Kilohertz volumetric imaging of in-vivo dynamics using squeezed light field microscopy.

Volumetric functional imaging of transient cellular signaling and motion dynamics poses a significant challenge to current microscopy techniques, primarily due to limitations in hardware bandwidth and the restricted photon budget within short exposure times. In response to this challenge, we present squeezed light field microscopy (SLIM), a computational imaging method that enables rapid detection of high-resolution three-dimensional (3D) light signals using only a single, low-format camera sensor area. SLIM pushes the boundaries of 3D optical microscopy, achieving over one thousand volumes per second across a large field of view of 550 µm in diameter and 300 µm in depth. Using SLIM, we demonstrated blood cell velocimetry across the embryonic zebrafish brain and in a free-moving tail exhibiting high-frequency swinging motion. The millisecond temporal resolution also enables accurate voltage imaging of neural membrane potentials in the leech ganglion. These results collectively establish SLIM as a versatile and robust imaging tool for high-speed microscopy applications.

Correction: Critical role of hydrogen bonding between microcrystalline cellulose and g-C3N4 enables highly efficient photocatalysis.

Correction for 'Critical role of hydrogen bonding between microcrystalline cellulose and g-C3N4 enables highly efficient photocatalysis' by Zhaoqiang Wang et al., Chem. Commun., 2024, 60, 204-207, https://doi.org/10.1039/D3CC04800D.

Critical role of hydrogen bonding between microcrystalline cellulose and g-C3N4 enables highly efficient photocatalysis.

Developing a highly efficient photocatalyst for energy and environmental applications is urgently required. Herein, graphitic carbon nitride (CN) coupled with microcrystalline cellulose (MCC) (denoted as MCC-X/CN) shows excellent photocatalytic performance for tetracycline (TC) degradation and H2 evolution. And the optimized MCC-0.05/CN shows an improved TC degradation rate (Kapp = 0.019 min-1) and H2 evolution rate (642.71 µmol g-1 h-1), which are 1.9 and 22 times higher than those of pure CN, respectively. This improvement primarily results from hydrogen bonding (H-bonding) between CN and MCC, which enables excellent charge separation and migration, leading to the outstanding photoelectrochemical properties of MCC-0.05/CN.

Coded aperture snapshot hyperspectral light field tomography.

Multidimensional imaging has emerged as a powerful technology capable of simultaneously acquiring spatial, spectral, and depth information about a scene. However, existing approaches often rely on mechanical scanning or multi-modal sensing configurations, leading to prolonged acquisition times and increased system complexity. Coded aperture snapshot spectral imaging (CASSI) has introduced compressed sensing to recover three-dimensional (3D) spatial-spectral datacubes from single snapshot two-dimensional (2D) measurements. Despite its advantages, the reconstruction problem remains severely underdetermined due to the high compression ratio, resulting in limited spatial and spectral reconstruction quality. To overcome this challenge, we developed a novel two-stage cascaded compressed sensing scheme called coded aperture snapshot hyperspectral light field tomography (CASH-LIFT). By appropriately distributing the computation load to each stage, this method utilizes the compressibility of natural scenes in multiple domains, reducing the ill-posed nature of datacube recovery and achieving enhanced spatial resolution, suppressed aliasing artifacts, and improved spectral fidelity. Additionally, leveraging the snapshot 3D imaging capability of LIFT, our approach efficiently records a five-dimensional (5D) plenoptic function in a single snapshot.

Augmented light field tomography through parallel spectral encoding.

Snapshot recording of transient dynamics in three dimensions (3-D) is highly demanded in both fundamental and applied sciences. Yet it remains challenging for conventional high-speed cameras to address this need due to limited electronic bandwidth and reliance on mechanical scanning. The emergence of light field tomography (LIFT) provides a new solution to these long-standing problems and enables 3-D imaging at an unprecedented frame rate. However, based on sparse-view computed tomography, LIFT can accommodate only a limited number of projections, degrading the resolution in the reconstructed image. To alleviate this problem, we herein present a spectral encoding scheme to significantly increase the number of allowable projections in LIFT while maintaining its snapshot advantage. The resultant system can record 3-D dynamics at a kilohertz volumetric frame rate. Moreover, by using a multichannel compressed sensing algorithm, we improve the image quality with an enhanced spatial resolution and suppressed aliasing artifacts.

