The virtual staining method by quantitative phase imaging for label free lymphocytes based on self-supervised iteration cycle-consistent adversarial networks.

Quantitative phase imaging (QPI) provides 3D structural and morphological information for label free living cells. Unfortunately, this quantitative phase information cannot meet doctors' diagnostic requirements of the clinical "gold standard," which displays stained cells' pathological states based on 2D color features. To make QPI results satisfy the clinical "gold standard," the virtual staining method by QPI for label free lymphocytes based on self-supervised iteration Cycle-Consistent Adversarial Networks (CycleGANs) is proposed herein. The 3D phase information of QPI is, therefore, trained and transferred to a kind of 2D "virtual staining" image that is well in agreement with "gold standard" results. To solve the problem that unstained QPI and stained "gold standard" results cannot be obtained for the same label free living cell, the self-supervised iteration for the CycleGAN deep learning algorithm is designed to obtain a trained stained result as the ground truth for error evaluation. The structural similarity index of our virtual staining experimental results for 8756 lymphocytes is 0.86. Lymphocytes' area errors after converting to 2D virtual stained results from 3D phase information are less than 3.59%. The mean error of the nuclear to cytoplasmic ratio is 2.69%, and the color deviation from the "gold standard" is less than 6.67%.

Imaging the intracellular refractive index distribution (IRID) for dynamic label-free living colon cancer cells via circularly depolarization decay model (CDDM).

Label-free detection of intracellular substances for living cancer cells remains a significant hurdle in cancer pathogenesis research. Although the sensitivity of light polarization to intracellular substances has been validated, current studies are predominantly focused on tissue lesions, thus label-free detection of substances within individual living cancer cells is still a challenge. The main difficulty is to find specific detection methods along with corresponding characteristic parameters. With refractive index as an endogenous marker of substances, this study proposes a detection method of intracellular refractive index distribution (IRID) for label-free living colon cancer (LoVo) cells. Utilizing the circular depolarization decay model (CDDM) to calculate the degree of circular polarization (DOCP) modulated by the cell allows for the derivation of the IRID on the focal plane. Experiments on LoVo cells demonstrated the refractive index of single cell can be accurately and precisely measured, with precision of 10-3 refractive index units (RIU). Additionally, chromatin content during the interphases (G1, S, G2) of cell cycle was recorded at 56.5%, 64.4%, and 71.5%, respectively. A significantly finer IRID can be obtained compared to the phase measurement method. This method is promising in providing a dynamic label-free intracellular substances detection method in cancer pathogenesis studies.

Alternating projection combined with fast gradient projection (FGP-AP) method for intensity-only measurement optical diffraction tomography in LED array microscopy.

Optical diffraction tomography (ODT) is a powerful label-free measurement tool that can quantitatively image the three-dimensional (3D) refractive index (RI) distribution of samples. However, the inherent "missing cone problem," limited illumination angles, and dependence on intensity-only measurements in a simplified imaging setup can all lead to insufficient information mapping in the Fourier domain, affecting 3D reconstruction results. In this paper, we propose the alternating projection combined with the fast gradient projection (FGP-AP) method to compensate for the above problem, which effectively reconstructs the 3D RI distribution of samples using intensity-only images captured from LED array microscopy. The FGP-AP method employs the alternating projection (AP) algorithm for gradient descent and the fast gradient projection (FGP) algorithm for regularization constraints. This approach is equivalent to incorporating prior knowledge of sample non-negativity and smoothness into the 3D reconstruction process. Simulations demonstrate that the FGP-AP method improves reconstruction quality compared to the original AP method, particularly in the presence of noise. Experimental results, obtained from mouse kidney cells and label-free blood cells, further affirm the superior 3D imaging efficacy of the FGP-AP method.

Adsorption Behavior of Dissolved Gas Molecules in Transformer Oil on Rh Modified GeSe Monolayer.

