Dynamic Structural Changes Research Articles

Using in vivo intact structure for system-wide quantitative analysis of changes in proteins

Mass spectrometry-based methods can provide a global expression profile and structural readout of proteins in complex systems. Preserving the in vivo conformation of proteins in their innate state is challenging during proteomic experiments. Here, we introduce a whole animal in vivo protein footprinting method using perfusion of reagents to add dimethyl labels to exposed lysine residues on intact proteins which provides information about protein conformation. When this approach is used to measure dynamic structural changes during Alzheimer’s disease (AD) progression in a mouse model, we detect 433 proteins that undergo structural changes attributed to AD, independent of aging, across 7 tissues. We identify structural changes of co-expressed proteins and link the communities of these proteins to their biological functions. Our findings show that structural alterations of proteins precede changes in expression, thereby demonstrating the value of in vivo protein conformation measurement. Our method represents a strategy for untangling mechanisms of proteostasis dysfunction caused by protein misfolding. In vivo whole-animal footprinting should have broad applicability for discovering conformational changes in systemic diseases and for the design of therapeutic interventions.

Dynamic Nanostructure-Based DNA Logic Gates for Cancer Diagnosis and Therapy.

DNA logic gates with dynamic nanostructures have made a profound impact on cancer diagnosis and treatment. Through programming the dynamic structure changes of DNA nanodevices, precise molecular recognition with signal amplification and smart therapeutic strategies have been reported. This enhances the specificity and sensitivity of cancer theranostics, and improves diagnosis precision and treatment outcomes. This review explores the basic components of dynamic DNA nanostructures and corresponding DNA logic gates, as well as their applications for cancer diagnosis and therapies. The dynamic DNA nanostructures would contribute to cancer early detection and personalized treatment.

A guide to studying 3D genome structure and dynamics in the kidney.

The human genome is tightly packed into the 3D environment of the cell nucleus. Rapidly evolving and sophisticated methods of mapping 3D genome architecture have shed light on fundamental principles of genome organization and gene regulation. The genome is physically organized on different scales, from individual genes to entire chromosomes. Nuclear landmarks such as the nuclear envelope and nucleoli have important roles in compartmentalizing the genome within the nucleus. Genome activity (for example, gene transcription) is also functionally partitioned within this 3D organization. Rather than being static, the 3D organization of the genome is tightly regulated over various time scales. These dynamic changes in genome structure over time represent the fourth dimension of the genome. Innovative methods have been used to map the dynamic regulation of genome structure during important cellular processes including organism development, responses to stimuli, cell division and senescence. Furthermore, disruptions to the 4D genome have been linked to various diseases, including of the kidney. As tools and approaches to studying the 4D genome become more readily available, future studies that apply these methods to study kidney biology will provide insights into kidney function in health and disease.

Voltage-clamp fluorometry for advancing mechanistic understanding of ion channel mechanisms with a focus on acid-sensing ion channels.

Voltage-clamp fluorometry (VCF) has revolutionized the study of ion channels by combining electrophysiology with fluorescence spectroscopy. VCF allows ion channel researchers to link dynamic structural changes, measured in real time, to function. Acid-sensing ion channels (ASICs) are Na+-permeable non-voltage-gated ion channels of the central and peripheral nervous system. They function as pH sensors, triggering neuronal excitation when pH decreases. Animal studies have shown the importance of ASICs for pain and fear sensation, learning, and neurodegeneration following ischaemic stroke. This review explores the technical bases and various developments of VCF, including fluorescence resonance energy transfer and the use of unnatural fluorescent amino acids. We provide an overview of VCF applications with a focus on ASICs, detailing how VCF has unveiled proton-induced conformational changes in key regions such as the acid pocket, wrist, and pore, crucial for understanding transitions between closed, open, and desensitized states.

Differentiating Reactive Oxygen Species with DNA Framework Monitors.

The lifespan, oxidizing properties, bonding behaviors, and reactivity of reactive oxygen species (ROS) produced during photocatalytic activation can vary significantly due to the differences in electron configurations of ROS, which are dependent on their generation mechanisms: energy transfer or charge transfer. Hence, identifying and differentiating ROS of different mechanisms can improve our understanding of redox reactions and related diseases, providing a basis for the prevention and treatment of related diseases. Here, we have developed a DNA framework monitor (DFM) based on dynamic DNA structural changes to effectively distinguish the two types of ROS produced in photocatalytic activation of O2. This DFM provides a visualization tool for observing the reaction kinetics of ROS with DNA, not only distinguishing two types of ROS with different mechanisms but also serving as a universal system for evaluating the efficacy and performance of nanomaterials for ROS regulation.