WRKY29 transcription factor regulates ethylene biosynthesis and response in arabidopsis.

The gaseous phytohormone ethylene participates in a lot of physiological processes in plants. 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS, EC 4.4.1.14) and the ACC oxidase (ACO, EC 1.14.17.4) are key enzymes in ethylene biosynthesis. However, how ACSs and ACOs are regulated at the transcriptional level is largely unknown. In the present study, we showed that an Arabidopsis (Arabidopsis thaliana) WRKY-type transcription factor (TF), WRKY29 positively regulated the expression of ACS5, ACS6, ACS8, ACS11 and ACO5 genes and thus promoted basal ethylene production. WRKY29 protein was localized in nuclei and was a transcriptional activator. Overexpression of WRKY29 caused pleiotropic effect on plant growth, development and showed obvious response even without ACC treatment. Inducible overexpression of WRKY29 also reduced primary root elongation and lateral root growth. A triple response assay of overexpression and mutant seedlings of WRKY29 showed that overexpression seedlings had shorter hypocotyls than the transgenic GFP (Green Fluorescence Protein) control, while mutants had no difference from wild-type. A qRT-PCR assay demonstrated that expression of multiple ACSs and ACO5 was up-regulated in WRKY29 overexpression plants. A transactivation assay through dual luciferase reporter system confirmed the regulation of promoters of ACS5, ACS6, ACS8, ACS11 and ACO5 by WRKY29. Both in vivo chromatin immunoprecipitation (ChIP)- quantitative PCR and in vitro electrophoretic mobility shift assay (EMSA) revealed that WRKY29 directly bound to the promoter regions of its target genes. Taken together, these results suggest that WRKY29 is a novel TF positively regulating ethylene production by modulating the expression of ACS and ACO genes.

Study on the Thermohydrodynamic Friction Characteristics of Surface-Textured Valve Plate of Axial Piston Pumps.

The purpose of this paper is to study the oil film and friction characteristics of valve plates with a micro-textured surface and to explore the influence of textures of different shapes and sizes on the valve plates. Firstly, on the basis of thermohydrodynamic theory, this paper established the lubrication model of the oil film on the valve plate pair of swashplate axial piston pumps, according to the Reynolds equation. Secondly, the micro-texture was added to the mathematical model of the valve plate pair's oil film. A combination of the energy equation, oil-film-thickness equation, elastic deformation equation, viscosity-pressure and viscosity-temperature equation, the finite difference method, as well as the relaxation iteration method, was used to solve the problem, and the textured and non-textured valve plate surfaces were simulated. The nephogram of the oil-film-thickness distribution, elastic deformation distribution, oil-film-pressure distribution and oil-film-temperature distribution were generated. Then, the control variable method was used to change the cylinder rotational speed, tilt angle, oil viscosity, initial oil film thickness and other parameters to analyze their effects on oil film characteristics. In addition, the friction characteristics of non-textured surfaces, square textured surfaces, triangular textured surfaces and circular textured surfaces were compared and analyzed. It was found that the textured surface of valve plates can obviously improve friction efficiency under the same operating conditions. The square texture, especially, is the preferable shape, rather than the triangular texture and the circular texture, and the friction performance is at its best when the texture depths are between 20 µm and 50 µm. The results provide a theoretical basis for the design and improvement of the valve plate.

Valerian essential oil for treating insomnia via the serotonergic synapse pathway.

