Depth Resolution Research Articles

A tool wear monitoring method driven by workpiece surface quality inversion and EfficientNet

Abstract Tool wear status monitoring plays an important role in the safety of machine and the efficiency of production. Due to the limitation of sensor installation and complex operation conditions, traditional machine vision methods are difficult to directly act on the tool itself to obtain corresponding wear status information. Meanwhile, the surface quality of the machined workpiece can provide indirect insights into the wear status of the tool to a significant degree. Therefore, an indirect tool wear status monitoring method is proposed in this paper by workpiece surface quality inversion and EfficientNet. Firstly, the surface texture data of workpiece are obtained in the form of image by an industrial camera, and the representative features that indirectly reflect tool wear status are further highlighted by using the weighted average image grayscale and the Laplacian operator. Secondly, to monitor tool wear effectively, we've optimized three key settings, width, model depth, and input image resolution, of the EfficientNet backbone network. This optimization boosts its ability to understand and generalize, ensuring it can handle various surface textures and extract crucial information accurately. This, in turn, enhances the accuracy of our tool wear monitoring system. Finally, the improved EfficientNet network is further utilized as a pre-trained network to achieve tool wear state monitoring. Utilizing the powerful representation ability of the pre-trained model and the surface texture features of workpiece, the model can accurately identify and judge the wear degree of the tool. The tool experiment results show that the proposed tool wear monitoring method has achieved remarkable results with recognition accuracy of 97.77%. While other popular methods such as VGG19, ResNet50, and ResNet152, whose training accuracies are 95.66%, 96.37%, and 91.27%, respectively. The comparative results highlight the excellent performance of the proposed method in recognition rate, training time and generalization performance.

High-sensitivity optical fiber seawater temperature and pressure sensor with a low-error demodulation method

Using a single optical microfiber (OM) sensor for multi-parameter sensing can lead to significant demodulation error due to ill-conditioned matrices and nonlinear response characteristics. To address these issues, this paper proposes a novel specially packaged optical microfiber coupler combined with a silver mirror (OMCM). OMCM is combined with a mechanically enhanced sensitivity fiber Bragg grating (FBG) to form a temperature-pressure sensor. The temperature sensitivity exceeds -1.7 nm/°C while the pressure sensitivity reaches 53.435 nm/MPa, with a depth resolution of 0.935 cm. According to the characteristics of the sensor spectrum, this paper proposes a new demodulation method, which combines machine learning methods with a traditional wavelength-tracking method to achieve low demodulation error. For temperature and pressure, the mean absolute percentage errors are 0.04% and 1.31%, respectively. This feature facilitates the detection of minute changes in shallow marine environments, lacustrine systems, and other aquatic habitats, thus making it highly suitable for applications such as underwater aquaculture and marine monitoring.

3D Terahertz Confocal Imaging with Chromatic Metasurface

AbstractTerahertz confocal imaging allows 3D see‐through of a non‐metallic object with high resolution. Conventional methods acquiring 3D images of thick objects suffer from limited depth‐of‐field, constrained depth resolution, and/or inconsistent spatial resolution at different depths. To address these limitations, the intrinsic chromatic aberration of a typical focusing metasurface is exploited to achieve frequency‐dependent focal lengths. An object located within this extended focal range can be readily 3D inspected by performing 2D raster scans. A rigorous analysis reveals that the focal spot maintains a constant waist diameter of 2.4 mm (equivalent to 2.2 at 275 GHz) and migrates 68.1 mm (equivalent to 62.4, or 16.4 times of Rayleigh length, or 1.4‐fold of the designed focal length at 275 GHz) from 175 to 525 GHz, and thus achieving a consistent spatial resolution and a large depth‐of‐field for 3D imaging. Importantly, this large depth‐of‐field is achieved with a relatively high numerical aperture of around 0.42. Measurements conducted between 220 and 330 GHz exhibit close agreement with the calculation. To demonstrate its imaging functionality, two stacked papers with different texts, a mobile phone, and earphones concealed in a charging case are imaged, where a short‐time Fourier transform is implemented in the time‐domain terahertz images to enhance image contrast. The presented metasurface is technologically significant for imaging systems to rapidly inspect objects in 3D with exceptional resolutions. Its potential applications include in‐situ defect detection and object identification in security screening.