Effects of Dynamic Surface Transformation on the Activity and Stability of Mixed Co‐Mn Cubic Spinel Oxides in the Oxygen Evolution Reaction in Alkaline Media

AbstractAn atomic‐scale understanding of how electrocatalyst surfaces reconstruct and transform during electrocatalytic reactions is essential for optimizing their activity and longevity. This is particularly important for the oxygen evolution reaction (OER), where dynamic and substantial structural and compositional changes occur during the reaction. Herein, a multimodal method is developed by combining X‐ray fine structure absorption and photoemission spectroscopy, transmission electron microscopy, and atom probe tomography with electrochemical measurements to interrogate the temporal evolution of oxidation states, atom coordination, structure, and composition on Co2MnO4 and CoMn2O4 cubic spinel nanoparticle surfaces upon OER cycling in alkaline media. Co2MnO4 is activated at the onset of OER due to the formation of ≈2 nm Co‐Mn oxyhydroxides with an optimal Co/Mn ratio of ≈3. As OER proceeds, Mn dissolution and redeposition occur for the CoMn oxyhydroxides, extending the OER stability of Co2MnO4. Such dynamic dissolution and redeposition are also observed for CoMn2O4, leading to the formation of less OER‐active Mn‐rich oxides on the nanoparticle surfaces. This study provides mechanistic insights into how dynamic surface reconstruction and transformation affect the activity and stability of mixed CoMn cubic spinels toward OER.

Stronger Impact of Extreme Heat Event on Vegetation Temperature Sensitivity under Future Scenarios with High-Emission Intensity

Vegetation temperature sensitivity is a key indicator to understand the response of vegetation to temperature changes and predict potential shifts in ecosystem functions. However, under the context of global warming, the impact of future extreme heat events on vegetation temperature sensitivity remains poorly understood. Such research is crucial for predicting the dynamic changes in terrestrial ecosystem structure and function. To address this issue, we utilized historical (1850–2014) and future (2015–2100) simulation data derived from CMIP6 models to explore the spatiotemporal dynamics of vegetation temperature sensitivity under different carbon emission scenarios. Moreover, we employed correlation analysis to assess the impact of extreme heat events on vegetation temperature sensitivity. The results indicate that vegetation temperature sensitivity exhibited a declining trend in the historical period but yielded an increasing trend under the SSP245 and SSP585 scenarios. The increasing trend under the SSP245 scenario was less pronounced than that under the SSP585 scenario. By contrast, vegetation temperature sensitivity exhibited an upward trend until 2080 and it began to decline after 2080 under the SSP126 scenario. For all the three future scenarios, the regions with high vegetation temperature sensitivity were predominantly located in high latitudes of the Northern Hemisphere, the Tibetan Plateau, and tropical forests. In addition, the impact of extreme heat events on vegetation temperature sensitivity was intensified with increasing carbon emission intensity, particularly in the boreal forests and Siberian permafrost. These findings provide important insights and offer a theoretical basis and guidance to identify climatically sensitive areas under global climate change.

Summer daily dynamics of the vertical structure of atmospheric aerosol over Baikal coastal area from ground-based lidar measurements

ABSTRACT The spatial structure of atmospheric aerosol over Baikal in summer is studied on a regular basis with the use of ground-based LOSA-M2 lidar measurements at the Boyarsky scientific station of the Institute of Physical Material Science, Siberian Branch, Russian Academy of Sciences (51.83°N, 106.06°E, 456 m a.s.l.), Republic of Buryatia, Russia. The lake is located in a basin surrounded by mountain ranges on all side; its water volume is large. The lidar data are analysed along with the regional meteorological situation and meteorological parameters of the atmosphere. The daily dynamics of aerosol distribution over the atmospheric is examined for the period from 2015 to 2023 accounting the effect of different air masses in the region. Three main typical air circulation types are identified for the coastal zone of southern Baikal in summer, which determine the atmospheric aerosol generation and transport. The first and most common type relates to breeze circulation, where the main changes in the spatial structure of aerosol occur in the 2–3-km layer and are determined by changes in the transport direction within a breeze cell during the day. The main feature of this type is a decrease in the altitude of an air layer which contains most of aerosol in the lower atmosphere up to 1 km. The second type refers to southwestern transport under the presence of an anticyclone over the region. The maximal altitude of the aerosol layers attains 7 km in this case. The most complex and dynamic changes in the daily spatial structure of atmospheric aerosol occurred under transport of cyclones and associated atmospheric fronts over Lake Baikal. Under this third type, the altitude of the aerosol layers decreases throughout the day within the altitude range from the surface to 3–4 km.