Dissolved gas analysis in transformer oil is useful for detecting early transformer failures. The research on gas sensors for monitoring dissolved gas in transformer oil has attracted wide attention from academia and industry. In this study, Rh-doped GeSe monolayers were used as gas sensing materials based on the density functional theory (DFT). The potential of the Rh-GeSe monolayer as a gas sensor was evaluated by calculating the geometric structure, adsorption distance (dsub/gas), binding energy (Eb), adsorption energy (Eads), transfer charge (ΔQ), the density of states (DOS), band structure, electron localization function (ELF), charge difference density (CDD), and sensitivity (S) of Rh-GeSe monolayer with eight gas molecules (SO2, C2H2, NO2, H2, CH4, CO2, H2S, and CO). The results show that the Rh-GeSe monolayer has a prominent response to SO2, C2H2, and NO2 gas molecules and has great potential to become an excellent gas sensor. This study provides a theoretical basis for the application of Rh-GeSe monolayer in the field of gas sensing and provides a new way for the development of other gas sensors.

LED array microscopy system correction method with comprehensive error parameters optimized by phase smoothing criterion.

LED array microscopy is a novel computational imaging technique that can achieve two-dimensional (2D) phase imaging and three-dimensional (3D) refractive index imaging with both high resolution and a large field of view. Although its experimental setup is simple, the errors caused by LED array position and light source central wavelength obviously decrease the quality of reconstructed results. To solve this problem, comprehensive error parameters optimized by the phase smoothing criterion are put forward in this paper. The central wavelength error and 3D misalignment model with six freedom degree errors of LED array are considered as the comprehensive error parameters when the spatial positional and optical features of arbitrarily placed LED array are unknown. Phase smoothing criterion is also introduced to the cost function for optimizing comprehensive error parameters to improve the convergence results. Compared with current system correction methods, the simulation and experimental results show that the proposed method in this paper has the best reconstruction accuracy, which can be well applied to an LED array microscope system with unknown positional and optical features of the LED array.

Flexible dynamic quantitative phase imaging based on division of focal plane polarization imaging technique.

This paper proposes a flexible and accurate dynamic quantitative phase imaging (QPI) method using single-shot transport of intensity equation (TIE) phase retrieval achieved by division of focal plane (DoFP) polarization imaging technique. By exploiting the polarization property of the liquid crystal spatial light modulator (LC-SLM), two intensity images of different defocus distances contained in orthogonal polarization directions can be generated simultaneously. Then, with the help of the DoFP polarization imaging, these images can be captured with single exposure, enabling accurate dynamic QPI by solving the TIE. In addition, our approach gains great flexibility in defocus distance adjustment by adjusting the pattern loaded on the LC-SLM. Experiments on microlens array, phase plate, and living human gastric cancer cells demonstrate the accuracy, flexibility, and dynamic measurement performance for various objects. The proposed method provides a simple, flexible, and accurate approach for real-time QPI without sacrificing the field of view.

Association between the triglyceride glucose (TyG) index and the risk of acute kidney injury in critically ill patients with heart failure: analysis of the MIMIC-IV database.

BACKGROUND: Insulin resistance (IR) can be effectively assessed using the dependable surrogate biomarker triglyceride-glucose (TyG) index. In various critical care contexts, like contrast-induced acute kidney injury (AKI), an elevated TyG index has demonstrated a robust correlation with the incidence of AKI. Nonetheless, the potential of the TyG index to predict AKI in critically ill patients with heart failure (HF) remains uncertain. METHODS: A cohort of participants was non-consecutively selected from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database and divided into quartiles based on their TyG index values. The incidence of AKI was the primary outcome. The secondary endpoint was in-hospital mortality within both the whole study population and the subset of AKI patients. The use of the renal replacement therapy (RRT) which represented the progression of AKI severity was also included as a secondary endpoint representing renal outcome. A restricted cubic splines model and Cox proportional hazards models were utilized to evaluate the association of TyG index with the risk of AKI in patients with HF in a critical condition. Kaplan-Meier survival analysis was employed to estimate primary and secondary endpoint disparities across groups differentiated by their TyG index. RESULTS: This study included a total of 1,393 patients, with 59% being male. The incidence of AKI was 82.8%. Cox proportional hazards analyses revealed a significant association between TyG index and the incidence of AKI in critically ill patients with HF. The restricted cubic splines model illustrated the linear relationship between higher TyG index and increased risk of AKI in this specific patient population. Furthermore, the Kaplan-Meier survival analyses unveiled statistically significant differences in the use of RRT across the subset of AKI patients based on the quartiles of the TyG index. CONCLUSIONS: The results highlight the TyG index as a robust and independent predictor of the incidence of AKI and poor renal outcome in patients with HF in a critical condition. However, further confirmation of causality necessitates larger prospective studies.