Near-isotropic sub-Ångstrom 3d resolution phase contrast imaging achieved by end-to-end ptychographic electron tomography

Abstract Three-dimensional atomic resolution imaging using transmission electron microscopes is a unique capability that requires challenging experiments. Linear electron tomography methods are limited by the missing wedge effect, requiring a high tilt range. Multislice ptychography can achieve deep sub-Ångstrom resolution in the transverse direction, but depth resolution is limited to 2 to 3 nanometers. In this paper, we propose and demonstrate an end-to-end approach to reconstructing the electrostatic potential volume of the sample directly from the 4D-STEM datasets. End-to-end multislice ptychographic tomography recovers several slices at each tomography tilt angle and compensates for the missing wedge effect. The algorithm is initially tested in simulation with a Pt@Al2O3 core–shell nanoparticle, where both heavy and light atoms are recovered in 3D from an unaligned 4D-STEM tilt series with a restricted tilt range of 90 degrees. We also demonstrate the algorithm experimentally, recovering a Te nanoparticle with sub-Ångstrom resolution.

Tm3+-Based Downshifting Nanoprobes with Enhanced Luminescence at 1680 nm for In Vivo Vascular Growth Monitoring.

Optical imaging in the 1500-1700 nm region, known as near-infrared IIb (NIR-IIb), shows potential for noninvasive in vivo detection owing to its ultrahigh tissue penetration depth and spatiotemporal resolution. Rare earth-doped nanoparticles have emerged as widely used NIR-IIb probes because of their excellent optical properties. However, their downshifting emissions rarely exhibit sufficient brightness beyond 1600 nm. This study presents tetragonal-phase thulium-doped nanoparticles (Tm3+-NPs) with core-shell-shell structures (CSS, LiYbF4:3%Tm@LiYbF4@LiYF4) that exhibit bright downshifting luminescence at 1680 nm. Enhanced luminescence is attributed to (1) the promoted nonradiative relaxation between the doping ions and (2) the maximized sensitization process. Additionally, this strategy was validated for NIR-IIb luminescence enhancement of erbium (Er3+)-doped NPs. After surface modification with PEGylated liposomes, tetragonal-phase Tm3+-NPs exhibited a prolonged blood cycle time, high colloidal stability, and good biocompatibility. Owing to the advantages of Tm3+-based probes in NIR-IIb imaging, in vivo thrombus detection and monitoring of angiogenesis and arteriogenesis were successfully performed in a mouse model of ischemic hind limbs.

Mechanical Characterization of Main Minerals in Carbonate Rock at the Micro Scale Based on Nanoindentation

The mechanical characterization of carbonate rock is crucial for the development of a hydrocarbon reservoir and underground gas storage. As a kind of natural composite material, the mechanical properties of carbonate rock exhibit multiscale characteristics. The macroscopic mechanical properties of carbonate rock are determined by the mineral composition and structure at the micro scale. To achieve a mechanical investigation at the micro scale, this study designed a scheme for micromechanical characterization of carbonate rock. First, scanning electron microscope observation and energy dispersive spectroscopy analysis were combined to select the appropriate micromechanical test areas and to identify the mineral types in each area. Second, the selected test area was positioned in the nanoindentation instrument through the comparison of different-type microscopic images. Finally, quasi-static nanoindentation was carried out on the surface of different minerals in the selected test area to obtain quantitative mechanical evaluation results. A typical carbonate rock sample from the Huangcaoxia gas storage was investigated in this study. The experimental results indicated apparent micromechanical heterogeneity in the carbonate rock. The Young’s modulus of pyrite was over 200 GPa, while that of clay minerals was only approximately 50 GPa. In addition, the proposed micromechanical characterization scheme was discussed based on experimental results. For minerals with an unknown Poisson’s ratio, the maximum error introduced by the 0.25 assumption was lower than 15%. To discuss the effectiveness of the nanoindentation results, the characterization abilities constituted by lateral spatial resolution and elastic response depth were analyzed. The analysis results revealed that the nanoindentation measurement of clay was more susceptible to influence by the surrounding environment as compared to other kinds of minerals with the experimental setup in this study. The micromechanical characterization scheme for clay minerals can be optimized in future research. The mechanical data obtained at the micro scale can be used for the interpretation of the macroscopic mechanical features of carbonate rock for the parameter input and validation of mineral-related simulation and for the construction of a mechanical upscaling model.

