Triple-path feature transform network for ring-array photoacoustic tomography image reconstruction

Photoacoustic imaging(PAI)is a noninvasive emerging imaging method based on the photoacoustic effect,which provides necessary assistance for medical diagnosis.It has the characteristics of large imaging depth and high contrast.However,limited by the equipment cost and reconstruction time requirements,the existing PAI systems distributed with annular array transducers are difficult to take into account both the image quality and the imaging speed.In this paper,a triple-path feature transform network(TFT-Net)for ring-array photoacoustic tomography is proposed to enhance the imaging quality from limited-view and sparse measurement data.Specifically,the network combines the raw photoacoustic pressure signals and conventional linear reconstruction images as input data,and takes the photoacoustic physical model as a prior information to guide the reconstruction process.In addition,to enhance the ability of extracting signal features,the residual block and squeeze and excitation block are introduced into the TFT-Net.For further efficient reconstruction,the final output of photoacoustic signals uses‘filter-then-upsample’operation with a pixel-shuffle multiplexer and a max out module.Experiment results on simulated and in-vivo data demonstrate that the constructed TFT-Net can restore the target boundary clearly,reduce background noise,and realize fast and high-quality photoacoustic image reconstruction of limited view with sparse sampling.

The role of stereotactic body radiotherapy in hepatocellular carcinoma:guidelines and evidences

Hepatocellular carcinoma(HCC)is a common malignancy with high mortality rates.While surgery can be curative in early-stage disease,80% of patients cannot undergo surgical resection.Stereotactic body radiotherapy(SBRT),an emerging,non-invasive,precision treatment,has shown promising results across various stages of HCC and has thus been adopted in practice to varying degrees around the world.This article aims to review current guideline recommendations on SBRT,clinical evidence,and outcome comparisons with other local treatment modalities.Attempts are also made to compare the differences in clinical trials between Asian and Western countries.

Plant multiscale networks:charting plant connectivity by multi-level analysis and imaging techniques

In multicellular and even single-celled organisms,individual components are interconnected at multiscale levels to produce enormously complex biological networks that help these systems maintain homeostasis for development and environmental adaptation.Systems biology studies initially adopted network analysis to explore how relationships between individual components give rise to complex biological processes.Network analysis has been applied to dissect the complex connectivity of mammalian brains across different scales in time and space in The Human Brain Project.In plant science,network analysis has similarly been applied to study the connectivity of plant components at the molecular,subcellular,cellular,organic,and organism levels.Analysis of these multiscale networks contributes to our understanding of how genotype determines phenotype.In this review,we summarized the theoretical framework of plant multiscale networks and introduced studies investigating plant networks by various experimental and computational modalities.We next discussed the currently available analytic methodologies and multi-level imaging techniques used to map multiscale networks in plants.Finally,we highlighted some of the technical challenges and key questions remaining to be addressed in this emerging field.

Three-dimensional reconstruction of Picea wilsonii Mast. pollen grains using automated electron microscopy

Three-dimensional electron microscopy(3 D-EM) has attracted considerable attention because of its ability to provide detailed information with respect to developmental analysis. However, large-scale high-resolution 3 D reconstruction of biological samples remains challenging. Herein, we present a 3 D view of a Picea wilsonii Mast. pollen grain with 100 nm axial and38.57 nm lateral resolution using AutoCUTS-SEM(automatic collector of ultrathin sections-scanning electron microscopy). We established a library of 3,127 100 nm thick serial sections of pollen grains for preservation and observation, demonstrating that the protocol can be used to analyze large-volume samples. After obtaining the SEM images, we reconstructed an entire pollen grain comprising 734 serial sections. The images produced by 3D reconstruction clearly revealed the main components of the P.wilsonii pollen grain, i.e., two sacci and pollen corpus, tube cell, generative cell, and two degenerated prothallial cells, and their internal organization. In addition, we performed a quantitative analysis of the different pollen grain cells, including sacci, and found that there were 202 connections within a saccus SEM image. Thus, for the first time, this study provided a global 3D view of the entire pollen grain, which will be useful for analyzing pollen development and growth.