Valerian volatile oil can be used in the treatment of insomnia; however, the active components and mechanisms of action are currently unclear. Therefore, we used transcriptome sequencing and weight coefficient network pharmacology to predict the effective components and mechanism of action of valerian volatile oil in an insomnia model induced by intraperitoneal injection of para-Chlorophenylalanine (PCPA) in SD rats. Valerian essential oil was given orally for treatment and the contents of 5-hydroxytryptamine receptor 1 A (5-HT1AR), γ-aminobutyric acid (GABA), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA) in the hippocampus of rats in each group were detected by enzyme-linked immunosorbent assay (ELISA), western blot, Polymerase Chain Reaction (PCR), and immunohistochemistry. The results showed that after treatment with valerian essential oil, insomnia rats showed significantly prolonged sleep duration and alleviated insomnia-induced tension and anxiety. Regarding the mechanism of action, we believe that caryophyllene in valerian essential oil upregulates the 5-HT1AR receptor to improve the activity or affinity of the central transmitter 5-HT, increase the release of 5-HT, couple 5-HT with a G protein coupled receptor, convert adenosine triphosphate (ATP) into cAMP (catalyzed by ADCY5), and then directly regulate the downstream pathway. Following pathway activation, we propose that the core gene protein kinase PKA activates the serotonergic synapse signal pathway to increase the expression of 5-HT and GABA, thus improving insomnia symptoms and alleviating anxiety. This study provides a theoretical basis for the application of valerian volatile oil in health food.

Computational simulations of the 4D micro-circulatory network in zebrafish tail amputation and regeneration.

Wall shear stress (WSS) contributes to the mechanotransduction underlying microvascular development and regeneration. Using computational fluid dynamics, we elucidated the interplay between WSS and vascular remodelling in a zebrafish model of tail amputation and regeneration. The transgenic Tg (fli1:eGFP; Gata1:ds-red) zebrafish line was used to track the three-dimensional fluorescently labelled vascular endothelium for post-image segmentation and reconstruction of the fluid domain. Particle image velocimetry was used to validate the blood flow. Following amputation to the dorsal aorta and posterior cardinal vein (PCV), vasoconstriction developed in the dorsal longitudinal anastomotic vessel (DLAV) along with increased WSS in the proximal segmental vessels (SVs) from amputation. Angiogenesis ensued at the tips of the amputated DLAV and PCV where WSS was minimal. At 2 days post amputation (dpa), vasodilation occurred in a pair of SVs proximal to amputation, followed by increased blood flow and WSS; however, in the SVs distal to amputation, WSS normalized to the baseline. At 3 dpa, the blood flow increased in the arterial SV proximal to amputation and through anastomosis with DLAV formed a loop with PCV. Thus, our in silico modelling revealed the interplay between WSS and microvascular adaptation to changes in WSS and blood flow to restore microcirculation following tail amputation.

Tunable image projection spectrometry.

We present tunable image projection spectrometry (TIPS), a Fourier-domain line-scan spectral imager with a tunable compression ratio. Compared to state-of-the-art spatial-domain pushbroom hyperspectral cameras, TIPS requires much fewer measurements and provides a higher light throughput. Using a rotating Dove prism and a cylindrical field lens, TIPS scans an input scene in the Fourier domain and captures a subset of multi-angled one-dimensional (1D) en face projections of the input scene, allowing a tailored data compression ratio for a given scene. We demonstrate the spectral imaging capability of TIPS with a hematoxylin and eosin (H&E) stained pathology slide. Moreover, we showed the spectral information obtained can be further converted to depths when combining TIPS with a low-coherence full-field spectral-domain interferometer.

A hybrid of light-field and light-sheet imaging to study myocardial function and intracardiac blood flow during zebrafish development.

Biomechanical forces intimately contribute to cardiac morphogenesis. However, volumetric imaging to investigate the cardiac mechanics with high temporal and spatial resolution remains an imaging challenge. We hereby integrated light-field microscopy (LFM) with light-sheet fluorescence microscopy (LSFM), coupled with a retrospective gating method, to simultaneously access myocardial contraction and intracardiac blood flow at 200 volumes per second. While LSFM allows for the reconstruction of the myocardial function, LFM enables instantaneous acquisition of the intracardiac blood cells traversing across the valves. We further adopted deformable image registration to quantify the ventricular wall displacement and particle tracking velocimetry to monitor intracardiac blood flow. The integration of LFM and LSFM enabled the time-dependent tracking of the individual blood cells and the differential rates of segmental wall displacement during a cardiac cycle. Taken together, we demonstrated a hybrid system, coupled with our image analysis pipeline, to simultaneously capture the myocardial wall motion with intracardiac blood flow during cardiac development.