MicroRNA-499-5p promotes vascular smooth muscle cell proliferation and migration via inhibiting SOX6.

Atherosclerosis (AS) is the primary etiology of cardiovascular disease, which is considered the leading cause of death all over the world. MicroRNA miR-499-5p was involved in the functional regulation of myocardial and skeletal muscle, whereas its role in atherosclerosis, especially in vascular smooth muscle cells (VSMCs), remains unclear. Our study aims to investigate the effects of miR-499-5p in the proliferation and migration of VSMCs and potential mechanisms. We used mouse aortic vascular smooth muscle cells (MOVAS) and ApoE-/- mice to establish the models of AS in vitro and in vivo, respectively. RT-PCR was performed to detect the expression level of miR-499-5p. Subsequently, Cell Counting Kit-8 (CCK-8) assays, Transwell assays, and wound-healing assays were used to evaluate cell proliferation and migration. Dual-luciferase reporter assay was performed to validate the interaction between miR-499-5p and SOX6. miR-499-5p significantly increased in aorta tissues of mice in AS tissues and vascular smooth muscle cells treated with ox-LDL. miR-499-5p overexpression could promote the proliferation and migration of MOVAS. Bioinformatics analysis predicted and further experiments verified that miR-499-5p could directly bind to the 3'-untranslated region (UTR) region of SOX6. Further, miR-499-5p induced an increased expression of smooth muscle proliferation and migration-related genes, PCNA, cyclin D1, and matrix metalloproteinase (MMP2), as well as the decreased expression of proliferation inhibiting factor p21, which was significantly reversed by SOX6 overexpression. miR-499-5p boosts the proliferation and migration of smooth muscle cells by binding and inhibiting SOX6 expression. The miR-499-5p/SOX6 axis may present a promising therapeutic implication for the prevention and treatment of cardiovascular diseases.

Accurate 3D morphological computational model reconstruction of suspended cells imaged through stratified media by the precise depth-varying point spread function method.

Accurate three-dimensional (3D) morphological computational models of cells are important in a number of biological studies. This study proposes a precise depth-varying point spread function (PDV-PSF) method for reconstructing 3D computational models of suspended cells from two-dimensional (2D) confocal image stacks. Our approach deblurs the 2D images in horizontal plane and corrects the deformation in vertical direction to overcome the refractive index mismatch problem caused by suspended cells imaging through stratified media. Standard fluorescent polystyrene spheres and Jurkat T-lymphocytes are selected to evaluate the validity and accuracy of this PDV-PSF method. Qualitative and quantitative results demonstrate that our approach has superior performance in 3D morphological computational models reconstruction of suspended cells.

Geomorphic response of outburst floods: Insight from numerical simulations and observations--The 2018 Baige outburst flood in the upper Yangtze River.

