis of rheumatoid arthritis

Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affecting locomotion ability and life quality.Consequently,good prognosis heavily relies on the early diagnosis and effective therapeutic monitoring of RA.Activatable fluorescent probes play vital roles in the detection and imaging of biomarkers for disease diagnosis and in vivo imaging.Herein,we review the fluorescent probes developed for the detection and imaging of RA biomarkers,namely reactive oxygen/nitrogen species(hypochlorous acid,peroxynitrite,hydroxyl radical,nitroxyl),pH,and cysteine,and address the related challenges and prospects to inspire the design of novel fluorescent probes and the improvement of their performance in RA studies.

Progress in Mechanical Modeling of Implantable Flexible Neural Probes

Implanted neural probes can detect weak discharges of neurons in the brain by piercing soft brain tissue,thus as important tools for brain science research,as well as diagnosis and treatment of brain diseases.However,the rigid neural probes,such as Utah arrays,Michigan probes,and metal microfilament electrodes,are mechanically unmatched with brain tissue and are prone to rejection and glial scarring after implantation,which leads to a significant degradation in the signal quality with the implantation time.In recent years,flexible neural electrodes are rapidly developed with less damage to biological tissues,excellent biocompatibility,and mechanical compliance to alleviate scarring.Among them,the mechanical modeling is important for the optimization of the structure and the implantation process.In this review,the theoretical calculation of the flexible neural probes is firstly summarized with the processes of buckling,insertion,and relative interaction with soft brain tissue for flexible probes from outside to inside.Then,the corresponding mechanical simulation methods are organized considering multiple impact factors to realize minimally invasive implantation.Finally,the technical difficulties and future trends of mechanical modeling are discussed for the next-generation flexible neural probes,which is critical to realize low-invasiveness and long-term coexistence in vivo.

英汉笔译课程PROBE教学模式探究

作为本科翻译专业的一门核心课程,英汉笔译课程在培养学生英汉双语运用能力、翻译能力和跨文化能力,尤其是学生英译汉翻译实践能力作用明显。文章对“PROBE教学模式”进行概念诠释,从教学目标、课程设计、教学过程和学习评价四个方面探讨了“PROBE教学模式”在英汉笔译课程中的应用,最后提出几点建议,以期提高英汉笔译课程的教学效果。

Application and development of fluorescence probes in MINFLUX nanoscopy(invited paper)

The MINimal emission FLUXes(MINFLUX)technique in optical microscopy,widely recognized as the next innovative fluorescence microscopy method,claims a spatial resolution of 1-3 nm in both dead and living cells.To make use of the full resolution of the MINFLUX microscope,it is important to select appropriate fluorescence probes and labeling strategies,especially in living-cell imaging.This paper mainly focuses on recent applications and developments of fluorescence probes and the relevant labeling strategy for MINFLUX microscopy.Moreover,we discuss the deficiencies that need to be addressed in the future and a plan for the possible progression of MINFLUX to help investigators who have been involved in or are just starting in the field of super-resolution imaging microscopy with theoretical support.

Presheath formation and area design limit satellite-based Langmuir probes

In this article,the effect of the finite conductive surface area of a satellite on the use of satellite-based Langmuir probes is reviewed in light of the basic theory of asymmetric double Langmuir probes(ADLPs).Recent theoretical and experimental studies have discussed electron sheath/presheath formation and the electron Bohm criterion along with their implications for satellite-based Langmuir probes.The effects predicted by the latest theory of the electron Bohm criterion were not experimentally observed and the experimental results remain supportive of a critical area ratio(A_(L)/A_(S))_(crit)=(m_(i)/(2.3m_(e)))^(1/2)between the probe area A_(S)and the satellite area A_L as conventionally believed.A satellite-based Langmuir probe must satisfy this criterion to physically act as a single Langmuir probe.However,experimental investigations also found that high-energy electrons adversely affect(A_(L)/A_(S))_(crit)and a Langmuir probe's signal quality by giving additional electron current to A_(L).Based on these results,a number of limitations of the maximum probe area are derived when designing satellite-based Langmuir probes,with consideration of both the aim of the satellite and the plasma where the satellite-based probe works.These proposed measures are expected to only partially alleviate the effect of the inadequate satellite surface area on the application of satellite-based Langmuir probes.Using a larger satellite to carry a Langmuir probe remains the most viable means to obtain precise space plasma parameters.