Quantitative analysis of microplastics in coastal tidal-flat reclamation in Dongtai,China

Coastal tidal flats have received considerable attention in recent years,as they provide a direct channel for the discharge of terrestrial microplastics into the ocean.Land reclamation is occurring increasingly frequently in coastal tidal-flats;however,the environmental impacts of these activities remain unclear.Therefore,this pioneering study assessed the microplastic emission characteristics of reclamation geotextiles and performed a risk assessment accordingly.Morphological characterization of geotextile samples collected from five sites in Dongtai,China,provided evidence of sedimentary weathering.Based on several assumptions,the average abundance of microplastics in soil covered by geotextiles was estimated to reach 349137 particles/kg dry weight,with the total microplastic load in the reclaimed area estimated to be 20.678.06 t.Compared with previous studies,this research demonstrates that coastal reclamation areas store a high concentration of microplastics,aggravating marine microplastic pollution.Moreover,conditional fragmentation model results revealed that the weathering and distribution characteristics of soil microplastics in coastal tidal-flat areas exhibit spatial heterogeneity,being more easily affected by natural factors(such as tides)than those in inland areas.As a result of tides,the annual discharge of geotextile-originating microplastics from the studied areas into the ocean was approximately 2465.52960.77 t.These findings prove that the risks posed by engineering-microplastics are significant,indicating that further investigations are required on the precise laws of transfer and migration,as well as the toxicity mechanisms,in order to improve analytical techniques and policies in this field.

IGF2BP3 Enhances the Growth of Hepatocellular Carcinoma Tumors by Regulating the Properties of Macrophages and CD8^(+)T Cells in the Tumor Microenvironment

Background and Aims:Overexpression of IGF2BP3 is associated with the prognosis of hepatocellular carcinoma(HCC).However,its role in regulating tumor immune microenvironment(TME)is not well characterized.Here,we investigated the effects of IGF2BP3 on macrophages and CD8^(+)T cells within the TME of HCC.Methods:The relationship between IGF2BP3 and immune cell infiltration was analyzed using online bioinformatics tools.Knockout of IGF2BP3 in mouse hepatoma cell line Hepa1-6 was established using CRISPR/Cas9 technology.In vitro cell coculture and subcutaneously implanted hepatoma mice model were used to explore the effects of IGF2BP3 on immune cells.Expression of CCL50l transforming growth factor beta 1(TGF-β1)was detected with quantitative real-time polymerase chain reaction,western blotting,and enzyme-linked immunosorbent assay.The binding of IGF2BP3 and its target RNA was verified by trimolecular fluorescence complementation system and RNA immunoprecipitation followed by quantitative or semiquantitative polymerase chain reaction.Results:IGF2BP3 expression was elevated in HCC and was positively correlated with macrophage infiltration.Patients with higher IGF2BP3 expression and lower macrophage infiltration had a better survival rate.We found that IGF2BP3 could bind to the mRNA of CCL5 or TGF-β1,increasing their expression,and inducing macrophage infiltration and M2 polarization while inhibiting the activation of CD8^(+)T cells.Furthermore,inhibition of IGF2BP3 combined with anti-CD47 antibody treatment significantly suppressed the growth of hepatoma in Hepa1-6 xenograft tu-mor mice.Conclusions:IGF2BP3 promoted the infiltration and M2-polarization of macrophages and suppressed CD8^(+)T activation by enhancing CCL5 and TGF-β1 expression,which facilitated the progression of Hepa1-6 xenograft tumor.