Flow topology and mixing in alveolar edema: Unsteady flow in interconnected cavities with moving walls

The study of alveolar fluid mechanics is critical for comprehending respiratory function and lung diseases, particularly in cases of alveolar lesions that result in significant structural and fluid dynamic changes. This study investigates the flow topology and chaotic mixing within both normal and edematous alveoli, where the alveoli in the edematous model are interconnected by pores. To numerically simulate alveolar flow, a mathematical model is developed to ascertain the key parameters of Reynolds number (Re) and alveolar expansion ratio. Subsequently, the flow fields are analyzed to determine wall shear stress (WSS) and to identify WSS critical points and critical points of velocity vector, with a thorough presentation of the various flow topologies corresponding to these critical points. Moreover, a dynamic mode decomposition-based method is introduced to track particle trajectories, and the exploration of chaotic mixing is conducted through tracer advection, Poincare map, and the calculation of finite-time Lyapunov exponents. Results indicate that the edematous model exhibits a higher Re and higher WSS due to the fluid properties. Within the alveoli, high WSS is usually localized at the pores. The pores increase critical points and alter flow topologies, significantly changing chaotic mixing. Additionally, Re and alveolar locations also affect mixing patterns. These findings are crucial for understanding alveolar physiology and designing inhaled drugs for lung diseases, considering the role of chaos in particle transport in the lung acini.

Neurotransmitter recognition by human vesicular monoamine transporter 2

Human vesicular monoamine transporter 2 (VMAT2), a member of the SLC18 family, plays a crucial role in regulating neurotransmitters in the brain by facilitating their uptake and storage within vesicles, preparing them for exocytotic release. Because of its central role in neurotransmitter signalling and neuroprotection, VMAT2 is a target for neurodegenerative diseases and movement disorders, with its inhibitor being used as therapeutics. Despite the importance of VMAT2 in pharmacophysiology, the molecular basis of VMAT2-mediated neurotransmitter transport and its inhibition remains unclear. Here we show the cryo-electron microscopy structure of VMAT2 in the substrate-free state, in complex with the neurotransmitter dopamine, and in complex with the inhibitor tetrabenazine. In addition to these structural determinations, monoamine uptake assays, mutational studies, and pKa value predictions were performed to characterize the dynamic changes in VMAT2 structure. These results provide a structural basis for understanding VMAT2-mediated vesicular transport of neurotransmitters and a platform for modulation of current inhibitor design.

Dynamic changes in the chemical structure and gelling properties of pectin at different stages of citrus maturation and storage

Citrus pectins (CP) are the most common types of commercial pectins, and their gelling properties are of interest in many industrial applications. However, the dynamic changes in the chemical structures and gelling properties of pectins during citrus maturation and storage are poorly understood. This study compared pectins from citrus fruit in terms of different maturity (M1: green citrus; M2: green-yellow citrus; M3: light orange citrus; FM: full maturity citrus) and storage times (S1: 10-day; S2: 20-day; S3: 30-day). All pectin were high-methoxylated polymers, with high content of HG and RG-I domain (about 95.0 mol%). With increasing citrus maturity and storage time, HG content (from 69.0 mol% to 51.9 mol%), the molecular weight and methyl-esterification of pectins continuously decreased, while the RG-I content (from 26.4 mol% to 42.5 mol%) and compact spatial conformation significantly increased. Polygalacturonase, methylesterase, α-arabinofuranosidase, β-galactosidase, and cellulase, induced dynamic variations in the structural characteristics of pectins. The decreases in HG content and the lower molecular weight reduced hydrogen bonding and the hydrophobic interactions, thus weakening the gelling properties. The relatively high RG-I content, the additional hydrogen bonds generated by the free carboxyl groups, and the compact conformation shortened the distances between pectin chains and increased chain entanglement, thereby ensuring that the gel network was stable. Consequently, CPS3 gel exhibited the greatest strength (hardness: 977.0 g, Aα: 642.9 Pa sα) and satisfactory extrusion recovery ability (springiness: 95.5%). These results can guide the selection of raw materials that will yield pectins with specific structural characteristics and superior gelling properties.