Au@Ag Core-shell Nanorods Self-assembled on Polyelectrolyte Multilayers for Ultra-High Sensitivity SERS Fiber Probes

We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectrolyte (PE) multilayers,for which Au@Ag-NRs were controlled by adjusting the silver layer thickness.The effect of silver layer thickness of Au@Ag-NRs on the SERS performance of the fiber probe was investigated.The SERS fiber probe shows the best performance when the silver layer thickness is controlled at 8.57 nm.Under the condition of optimizing silver layer thickness,the fiber probe exhibits ultra-high sensitivity (i e,10^(-10) M crystalline violet,CV),good reproducibility (i e,RSD of 3.5%) and stability.Besides,electromagnetic field distribution of the SERS fiber probe was also investigated.The strongest enhancement is found within the core of fiber,whereas a weakened electromagnetic field exists in the fiber cladding layer.The SERS fiber probe can be a good candidate in ultra-trace detection for biomedical and environmental areas.

An exo Probe-based Reverse Transcription and Recombinase Polymerase Amplification for Rapid Detection of Feline Calicivirus in Cats

Feline calicivirus(FCV)was a highly prevalent RNA virus causing upper respiratory tract infections in cats through the mouth and nose around the world,result in the death of cats especially under 1 year old with upper respiratory tract disease(URTD)and virulent systemic disease(FCV-VSD)[1].Infected cats usually presented with mouth ulcers,salivation and gingivitis-stomatitis.Furthermore,both recovered cats and asymptomatic carriers can still carry and spread the FCV virus for extended periods of time,contributing to the potential for outbreak.This presented a significant threat to the health and lives of cats,and rare wildlife and took a heavy financial loss on the pet industry,making the prevention and control of the virus difficult.Hence,rapid identification of FCV in clinical samples was necessary to prevent the spread of FCV and avoid financial loss.

Analysis of deformation mechanisms in magnesium single crystals using a dedicated four-point bending tester

In this study,we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending tester.We prepared two single-crystal samples,oriented along the<1120>and<1010>directions,to assess the mechanisms of deformation when the initial basal slip was suppressed.In the<1120>sample,the primary{1012}twin(T1)was confirmed along the<1120>direction of the sample on the compression side with an increase in bending stress.In the<1010>sample,T1 and the secondary twin(T2)were confirmed to be along the<1120>direction,with an orientation of±60°with respect to the bending stress direction,and their direction matched with(0001)in T1 and T2.This result implies that crystallographically,the basal slip occurs readily.In addition,the<1010>sample showed the double twin in T1 on the compression side and the tertiary twin along the<1010>direction on the tension side.These results demonstrated that the maximum bending stress and displacement changed significantly under the bend loading because the deformation mechanisms were different for these single crystals.Therefore,the correlation between bending behavior and twin orientation was determined,which would be helpful for optimizing the bending properties of Mg-based materials.

Plasma potential measurements using an emissive probe made of oxide cathode

A novel emissive probe consisting of an oxide cathode coating is developed to achieve a low operating temperature and long service life.The properties of the novel emissive probe are investigated in detail,in comparison with a traditional tungsten emissive probe,including the operating temperature,the electron emission capability and the plasma potential measurement.Studies of the operating temperature and electron emission capability show that the tungsten emissive probe usually works at a temperature of 1800 K-2200 K while the oxide cathode emissive probe can function at about 1200 K-1400 K.In addition,plasma potential measurements using the oxide cathode emissive probe with different techniques have been accomplished in microwave electron cyclotron resonance plasmas with different discharge powers.It is found that a reliable plasma potential can be obtained using the improved inflection point method and the hot probe with zero emission limit method,while the floating point method is invalid for the oxide cathode emissive probe.