Near infrared‐II light‐sheet microscopy: Basic principle, intellectualization, and medical application

AbstractFluorescence microscopy has emerged as a pivotal tool in biological and medical research, wherein the assessment of penetration depth and imaging resolution serves as crucial indicators of a microscope's efficacy. However, the intricate interaction between photons and biological tissues gives rise to substantial background noise, presenting a formidable challenge. Fortunately, the near‐infrared window (NIR), particularly the NIR‐II range (1000–1700 nm), has emerged as a viable solution to mitigate these challenges and attain optimal imaging outcomes. This review centers on the progressive developments in light‐sheet microscopy techniques, elucidating their distinctive characteristics and applications in the field of biological imaging. Furthermore, the incorporation of optical design enhancements, encompassing light‐sheet microscopy is discussed as a pivotal strategy to augment imaging quality. The discussion extends to include refinements in imaging precision and the integration of deep learning methodologies with NIR imaging, especially for unique applications in NIR clinical exploration. The ensuing discourse endeavors to furnish a comprehensive synthesis of advancements in fluorescence microscopy, emphasizing the significance of the NIR windows, while also elucidating the role of sophisticated optical design and machine learning methodologies in enhancing overall imaging capabilities.

The NanoSIMS-HR: The Next Generation of High Spatial Resolution Dynamic SIMS.

The high lateral resolution and sensitivity of the NanoSIMS 50 and 50L series of dynamic SIMS instruments have enabled numerous scientific advances over the past 25 years. Here, we report on the NanoSIMS-HR, the first major upgrade to the series, and analytical tests in a suite of sample types, including an aluminum sample containing silicon crystals, microalgae, and plant roots colonized with a symbiotic fungus. Significant improvements have been made in the Cs+ ion source, high voltage (HV) control, stage reproducibility, and other aspects of the instrument that affect performance. The modified design of the NanoSIMS-HR thermal-ionization Cs+ source enables a 5 pA primary ion beam to be focused into a 100 nm spot, a ∼2.5-fold increase compared to Cs+ sources on previous instruments (∼2 pA at 100 nm). The brightness of the new Cs+ source enables an ultimate lateral resolution as high as 30 nm and improved detection limits for a given analysis area. Sample stage movement accuracy is higher than 500 nm, enabling many-fold higher throughput automated analyses. With the new HV control, the primary ion beam impact energy can be reduced from 16 to 2 keV, which enables higher depth resolution during depth profiling (a 2-fold improvement), albeit with a 5-fold decrease in lateral resolution. In the NanoSIMS-HR, the secondary ion column and detection system are identical to those used in the previous series, and the isotopic analysis performance is as precise as in previous NanoSIMS instruments.

Measurement of proton elastic scattering cross-section of Zr and deuterium distribution in thick ZrDx films

To precisely quantify the deuterium (D) concentration at significant depths and enhance the understanding of D distribution in zirconium (Zr) films, the proton elastic scattering cross-section of Zr was measured on an Au/Zr/Ti thin film. The measurement was conducted at laboratory angles of 165° and 170° over an energy range of 1.5–5.0 MeV. Non-Rutherford scattering was observed at proton energies exceeding 4.43 MeV. By combining proton backscattering (PBS) and nuclear reaction analysis (NRA) at different energies, a highly precise quantification of D concentrations within deuterated zirconium film, with depth resolution below 500 nm, was achieved. Additionally, we established initial assessments of Zr, Mo, and D atom concentrations in the ZrDx/Mo film, laying the groundwork for future studies.