Multi-objective optimization of forest structure for broadleaf mixed forest under different CMIP5 scenarios

Climate change is an important global research topic and one of the most pressing issues facing the world today. It significantly impacts forest distribution, species composition, stand structure, growth, and other functions, therefore, it is crucial to simulate the dynamic changes of forest structure under future climate change and develop optimized solutions to adapt to it. Combined with the various stand structural parameters, based on the equal or unequal weights of each parameter at the stand level, to establish a dynamic stand spatial structure multi-objective optimization index (L-index) under different climate changes, and to implement broadleaf mixed forest spatial structure optimization research in Yanan Forest Farm under RCP 2.6, RCP 4.5, RCP 8.5 climate scenarios after 5 years. The results indicated that the L-index showed an increase ranging from 13.8 % to 35.7 % under equal weights in different climate scenarios. Additionally, the optimal harvesting intensity ranged from 13.2 % to 20.5 %, with the highest intensity observed in the RCP4.5 climate scenario; compared to the RCP4.5 and RCP8.5 climate scenarios, the RCP2.6 scenario shows the largest trend and magnitude of change in the indicators, suggesting that the state of stand growth is more sensitive under the RCP2.6 scenario. The L-index showed an increase ranging from 13.7 % to 34.4 % under the unequal weights in different climate scenarios, in which the optimal harvesting intensity ranged from 14.6 % to 19.8 %. More importantly, it should be noted that the values of the increases in the L-index and the relative increased proportion (RIP) were both higher than those when unequal weights were employed. Moreover, it should be highlighted that the increments in the L-index and RIP were both greater than those observed when unequal weights were applied for all three plots under different climate scenarios. Overall, the adjusted the complete mixing degree index (Mc) increased, angle index (W), dominance ratio index (U), and Hegyi competition index (CI) decreased compared to before optimizing with the equal or unequal weights of the stand structural variable, which is evident that the adjustments made to the stand’s structure have resulted in a significant improvement. Thus, the multi-objective optimization for forest spatial dynamics constructed is both reasonable and effective, and it more scientific forest management under different climatic scenarios.

Investigation of tribological behavior of polytetrafluoroethylene/graphene composite

AbstractIn this study, we constructed molecular friction models for polytetrafluoroethylene (PTFE)/graphene composites with various defect ratios to represent their different wear stages and simulated their friction processes under different load conditions. The friction and wear mechanisms were revealed by analyzing the variations in their molecular architectures and energies during friction. The results indicate that the friction coefficient decreased with increasing load. When the load was constant, the friction coefficients of the composites containing defections were resemble, indicating that they remained unchanged in the different wear stages. The composite wear continued to increase during friction. However, the wear increment decreased gradually. In addition, by analyzing the changes in MSD, wear can be divided into initial, stable, and accelerated wear stages.Highlights Construct PTFE/Gr molecular models to represent their different wear stages. Simulate the dynamic changes of PTFE/Gr molecular structure during friction. The influence of PTFE/Gr dynamic structural changes was revealed. Reveal the normal force variation from an energy perspective.

Specific and Plastic: Chandelier Cell-to-Axon Initial Segment Connections in Shaping Functional Cortical Network.

Axon initial segment (AIS) is the most excitable subcellular domain of a neuron for action potential initiation. AISs of cortical projection neurons (PNs) receive GABAergic synaptic inputs primarily from chandelier cells (ChCs), which are believed to regulate action potential generation and modulate neuronal excitability. As individual ChCs often innervate hundreds of PNs, they may alter the activity of PN ensembles and even impact the entire neural network. During postnatal development or in response to changes in network activity, the AISs and axo-axonic synapses undergo dynamic structural and functional changes that underlie the wiring, refinement, and adaptation of cortical microcircuits. Here we briefly introduce the history of ChCs and review recent research advances employing modern genetic and molecular tools. Special attention will be attributed to the plasticity of the AIS and the ChC-PN connections, which play a pivotal role in shaping the dynamic network under both physiological and pathological conditions.