Distal-scanning common path probe for optical coherence tomography

In this paper,we present a distal-scanning common path probe for optical coherence tomography(OCT)equipped with a hollow ultrasonic motor and a simple and specially designed beam-splitter.This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process,experimentally compared to a conventional noncommon path probe.Furthermore,our design counteracts the attenuation of backscattering with depth and the fall-off of the signal,resulting in a more balanced signal range and greater imaging depth.Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of∼100dB and a lateral resolution of∼3μm.This low-cost probe offers simplified system configuration and excellent robustness,and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus.

Design of compact integrated diamond nitrogen-vacancy center quantum probe

An integrated quantum probe for magnetic field imaging is proposed,where the nitrogen–vacancy(NV)center fixed at the fiber tip is located on the periphery of flexible ring resonator.Using flexible polyimide(PI)as the substrate medium,we design a circular microstrip antenna,which can achieve a bandwidth of 140 MHz at Zeeman splitting frequency of 2.87 GHz,specifically suitable for NV center experiments.Subsequently,this antenna is seamlessly fixed at a three-dimensional-printed cylindrical support,allowing the optical fiber tip to extend out of a dedicated aperture.To mitigate errors originating from processing,precise tuning within a narrow range can be achieved by adjusting the conformal amplitude.Finally,we image the microwave magnetic field around the integrated probe with high resolution,and determine the suitable area for placing the fiber tip(SAP).

Temperature-controlled DCP Fluorescent Probe Based on Hydrogel-immobilized Quantum Dots Composite

A composite was created by incorporating the quantum dot-enhanced SiO_(2)nanoparticles within this hydrogel.Based on this composite,a temperature-controlled fluorescent probe for DCP was developed.A meticulous examination of this probe revealed its attributes and factors affecting its performance.By using temperature modulation,the probe was adept at detecting DCP concentrations ranging between 1.0×10^(-6)and 9.0×10^(-6)mol/L.Such a probe offers remarkable selectivity,repeatability,and robust stability,so that the detection of DCP can be carried out at different temperatures,and a fast,reliable,sensitive and low-cost intelligent detection method is realized.

Tb^(3+)-nucleic acid probe-based label-free and rapid detection of mercury pollution in food

Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluorescence of terbium ions(Tb^(3+))via binding with single-strand DNA.Mercury ion,Hg^(2+)induced thymine(T)-rich DNA strand to form a double-strand structure(T-Hg^(2+)-T),thus leading to fluorescence reduction.Based on the principle,Hg^(2+)can be quantified based on the fluorescence of Tb^(3+),the limit of detection was 0.0689μmol/L and the linear range was 0.1-6.0μmol/L.Due to the specificity of T-Hg^(2+)-T artificial base pair,the assay could distinguish Hg^(2+)from other metal ions.The recovery rate was ranged in 98.71%-101.34%for detecting mercury pollution in three food samples.The assay is low-cost,separation-free and mix-to-read,thus was a competitive tool for detection of mercury pollution to ensure food safety.

RNA SNP Detection Method With Improved Specificity Based on Dual-competitive-padlock-probe

Objective The detection of RNA single nucleotide polymorphism(SNP)is of great importance due to their association with protein expression related to various diseases and drug responses.At present,splintR ligase-assisted methods are important approaches for RNA direct detection,but its specificity will be limited when the fidelity of ligases is not ideal.The aim of this study was to create a method to improve the specificity of splintR ligase for RNA detection.Methods In this study,a dualcompetitive-padlock-probe(DCPLP)assay without the need for additional enzymes or reactions is proposed to improve specificity of splintR ligase ligation.To verify the method,we employed dual competitive padlock probe-mediated rolling circle amplification(DCPLP-RCA)to genotype the CYP2C9 gene.Results The specificity was well improved through the competition and strand displacement of dual padlock probe,with an 83.26%reduction in nonspecific signal.By detecting synthetic RNA samples,the method demonstrated a dynamic detection range of 10 pmol/L-1 nmol/L.Furthermore,clinical samples were applied to the method to evaluate its performance,and the genotyping results were consistent with those obtained using the qPCR method.Conclusion This study has successfully established a highly specific direct RNA SNP detection method,and provided a novel avenue for accurate identification of various types of RNAs.