Viscocohesive hyaluronan gel enhances stability of intravital multiphoton imaging with subcellular resolution.

Multiphoton microscopy (MPM) has become a preferred technique for intravital imaging deep in living tissues with subcellular detail, where resolution and working depths are typically optimized utilizing high numerical aperture, water-immersion objectives with long focusing distances. However, this approach requires the maintenance of water between the specimen and the objective lens, which can be challenging or impossible for many intravital preparations with complex tissues and spatial arrangements. We introduce the novel use of cohesive hyaluronan gel (HG) as an immersion medium that can be used in place of water within existing optical setups to enable multiphoton imaging with equivalent quality and far superior stability. We characterize and compare imaging performance, longevity, and feasibility of preparations in various configurations. This combination of HG with MPM is highly accessible and opens the doors to new intravital imaging applications.

Surface Wetting Properties of Lithium Anode Characterized Using Laser Scanning Confocal Microscopy

Surface wettability between the lithium metal anode and liquid electrolyte is a critical performance characteristic. Poor wettability can result in nonuniform stripping and deposition of lithium metal, nonuniform SEI formation, formation of dead lithium and; thus, shorter cycle life. Imaging techniques such as laser-induced fluorescence imaging using laser scanning confocal microscopy (LSCM), have become a valuable tool for investigating the surface properties of lithium metal anodes.1 Laser scanning confocal microscopy is an advanced microscopy technique that allows improved depth resolution relative to traditional optical microscopy.Arcadium Lithium Corporation has developed LIOVIX®printable lithium technology, a formulation that can be printed, at industrial speed, on most common substrates, such as Cu foil to produce thin lithium metal foil with thickness in the range of 5 µm to 50 µm with no limitation in width.2 LIOVIX®-based lithium film has a different microstructure when compared to a commercial foil (Figures 1a and 1b). LIOVIX-based thin foil retains rheology modifiers used in the formulation that serve as a 3D skeleton. This unique structure can change lithium metal surface plating behavior. Therefore, the 3D structure might mitigate the growth of dendritic lithium, reduce mechanical degradation, and improve safety and cycle life of the battery.LSCM was used for in-situ, in operando observations of the difference in surface properties and wettability properties of commercial lithium foil and LIOVIX-based lithium foil (Figures 1c and 1d). Lithium metal surface is dynamic and prone to forming various structures and compounds, depending on the conditions it is exposed to. The results showed that LIOVIX-based foil lithium activity is more homogenous and had a shallower interaction when compared to the commercial lithium foil. This potentially signifies more uniformity to the lithium activity in LIOVIX-based foil vs. commercial lithium foil; thus, more uniform surface activity within a battery system.Reference Nishikawa et al., 2010 J. Electrochem. Soc. 157 A1212Yakovleva et al., Battery utilizing printable lithium, U.S. Patent 11, 824, 182, B2, Nov. 21, 2023 Figure 1. Microscope image of A) LIOVIX® -based lithium foil (20um), B) commercial lithium foil (20um); and 3D Confocal microscope images of C) LIOVIX®-based lithium foil (20um) and D) commercial lithium foil (20um). Figure 1

Depth-resolved imaging through scattering media using time-gated light field tomography.

We present a novel, to the best of our knowledge, approach to overcome the limitations imposed by scattering media using time-gated light field tomography. By integrating the time-gating technique with light field imaging, we demonstrate the ability to capture and reconstruct images with different depths through highly scattering environments. Our method exploits the temporal characteristics of light propagation to selectively isolate ballistic photons, enabling enhanced depth resolution and improved imaging quality. Through comprehensive experimental validation and analysis, we showcase the effectiveness of our technique in resolving depth information with high fidelity, even in the presence of significant scattering. The resultant system can simultaneously acquire multi-angled projections of the object without requiring prior knowledge of the media or the target. This advancement holds promise for a wide range of applications, including non-invasive medical imaging, environmental monitoring, and industrial inspection, where imaging through scattering media is critical for an accurate and reliable analysis.