Targeting carnitine palmitoyl transferase 1A(CPT1A)induces ferroptosis and synergizes with immunotherapy in lung cancer

Despite the successful application of immune checkpoint therapy,no response or recurrence is typical in lung cancer.Cancer stem cells(CSCs)have been identified as a crucial player in immunotherapy-related resistance.Ferroptosis,a form of cell death driven by iron-dependent lipid peroxidation,is highly regulated by cellular metabolism remolding and has been shown to have synergistic effects when combined with immunotherapy.Metabolic adaption of CsCs drives tumor resistance,yet the mechanisms of their ferroptosis defense in tumor immune evasion remain elusive.Here,through metabolomics,transcriptomics,a lung epithelialspecific Cptla-knockout mouse model,and clinical analysis,we demonstrate that CPT1A,a key rate-limiting enzyme of fatty acid oxidation,acts with L-carnitine,derived from tumor-associated macrophages to drive ferroptosis-resistance and CD8^(+)T cells inactivation in lung cancer.Mechanistically,CPT1A restrains ubiquitination and degradation of c-Myc,while c-Myc transcriptionally activates CPT1A expression.The CPT1A/c-Myc positive feedback loop further enhances the cellular antioxidant capacity by activating the NRF2/GPX4 system and reduces the amount of phospholipid polyunsaturated fatty acids through ACSL4 downregulating,thereby suppressing ferroptosis in CSCs.Significantly,targeting CPT1A enhances immune checkpoint blockadeinduced anti-tumor immunity and tumoral ferroptosis in tumor-bearing mice.The results illustrate the potential of a mechanismguided therapeutic strategy by targeting a metabolic vulnerability in the ferroptosis of CsCs to improve the efficacy of lung cancer immunotherapy.

光学透明技术在植物多尺度成像中的应用

光学透明技术是一种通过各种化学试剂,将原本不透明的生物样本实现透明化,并在光学显微镜下深度成像的技术。结合多种光学显微成像新技术,光学透明技术可对整个组织进行成像和三维重建,深度剖析生物体内部空间特征与形成机制。近年来,多种植物光学透明技术和多尺度成像技术被陆续研发,并取得了丰硕的研究成果。该文综述了生物体光学透明技术的基本原理和一些新技术,重点介绍基于光学透明技术开发的新型成像方法及其在植物成像与细胞生物学中的应用,为后续植物整体、组织或器官的透明、成像与三维重构及功能研究提供理论依据和技术支持。

A Distributed Reactive Power Sharing Approach in Microgrids with Improved Droop Control

Conventional droop control causes frequency and voltage deviations(from rated value)in a inverter-intensive microgrid(MG),and the reactive power sharing cannot be obtained when the communication structure of the MG or load suddenly changes.Compared with a centralized control and droop control scheme,a distributed hierarchical control structure of the MG can overcome the limitation of communication and realize reactive power sharing.In this paper,an improved droop control is adopted,which is based on the hierarchical control structure.The hierarchical control structure consists of zerolevel control,primary control and a proposed secondary control.First,the secondary controller is modeled,and the MG system composed of distributed generators(DGs)is considered as a multi-agent system.The secondary controller can make up for the shortcomings of the droop controller and adjust the frequency and voltage to their rated values.Secondly,the reference voltage and frequency of the zero-level control are calculated,and combined with the primary control.The zero-level control and primary control can make the voltage and frequency of the MG run stably and provide reference voltage for the inverter.Finally,the stability of the system is proved by the theory of multi-agent consistency.A simulation system is established in the Matlab/Simulink environment,and the results show the effectiveness of the proposed controller.

A Finite-time Distributed Cooperative Control Approach for Microgrids

Reactive power sharing cannot be achieved using many existing microgrid(MG)control methods,but the convergence speed of these methods is slow.To solve these problems,a finite-time distributed control approach is proposed in this paper,which is based on the hierarchical control structure.The hierarchical control structure consists of a dual loop control,a droop control used as a primary control and a secondary control.First,the secondary controller is modeled,and the MG system composed of distributed generators(DGs)is considered as a multi-agent system.The secondary controller consists of a frequency regulator,voltage regulator and power regulator.Secondly,the adaptive virtual impedance module is established,using the output of the reactive power regulator as its input.Thirdly,a dual loop controller is combined with a primary controller and secondary controller to generate a pulse width modulation(PWM)signal to control the power and voltage of the MG.In order to reduce the fluctuation of the MG,a damping module is introduced when the structure of the system changes.Finally,the stability of the proposed control strategy is proved by the related theorems.A simulation system is established in the Matlab environment,and the simulation results show that the proposed method is effective.