Membrane-Bound Transcriptional Activator NTL1 from Rapeseed Positively Modulates Leaf Senescence through Targeting Genes Involved in Reactive Oxygen Species Production and Programmed Cell Death.

Leaf senescence is the last stage of leaf development and is determined by various environmental and endogenous signals. Leaf senescence can determine plant productivity and fitness. Transcription factors (TFs) with the transmembrane domain constitute a special group of regulatory proteins that can translocate from the membrane system into nuclei to exert the transcriptional function upon endogenous or exogenous stimuli. Reactive oxygen species (ROSs) play an important role in numerous processes throughout the life cycle of plants including leaf senescence. Leaf senescence is characterized by massive programmed cell death (PCD) and is a type of developmental PCD. The transcriptional regulatory relationships between membrane-bound TFs and leaf senescence remain largely uncharacterized, especially in rapeseed (Brassica napus L.), an important oil crop. Here, we show that BnaNTL1 is a membrane-bound NAC (NAM, ATAF, and CUC) TF, which is predominantly expressed in senescent leaves. Expression of BnaNTL1ΔTM, a form of BnaNTL1 devoid of the transmembrane domain, can induce serious HR-like cell death symptoms and ROS accumulation in cells. Plants overexpressing BnaNTL1ΔTM show earlier leaf senescence compared with the control, accompanied by chlorophyll degradation and electrolyte leakage. Genes involved in ROS production (RbohD), PCD (VPEs and CEP1), and leaf senescence (BFN1) are significantly induced and activated by BnaNTL1ΔTM according to the quantitative reverse transcription PCR (qRT-PCR) analysis and dual luciferase reporter (Dual-LUC) assay. Moreover, electrophoretic mobility shift assay revealed that BnaNTL1 directly bound to the NTLBS elements in promoters of RbohD, γVPE, and BFN1. In conclusion, these results demonstrate that BnaNTL1 positively modulates ROS production and HR-like cell death to induce leaf senescence.

Real-time volumetric reconstruction of biological dynamics with light-field microscopy and deep learning.

Light-field microscopy has emerged as a technique of choice for high-speed volumetric imaging of fast biological processes. However, artifacts, nonuniform resolution and a slow reconstruction speed have limited its full capabilities for in toto extraction of dynamic spatiotemporal patterns in samples. Here, we combined a view-channel-depth (VCD) neural network with light-field microscopy to mitigate these limitations, yielding artifact-free three-dimensional image sequences with uniform spatial resolution and high-video-rate reconstruction throughput. We imaged neuronal activities across moving Caenorhabditis elegans and blood flow in a beating zebrafish heart at single-cell resolution with volumetric imaging rates up to 200 Hz.

Saak Transform-Based Machine Learning for Light-Sheet Imaging of Cardiac Trabeculation.

OBJECTIVE: Recent advances in light-sheet fluorescence microscopy (LSFM) enable 3-dimensional (3-D) imaging of cardiac architecture and mechanics in toto. However, segmentation of the cardiac trabecular network to quantify cardiac injury remains a challenge. METHODS: We hereby employed "subspace approximation with augmented kernels (Saak) transform" for accurate and efficient quantification of the light-sheet image stacks following chemotherapy-treatment. We established a machine learning framework with augmented kernels based on the Karhunen-Loeve Transform (KLT) to preserve linearity and reversibility of rectification. RESULTS: The Saak transform-based machine learning enhances computational efficiency and obviates iterative optimization of cost function needed for neural networks, minimizing the number of training datasets for segmentation in our scenario. The integration of forward and inverse Saak transforms can also serve as a light-weight module to filter adversarial perturbations and reconstruct estimated images, salvaging robustness of existing classification methods. The accuracy and robustness of the Saak transform are evident following the tests of dice similarity coefficients and various adversary perturbation algorithms, respectively. The addition of edge detection further allows for quantifying the surface area to volume ratio (SVR) of the myocardium in response to chemotherapy-induced cardiac remodeling. CONCLUSION: The combination of Saak transform, random forest, and edge detection augments segmentation efficiency by 20-fold as compared to manual processing. SIGNIFICANCE: This new methodology establishes a robust framework for post light-sheet imaging processing, and creating a data-driven machine learning for automated quantification of cardiac ultra-structure.