Outburst floods related to glacial or landslide damming are a major agent of geomorphic change in mountain rivers. Although the evidence between outburst flooding and riverine landscapes has been gradually recognized, the lack of hydraulics to the extent that there has still not been quantified on the relationship of how the amount and spatial distribution of these changes relate quantitatively to the hydraulic conditions and durations of these catastrophic events. This study combined remote and field observations of the 2018 Baige outburst flood with two-dimensional numerical simulation using the diffusive wave equation. By feeding the measured dam-breach hydrograph and comparing three different Manning coefficients in numerical experiments, the simulation results show that when n = 0.055, the time of peak flow was only 0.5 h different from that indicated by measured data in Yebatan, 54 km downstream of the Baige landslide dam. Under high shear stress over several hours at sustained ~20 m water depth, lateral erosion caused by these outburst floods contributed to the adjacent landslide, which was activated in association with intermittent water velocity waves of approximately 17 m/s. Sustained high stream power (>50 kW m2) from the outburst flood eroded slope toes and accelerated slippage of six slopes. Combining simulation and observations, we also developed a physical model related to hillslope instability caused by high hydrodynamic erosion of riverbanks generated by flow waves lasting several hours, which explained the hydrodynamic response of the outburst flood to the canyon geomorphology. Furthermore, we suggest that the pattern of channel widening erosion and deposition is governed by the variation in shear stress and Froude number as the high-energy flood flows from a wide channel into a narrow river valley. Our findings highlight that the hydraulics of high-magnitude outburst floods and sediment transport play crucial roles in reshaping canyon geomorphology.

Label-free biological sample detection and non-contact separation system based on microfluidic chip.

The detection and separation of biological samples are of great significance for achieving accurate diagnoses and state assessments. Currently, the detection and separation of cells mostly adopt labeling methods, which will undoubtedly affect the original physiological state and functions of cells. Therefore, in this study, a label-free cell detection method based on microfluidic chips is proposed. By measuring the scattering of cells to identify cells and then using optical tweezers to separate the target cells, the whole process without any labeling and physical contact could realize automatic cell identification and separation. Different concentrations of 15 µm polystyrene microspheres and yeast mixed solution are used as samples for detection and separation. The detection accuracy is over 90%, and the separation accuracy is over 73%.

Multichalcogen-Integrated Cathodes for Novel Lithium-Chalcogenide Batteries in Ether and Ester Electrolytes.

Lithium-sulfur (Li-S) batteries and lithium-selenium (Li-Se) batteries that contain only one single active element have unique advantages and disadvantages. Inspired by ternary lithium batteries, multielement chalcogenide compounds with integrated advantages may improve upon the performance of lithium-chalcogenide batteries at the source. In this work, activated carbon (AC) with an Al2O3@SiO2 heterojunction is used as the carrier, and the performances and mechanisms of elemental substances (X/AC, X = S, Se, and Te) are studied in ether and ester electrolytes as the basis for preparing multielement chalcogenide composites (SST/AC, SST: S-Se-Te compound). In the ester electrolyte system, SST811/AC (where S/Se/Te = 8:1:1, molar ratio) exhibited the best cycling performance, and the capacity remained at 1024.9 mA h g-1 after 300 cycles. The characterization results revealed the mechanisms and sequences of the gradual liquid-phase reactions of SST/AC in ether electrolytes and the direct solid-phase reactions in ester electrolytes. The active elements in SST/AC fully demonstrated their own functions, enabling the effective construction of new lithium-chalcogenide battery systems. This work provides inspiration for the subsequent research of multielement lithium-chalcogenide batteries and paves the way for their application.

Dilute Electrolyte to Mitigate Capacity Decay and Voltage Fading of Co-Free Li-Rich Cathode for Next-Generation Li-Ion Batteries.

Li-rich cathodes have potential for use in next-generation Li-ion batteries (LIBs) owing to their high specific capacity and low cost. However, their intrinsic cycling decay and voltage fading limit practical applications. In addition, these cathodes contain Co, which is nonrenewable, scarce, and expensive. This situation severely limits the rapid and sustainable development of low-cost LIBs. This paper introduces a novel dilute electrolyte to overcome these limitations based on the Co-free Li-rich Li1.2Mn0.54Ni0.26O2 (LMNO) cathode. An even and robust cathode-electrolyte interface (CEI) formed on the surface of LMNO further protects it from side reactions in the dilute electrolyte. This Co-free Li-rich cathode exhibits the best electrochemical performance reported to date among Li-rich cathodes in terms of outstanding cycling stability (capacity retention of 99.8% at 0.5 C) and dramatically suppressed voltage fading (only 0.3% after 100 cycles). This study demonstrates the potential of Co-free Li-rich cathodes for applications in next-generation LIBs.