Advances in Lanthanide-Based NIR-IIb Probes for In Vivo Biomedical Imaging.

The past decades have witnessed the significant development and practical interest of in vivo biomedical imaging technologies and optical materials in the second-near infrared (NIR-II, 1000-1700 nm) window. Imaging with the extended emission wavelength toward the long-wavelength end (NIR-IIb, 1500-1700 nm) further offers micrometer imaging resolution and centimeter tissue penetration depth by taking advantage of the much-reduced photon scattering and near-zero tissue autofluorescence background, which have become a very hot research area. This review focuses on the recent advances in the development of lanthanide-based NIR-IIb probes for in vivo biomedical applications. The progress including ratiometric imaging, multiplexed imaging for wide-field and microscopy, lifetime multiplexing and sensing, persistent luminescence, and multimodal imaging is summarized. Challenges and future directions concerning the investigation of the photophysical and photochemical properties of NIR-IIb probes, the selection of near-infrared cameras as well as the potential extension of the NIR-IIb imaging sub-window are pointed out. This review will inspire readers who have a strong interest in developing optical imaging technology and long-wavelength fluorescence probes for high-contrast in vivo biomedical applications.

Laser ablation inductively coupled plasma mass spectrometry measurements for high-resolution chemical ice core analyses with a first application to an ice core from Skytrain Ice Rise (Antarctica)

Abstract. Conventional methods of inorganic impurity analysis do not provide high enough depth resolution for many scientific questions in ice core science. In this study, we present a setup of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for high-resolution glacier ice impurity analysis to the sub-millimetre scale. This setup enables ice core chemical impurity analysis to a depth resolution of ∼182 µm while consuming only very small amounts of ice. The system performs simultaneous analysis of sodium, magnesium and aluminium incorporated in the ice matrix. In this case study within the framework of the WACSWAIN (WArm Climate Stability of the West Antarctic Ice Sheet in the last INterglacial) project, our method is applied to a selection of samples from the Skytrain ice core (West Antarctica) over a total length of 6.7 m consisting of about 130 single samples. The main goal of this study is to use the new LA-ICP-MS method to extract meaningful climate signals on a depth resolution level beyond the limits of continuous-flow analysis (CFA). A comparison between low-resolution CFA data and the high-resolution LA-ICP-MS data reveals generally good agreement on the decimetre scale. Stacking of parallel laser measurements together with frequency analysis is used to analyse the high-resolution LA-ICP-MS data at millimetre resolution. Spectral analysis reveals that despite effects of impurity accumulation along ice crystal grain boundaries, periodic concentration changes in the Skytrain ice core on the millimetre scale can be identified in ice from 26.8 ka (kiloyears before present, i.e. 1950 CE). These findings open new possibilities for climate data interpretation with respect to fast changes in the last glacial period and beyond, for example within the Beyond EPICA oldest-ice project.

Fundamental effects of array density and modulation frequency on image quality of diffuse optical tomography.

Diffuse optical tomography (DOT) provides three-dimensional image reconstruction of chromophore perturbations within a turbid volume. Two leading strategies to optimize DOT image quality include, (i) arrays of regular, interlacing, high-density (HD) grids of sources and detectors with closest spacing less than 15mm, or (ii) source modulated light of order ∼100MHz. However, the general principles for how these crucial design parameters of array density and modulation frequency may interact to provide an optimal system design have yet to be elucidated. Herein, we systematically evaluated how these design parameters effect image quality via multiple key metrics. Specifically, we simulated 32 system designs with realistic measurement noise and quantified localization error, spatial resolution, signal-to-noise, and localization depth of field for each of ∼85000 point spread functions in each model. We found that array density had a far stronger effect on image quality metrics than modulation frequency. Additionally, model fits for image quality metrics revealed that potential improvements diminish with regular arrays denser than 9mm closest spacing. Further, for a given array density, 300MHz source modulation provided the deepest reliable imaging compared to other frequencies. Our results indicate that both array density and modulation frequency affect the spatial sampling of tissue, which asymptotically saturates due to photon diffusivity within a turbid volume. In summary, our results provide comprehensive perspectives for optimizing future DOT system designs in applications from wearable functional brain imaging to breast tumor detection.