[Investigation of Paeonia sinjiangensis resources using remote sensing and expert knowledge].

OBJECTIVE: To study the effectiveness and feasibility of remote sensing technology in the rare species of wild plant resources. METHOD: The mechanism and characteristics of Paeonia sinjiangensis were analyzed to find the possibility of extracting from TM imagery. An expert system has been used with Landsat Thematic Mapper data to derive P. sinjiangensis. Then logical decision rules were used with the various datasets to assign values. RESULT: The land for P. sinjiangensis possible growth were mapped and accuracy tested was approving. CONCLUSION: The results suggest that the remote sensing expert interpretation system using satellite imagery and ancillary data will be feasible for research of rare wild medicinal plants distribution.

Overexpression of a putative maize calcineurin B-like protein in Arabidopsis confers salt tolerance.

The calcineurin B-like proteins (CBLs) represent a unique family of calcium sensors in plants. Although extensive studies and remarkable progress have been made in Arabidopsis (Arabidopsis thaliana) CBLs, their functions in other plant species are still quite limited. Here, we report the cloning and functional characterization of ZmCBL4, a novel CBL gene from maize (Zea mays). ZmCBL4 encodes a putative homolog of the Arabidopsis CBL4/SOS3 protein, with novel properties. ZmCBL4 has one copy in maize genome and harbors seven introns in its coding region. ZmCBL4 expressed differentially in various organs of the maize plants at a low level under normal condition, and its expression was regulated by NaCl, LiCl, ABA and PEG treatments. Expression of 35S::ZmCBL4 not only complemented the salt hypersensitivity in Arabidopsis sos3 mutant, but also enhanced the salt tolerance in Arabidopsis wild type at the germination and seedling stages. Moreover, the LiCl tolerance in all of the ZmCBL4-expressing lines increased more significantly as compared with the NaCl tolerance, and in consistent with this, it was found that the expression of Arabidopsis AtNHX8, a putative plasma membrane Li+/H+ antiporter gene identified recently, was induced in these transgenic lines under LiCl stress. The ZmCBL4-expressing Arabidopsis lines accumulated less Na+ and Li+ as compared with the control plants. This study has identified a putative maize CBL gene which functions in the salt stress-elicited calcium signaling and thus in the tolerance to salinity.

[Study on mechanism of the circulation reconstructing of skin flap after early-repeated short ischemia training].

OBJECTIVE: To investigate the effects of repeated short ischemia training on flap survival area, vascular endothelial growth factor and the microvascularsel density. METHODS: Seventy-two rabbits were divided into: the experimental group (n=64), the skin flaps were constructed in two sides of back, one side flap were given ischemia training for 15 minutes and 8 times one day at the pedicles from the 1st to 8th day after operation (group A), the other side flap was served as a control (group B), the corresponding site was only marked as a blank control group (group C). Then, 8 pedicles of group A and group B were isolated every day. The surviving area of all skin flaps were calculated on the 5th day after isolating operation. The vascular endothelial growth factor (VEGF) and microvessel density(MVD) of the 3 groups were checked with immunohistologochemical staining. RESULTS: After the operation, all animals were survival with normal vitality. The survival flap area of group A were significant more than that of group B after 3 days (P<0.05). The expressions of VEGF and MVD of group A and group B were higher than group C. The expression of VEGF of group A was significantly higher than that of group B (P<0.01). The counting of MVD of group A was also significantly higher than that of group B (P<0.05). There was positive correlation between flap survival area and MVD in group A. The relation of time point was n and n-2 respectively,correlation coefficient was 0.850. As well as MVD and VEGF were positive correlation, correlation coefficient was 0.801. CONCLUSION: Early repeated short ischemia training can increase flap survival area, the mechanism maybe involve the increased expression of VEGF, which can increased skin flap microvascular density.