Scattering Inversion Study for Suspended Label-Free Lymphocytes with Complex Fine Structures.

Objective and Impact Statement. Distinguishing malignant lymphocytes from normal ones is vital in pathological examination. We proposed an inverse light scattering (ILS) method for label-free suspended lymphocytes with complex fine structures to identify their volumes for pathological state. Introduction. Light scattering as cell's "fingerprint" provides valuable morphology information closely related to its biophysical states. However, the detail relationships between the morphology with complex fine structures and its scattering characters are not fully understood. Methods. To quantitatively inverse the volumes of membrane and nucleus as the main scatterers, clinical lymphocyte morphologies were modeled combining the Gaussian random sphere geometry algorithm by 750 reconstructed results after confocal scanning, which allowed the accurate simulation to solve ILS problem. For complex fine structures, the specificity for ILS study was firstly discussed (to our knowledge) considering the differences of not only surface roughness, posture, but also the ratio of nucleus to the cytoplasm and refractive index. Results. The volumes of membrane and nucleus were proved theoretically to have good linear relationship with the effective area and entropy of forward scattering images. Their specificity deviations were less than 3.5%. Then, our experimental results for microsphere and clinical leukocytes showed the Pearson product-moment correlation coefficients (PPMCC) of this linear relationship were up to 0.9830~0.9926. Conclusion. Our scattering inversion method could be effectively applied to identify suspended label-free lymphocytes without destructive sample pretreatments and complex experimental systems.

Designing conductive networks of hybrid carbon enables stable and long-lifespan cotton-fiber-based lithium-sulfur batteries.

In modern society, flexible rechargeable batteries have become a burgeoning apodictic choice for wearable devices. Conventional lithium-sulfur batteries lack sufficient flexibility because their electrode materials are too rigid to bend. Along with the inherent high theoretical capacity of sulfur, lithium-sulfur batteries have some issues, such as dissolution and shuttle effect of polysulfides, which restricts their efficiency and practicability. Here, a flexible and "dead-weight"-free lithium-sulfur battery substrate with a three-dimensional structure was prepared by a simple strategy. With the cooperative assistance of carbon nanotubes and graphene attached to cotton fibers, the lithium-sulfur battery with 2.0 mg cm-2 sulfur provided a high initial discharge capacity of 1098.7 mA h g-1 at 1C, and the decay rate after 300 cycles was only 0.046% per cycle. The initial discharge capacity at 2C was 872.4 mA h g-1 and the capacity was maintained 734.4 mA h g-1 after 200 cycles with only a 0.079% per cycle decay rate.

Stabilization of Li-Se Batteries by Wearing PAN Protective Clothing.

Lithium-selenium (Li-Se) batteries have recently attracted more and more attentions as new secondary battery systems due to the similarity but better performances than lithium-sulfur (Li-S) batteries. However, the dissolution of selenium in electrolytes results in low selenium utilization, concentration polarization, inferior capacities, and unstable cycling performances. Herein, 46.58 wt% of selenium is loaded on carbon cloths through the calcination process, which were directly used as self-supporting cathodes. Carbonized polyacrylonitrile (PAN) nanofiber membranes produced by electrospinning are worn as the protective clothing between the cathode and separator to avoid the loss and dissolution of selenium. The stabilization of Li-Se batteries was enhanced by introducing two interlayers, as expected, they exhibit a stable reversible average capacity of 590 mA h g-1 during 1000 cycles at a current density of 0.5 C (1 C = 675 mA g-1). No polyselenide formation is found during charging/discharging, and the effects of the introduced PAN interlayers on improving the stability and reducing the polarization of the assembled Li-Se batteries are confirmed by mechanistic characterizations. These regulated Li-Se batteries present great application potential in the future, and the design idea can also be promoted to explore other energy storage systems.