A Study of Radiation-Induced Telomere Instability Using Multiplex Ligation-Dependent Probe Amplification (MLPA)

The integrity of the chromosomes for two WIL2-derived lymphoblastoid cell lines (TK6 and WTK1) in the presence and absence of ionizing radiation was analyzed by Multiplex Ligation-Dependent Probe Amplification (MLPA). The TK6 cell line has the native p53 tumor-suppressor gene, whereas WTK1 cells contain a p53 mutation. Each cell line was isolated pre- and post-irradiation (2 and 3 Gy) and analyzed by MLPA. The impact of irradiation on these two cell lines was investigated using probes that target specific regions on chromosomes associated with subtelomeric regions. Results indicate that WTK1 and TK6 are impacted differently after irradiation, and that each cell line presents its own unique MLPA profile. The most notable differences are the appearance of a number of probes in the post-irradiated MLPA profile that are not present in the controls, and two unique probe signals only seen in WTK1 cells. These results build on our previous studies that indicate how different human cell lines can be affected by radiation in significantly different ways depending on the presence or absence of wild type p53.

Metal-organic cage as fluorescent probe for LiPF_(6)in lithium batteries

Lithium hexafluorophosphate(LiPF_(6)),the most commonly used lithium battery electrolyte salt,is vulnerable to heat and humidity.Quantitative and qualitative determination the variation of LiPF_(6)have always relied on advanced equipment.Herein,we develop a fast,convenient,high-selective fluorescence detection method based on metal-organic cages(MOC),whose emission is enhanced by nearly 20 times in the presence of LiPF_(6)with good stability and photobleaching resistance.The fluorescent probe can also detect moisture in battery electrolyte.We propose and verify that the luminescence enhancement is due to the presence of hydrogen bond-induced enhanced emission effect in cages.Fluorescent excitation-emission matrix spectra and variable-temperature nuclear magnetic resonance spectroscopy are employed to clarify the role of hydrogen bonds in guest-loaded cages.Density functional theory(DFT)calculation is applied to simulate the structure of host-guest complexes and estimate the adsorption energy involved in the system.The precisely matched lock-and-key model paves a new way for designing and fabricating novel host structures,enabling specific recognition of other target compounds.

A High-Resolution Measurement Method for Inner and Outer 3D Surface Profiles of Laser Fusion Targets Using a Laser Differential Confocal–Atomic Force Probe Technique

The high-resolution and nondestructive co-reference measurement of the inner and outer threedimensional(3D)surface profiles of laser fusion targets is difficult to achieve.In this study,we propose a laser differential confocal(LDC)–atomic force probe(AFP)method to measure the inner and outer 3D surface profiles of laser fusion targets at a high resolution.This method utilizes the LDC method to detect the deflection of the AFP and exploits the high spatial resolution of the AFP to enhance the spatial resolution of the outer profile measurement.Nondestructive and co-reference measurements of the inner profile of a target were achieved using the tomographic characteristics of the LDC method.Furthermore,by combining multiple repositionings of the target using a horizontal slewing shaft,the inner and outer 3D surface profiles of the target were obtained,along with a power spectrum assessment of the entire surface.The experimental results revealed that the respective axial and lateral resolutions of the outer profile measurement were 0.5 and 1.3 nm,while the respective axial and lateral resolutions of the inner profile measurement were 2.0 nm and approximately 400.0 nm.The repeatabilities of the rootmean-square deviation measurements for the outer and inner profiles of the target were 2.6 and 2.4 nm,respectively.We believe our study provides a promising method for the high-resolution and nondestructive co-reference measurement of the inner and outer 3D profiles of laser fusion targets.