Ultrathin visible-light OCT endomicroscopy for in vivo ultrahigh-resolution neuroimaging in deep brain

Deep-brain neuroimaging, a task that demands high-resolution imaging techniques for visualizing intricate brain structures, assessing deep-seated disease histopathology, and offering real-time intervention guidance, is challenged by the resolution-depth trade-off of current methods. We propose an optical coherence tomography (OCT) endomicroscopy device for high-resolution in vivo imaging of deep brain microstructures and histopathology. A unique liquid shaping technique enables the direct fabrication of a microlens on the fiber tip of the imaging probe, optimizing imaging performance parameters, such as longitudinal focal shift, focused spot size, and working distance. In addition, a broadband visible-light source enhances axial resolution and OCT imaging contrast. As a result, the first monolithic visible-light OCT (vis-OCT) endomicroscope, with a submillimeter outer diameter (∼0.4 mm), is presented, achieving an ultrahigh resolution of 1.4 μm axial × 4.5 μm transverse in air. This compact probe allows minimally invasive in vivo deep-brain imaging in mice at a depth of 7.2 mm. Key regions in the mouse deep brain, such as the isocortex, corpus callosum, and caudate putamen, were successfully identified using our vis-OCT endomicroscope. In addition, we examined the myeloarchitectures and cytoarchitectures in the isocortex. Our findings demonstrate that the vis-OCT endomicroscope offers enhanced visualization of myelinated axon fibers and nerve fiber bundles compared to its 800 nm counterpart. This vis-OCT endomicroscope, overcoming resolution and imaging depth limitations of conventional methods, offers a novel tool for minimally invasive, ultrahigh-resolution in vivo deep brain neuroimaging.

Estimation of the depth-variant seismic wavelet based on the modified unscaled S-transform

Seismic inversion is one of the key techniques used for reservoir characterization. Depth-domain seismic inversion eliminates the cumulative errors associated with depth-to-time and time-to-depth conversions, thus providing geologists and reservoir engineers with an intuitive basis for geological interpretation. The method has received increasing attention in the field of reservoir characterization. Extracting accurate depth-domain seismic wavelets is a prerequisite for successful depth-domain seismic inversion. However, the depth-domain wavelet is velocity-dependent and exhibits significant non-stationarity, which leads to the failure of seismic wavelet estimation methods based on the stationary convolutional model. To this end, we propose a modified wavenumber-domain unscaled S-transform (MWUST) method to accomplish accurate estimation of depth-domain seismic wavelets. The proposed method enhances the accuracy of wavenumber components by removing the linear wavenumber-dependent term from the S-transform. Furthermore, it introduces slope and intercept parameters to improve the depth resolution at low wavenumbers, thereby yielding a more reliable depth–wavenumber spectrum. Subsequently, the relationship between the non-stationary depth-domain seismic wavelet and the depth–wavenumber spectrum is established, allowing for the accurate extraction of non-stationary wavelets under the assumption that the depth-domain reflectivity is a random sequence. Synthetic and real data applications have been used to verify the effectiveness of the proposed method.