Measuring Mechanism and Applications of Polymer-Based Flexible Sensors.

A new type of flexible sensor, which could maintain the deformation consistency and achieve the real-time detection of the variation in load of the measured object, was proposed in this work. According to the principle of forced assembly, PDMS was used as the substrate of sensitive components and electrodes, while carbon fiber was added as a conductive medium to prepare a polymer-based flexible sensor, which effectively overcame the deformation limitation and output instability of conventional flexible sensors due to different substrates of sensitive components and the electrode. Combined with the sensor structure and the forced assembly method, a theoretical analysis of its conductive measurement mechanism was carried out. Meanwhile, an experimental test device was designed to test and analyze the output characteristics of the flexible sensor under a static and dynamic alternating load. The results show that the flexible sensor exhibited linear output under the dynamic alternating load of 10 kN to 60 kN and frequency of 3 Hz. Peak and valley value had the same phase with the load extremes. The dynamic and static experiments show that the resistance output signal and the sensitivity was in the range of 310~624.15 Ω and 171⁻183 N/Ω respectively. However, due to the hysteresis of the elastic recovery of the polymer, the output repeatability of the flexible sensor under the dynamic alternating load was 5.03% and 0.78% lower than that of the static load, respectively. Combined with the static and dynamic experiments, it was verified that the polymer-based flexible sensor can maintain the same deformation characteristics with the measured object, and at the same time outputted a resistance signal with a certain mapping relationship with the applied load. The repeatability of the output signal under dynamic and static experiments was within ±7%, which can meet the measurement requirements of the fatigue life of the measured body during periodic load.

Polar Transversal Initial Alignment Algorithm for UUV with a Large Misalignment Angle.

The conventional initial alignment algorithms are invalid in the polar region. This is caused by the rapid convergence of the Earth meridians in the high-latitude areas. However, the initial alignment algorithms are important for the accurate navigation of Unmanned Underwater Vehicles. The polar transversal initial alignment algorithm is proposed to overcome this problem. In the polar transversal initial alignment algorithm, the transversal geographic frame is chosen as the navigation frame. The polar region in the conventional frames is equivalent to the equatorial region in the transversal frames. Therefore, the polar transversal initial can be effectively applied in the polar region. According to the complex environment in the polar region, a large misalignment angle is considered in this paper. Based on the large misalignment angle condition, the non-linear dynamics models are established. In addition, the simplified unscented Kalman filter (UKF) is chosen to realize the data fusion. Two comparison simulations and an experiment are performed to verify the performance of the proposed algorithm. The simulation and experiment results indicate the validity of the proposed algorithm, especially when large misalignment angles occur.

Polar Cooperative Navigation Algorithm for Multi-Unmanned Underwater Vehicles Considering Communication Delays.

To solve the navigation accuracy problems of multi-Unmanned Underwater Vehicles (multi-UUVs) in the polar region, a polar cooperative navigation algorithm for multi-UUVs considering communication delays is proposed in this paper. UUVs are important pieces of equipment in ocean engineering for marine development. For UUVs to complete missions, precise navigation is necessary. It is difficult for UUVs to establish true headings because of the rapid convergence of Earth meridians and the severe polar environment. Based on the polar grid navigation algorithm, UUV navigation in the polar region can be accomplished with the Strapdown Inertial Navigation System (SINS) in the grid frame. To save costs, a leader-follower type of system is introduced in this paper. The leader UUV helps the follower UUVs to achieve high navigation accuracy. Follower UUVs correct their own states based on the information sent by the leader UUV and the relative position measured by ultra-short baseline (USBL) acoustic positioning. The underwater acoustic communication delay is quantized by the model. In this paper, considering underwater acoustic communication delay, the conventional adaptive Kalman filter (AKF) is modified to adapt to polar cooperative navigation. The results demonstrate that the polar cooperative navigation algorithm for multi-UUVs that considers communication delays can effectively navigate the sailing of multi-UUVs in the polar region.