A highly sensitive fluorescent probe RN-NA reveals peroxynitrite as a novel biomarker for primary open angle glaucoma

AIM:To directly quantify peroxynitrite(ONOO-)using a highly sensitive fluorescence resonance energy transfer probe RN-NA,investigate the association between ONOOand primary open angle glaucoma(POAG),and clarify whether RN-NA could be used as a potential tool for POAG diagnosis.METHODS:Plasma and aqueous humor(AH)samples were collected from POAG patients(n=100,age:59.70±6.87y)and age-related cataract(ARC)patients(n=100,age:61.15±4.60y)admitted to our hospital.Next,RN-NA was used to detect ONOO-in plasma and AH samples,and the relationship between ONOO-level and POAG was analyzed using binary logistic regression.Besides,Pearson correlation analysis was applied to characterize the correlation of the levels of ONOO-with the patients’age,intraocular pressure(IOP),and mean deviation of visual field testing.The ONOO-scavenger MnTMPyP was employed to treat the 3-morpholinosyndnomine(SIN-1)-induced ocular hypertension in mice(n=7,6-8wk).Finally,the IOP and ONOO-in both eyes were measured 30min after the last drug treatment.RESULTS:ONOO-levels of AH and plasma were significantly higher in the POAG group than in the ARC group(P<0.01).Additionally,ONOO-levels were closely correlated with POAG in a binary logistic regression analysis[odds ratio(OR)=1.008,95%confidence interval(CI):1.002-1.013,P<0.01 for AH;OR=1.004,95%CI:1.002-1.006,P<0.001 for plasma].Pearson correlation analysis showed that ONOO-levels in AH or plasma were positively associated with visual field defects(R=0.51,P<0.01 for AH;R=0.45,P<0.001 for plasma),and ONOO-levels in plasma and AH were correlated in the POAG group(R=0.69,P<0.001).However,administering MnTMPyP to mouse eyes reversed the elevated IOP caused by SIN-1(P<0.05).CONCLUSION:ONOO-levels in AH and plasma,detected by RN-NA,are significantly related to POAG and positively correlated with visual field defects in POAG patients.Hence,ONOO-is a potential biomarker of POAG,especially advanced POAG.Besides,anti-nitration compounds may be novel ocular hypotensive agents based on the animal study.

Poloidal magnetic field reconstruction by laser-driven ion-beam trace probe in spherical tokamak

The poloidal magnetic field( B_(p)) plays a critical role in plasma equilibrium, confinement and transport of magnetic confinement devices. Multiple diagnostic methods are needed to complement each other to obtain a more accurate B_(p) profile. Recently, the laser-driven ion-beam trace probe(LITP) has been proposed as a promising tool for diagnosing B_(p) and radial electric field( E_(r)) profiles in tokamaks [Yang X Y et al 2014 Rev. Sci. Instrum. 85 11E429]. The spherical tokamak(ST) is a promising compact device with high plasma beta and naturally large elongation. However, when applying LITP to diagnosing B_(p) in STs, the larger B_(p) invalidates the linear reconstruction relationship for conventional tokamaks, necessitating the development of a nonlinear reconstruction principle tailored to STs. This novel approach employs an iterative reconstruction method based on Newton's method to solve the nonlinear equation. Subsequently,a simulation model to reconstruct the B_(p) profile of STs is developed and the experimental setup of LITP is designed for EXL-50, a middle-sized ST. Simulation results of the reconstruction show that the relative errors of B_(p) reconstruction are mostly below 5%. Moreover, even with 5 mm measurement error on beam traces or 1 cm flux surface shape error, the average relative error of reconstruction remains below 15%, initially demonstrating the robustness of LITP in diagnosing B_(p) profiles in STs.