Soft wearable electronics for evaluation of biological tissue mechanics

Flexible wearable devices designed to evaluate the biomechanical properties of deep tissues not only facilitate continuous and effective monitoring in basic performance but also exhibit significant potential in broader disease assessments. Recent advancements are highlighted in the structural and principled design of platforms capable of capturing various biomechanical signals. These advancements have led to enhanced testing capabilities concerning spatial scales and resolution modes at different depths. This review discusses the engineering of soft wearable devices for the biomechanical evaluation of deep tissue signals. It encompasses different measurement modes, device design and fabrication methods, integrated circuit (IC) integration schemes, and the characteristics of measurement depth and accuracy. The core discussion focuses on platform development, targeting different monitoring sites and platform structure design, ranging from linear strain gauges and conformal stretchable sensors to complex three-dimensional (3D) circuit-integrated stretchable arrays. We further explore various technologies associated with different measurement mechanisms and engineering designs, as well as the penetration depth and spatial resolution of these wearable sensors. The practical applications of these technologies are evident in the monitoring of deep tissue signals and changes in tissue characteristics. The results suggest that wearable biomechanical sensing systems hold substantial promise for applications in healthcare and research.

Three-dimensional isotropic imaging of live suspension cells enabled by droplet microvortices

Fast, nondestructive three-dimensional (3D) imaging of live suspension cells remains challenging without substrate treatment or fixation, precluding scalable single-cell morphometry with minimal alterations. While optical sectioning techniques achieve 3D live cell imaging, lateral versus depth resolution differences further complicate analysis. We present a scalable microfluidic method capable of 3D fluorescent isotropic imaging of live, nonadherent cells suspended inside picoliter droplets with high-speed single-cell volumetric readout (800 to 1,200 slices in 5 to 8 s) and near-diffraction limit resolution (~216 nm). The platform features a droplet trap array that leverages flow-induced droplet interfacial shear to generate intradroplet microvortices, which rotate single cells on their axis to enable optical projection tomography (OPT)-based imaging. This allows gentle (~1 mPa shear stress) observation of cells encapsulated inside nontoxic isotonic buffer droplets, facilitating scalable OPT acquisition by simultaneous spinning of hundreds of cells. We demonstrate 3D imaging of live myeloid and lymphoid cells in suspension, including K562 cells, as well as naive and activated T cells-small cells prone to movement in their suspended phenotype. Our fully suspended, orientation-independent cell morphometry, driven by isotropic imaging and spherical harmonic analysis, enabled the study of primary T cells across various immunological activation states. This approach unveiled six distinct nuclear content distributions, contrasting with conventional 2D images that typically portray spheroid and bean-like nuclear shapes associated with lymphocytes. Our arrayed-droplet OPT technology is capable of isotropic, single live-cell 3D imaging, with the potential to perform large-scale morphometry of immune cell effector function states while providing compatibility with microfluidic droplet operations.

Achieving coaxial photoacoustic/ultrasound dual-modality imaging by high-performance Sm: 0.72PMN-0.28PT transparent piezoelectric ceramic

As a promising new medical imaging method, photoacoustic imaging (PAI) has the advantages of optical resolution and acoustic depth of penetration. The transparent ultrasound transducer (TUT), as a novel device applied to PAI, can combine the laser and acoustic beam coaxially to improve the imaging quality. Transparent piezoelectric materials are the key to developing piezoelectric TUTs. However, due to the birefringence and light scattering caused by ferroelectric domains, it is very hard to prepare transparent piezoelectric materials with both high optical transmittance and excellent piezoelectricity. In this study, 2.5 mol% Sm-doped 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) ceramic with a piezoelectric coefficient d33 of 1460 pC N−1 and an optical transmission of 69 % at Near-Infrared (NIR) is successfully prepared, and its optical, microstructure, ferroelectric and dielectric properties are fully studied. Subsequently, a 3 mm-diameter photoacoustic coaxial probe is fabricated, involving a transparent ultrasound transducer based on the prepared ceramic. The TUT has a center frequency (fc) of 18.5 MHz, a −6 dB bandwidth of 20 %, and a high effective electromechanical factor (keff) of 0.62. In addition, the imaging capability of the miniature probe is firstly confirmed through photoacoustic/ultrasound dual-modality imaging of in-vivo animals and phantoms, which indicates that the proposed transparent piezoelectric ceramic has great potential for PA/US imaging.