Deep-sea microorganisms-driven V5+ and Cd2+ removal from vanadium smelting wastewater: Bacterial screening, performance and mechanism

The disorderly discharge of industrial wastewater containing heavy metals has caused serious water pollution and ecological environmental risks, ultimately threatening human life and health. Biological treatment methods have obvious advantages, but the existing microorganisms exhibit issues such as poor resistance, adaptability, colonization ability, and low activity. However, a wide variety of microorganisms in deep-sea hydrothermal vent areas are tolerant to heavy metals, possessing the potential for efficient treatment of heavy metal wastewater. Based on this, the study obtained a group of deep-sea microbial communities dominated by Burkholderia-Caballeronia-Paraburkholderia through shake flask experiments from the sediments of deep-sea hydrothermal vents, which can simultaneously achieve the synchronous removal of vanadium and cadmium heavy metals through bioreduction, biosorption, and biomineralization. Through SEM-EDS, XRD, XPS, and FT-IR analyses, it was found that V(V) was reduced to V(IV) through a reduction process and subsequently precipitated. Glucose oxidation accelerated this process. Cd(II) underwent biomineralization to form precipitates such as cadmium hydroxide and cadmium carbonate. Functional groups on the microbial cell surface, such as -CH2, C=O, N-H, -COOH, phosphate groups, amino groups, and M-O moieties, participated in the bioadsorption processes of V(V) and Cd(II) heavy metals. Under optimal conditions, namely a temperature of 40 °C, pH value of 7.5, inoculation amount of 10%, salinity of 4%, COD concentration of 600 mg/L, V5+ concentration of 300 mg/L, and Cd2+ concentration of 40 mg/L, the OD600 can reach its highest at 72 h, with the removal efficiency of V5+, Cd2+, and COD in simulated vanadium smelting wastewater reaching 86.32%, 59.13%, and 61.63%, respectively. This study provides theoretical insights and practical evidence for understanding the dynamic changes in microbial community structure under heavy metal stress, as well as the resistance mechanisms of microbial treatment of industrial heavy metal wastewater.

Oxygen concentration regulated the efficient liquefaction of vulcanized natural rubber

Oxidative liquefaction represents a promising avenue for the homogeneous and high-value utilization of waste tire rubber. Given that truck tires predominantly comprise natural rubber (NR), this study investigated the efficient liquefaction of vulcanized NR regulated by oxygen concentration. Remarkably, the liquefaction of vulcanized NR was realized with an oxygen concentration of 75 % at 200 °C within 3 min. FTIR spectroscopy showed that carbonyl, ether and sulphoxide groups were produced during the liquification of NR vulcanizates. Oxygen concentration significantly affected the oxidative efficiency of both the main chains and crosslinks, with a more pronounced effect observed on the main chains. Nevertheless, the similar molecular weights and polydispersity indices across various degraded products suggested a selective oxidative cleavage of the NR backbone. Furthermore, online ATR-FTIR was used to monitor the dynamic changes of NR's molecular structure to elucidate the oxidative degradation mechanism. The oxidative cleavage of NR main chain primarily occurred at the C-C bonds connected with allyl groups, producing oxidized products enriched with conjugated carbonyl groups. Alternatively, the main chain scission may also occur due to the electronic rearrangement effect of the C=C bond and produce saturated carbonyl groups. Oxygen concentration modulated the degradation efficiency of vulcanized NR, which provided an efficient strategy for the upcycling of NR-based waste tires.

Evolving brain network dynamics in early childhood: Insights from modular graph metrics

Modular dynamic graph theory metrics effectively capture the patterns of dynamic information interaction during human brain development. While existing research has employed modular algorithms to examine the overall impact of dynamic changes in community structure throughout development, there is a notable gap in understanding the cross-community dynamic changes within different functional networks during early childhood and their potential contributions to the efficiency of brain information transmission. This study seeks to address this gap by tracing the trajectories of cross-community structural changes within early childhood functional networks and modeling their contributions to information transmission efficiency. We analyzed 194 functional imaging scans from 83 children aged 2 to 8 years, who participated in passive viewing functional magnetic resonance imaging sessions. Utilizing sliding windows and modular algorithms, we evaluated three spatiotemporal metrics—temporal flexibility, spatiotemporal diversity, and within-community spatiotemporal diversity—and four centrality metrics: within-community degree centrality, eigenvector centrality, between-community degree centrality, and between-community eigenvector centrality. Mixed-effects linear models revealed significant age-related increases in the temporal flexibility of the default mode network (DMN), executive control network (ECN), and salience network (SN), indicating frequent adjustments in community structure within these networks during early childhood. Additionally, the spatiotemporal diversity of the SN also displayed significant age-related increases, highlighting its broad pattern of cross-community dynamic interactions. Conversely, within-community spatiotemporal diversity in the language network exhibited significant age-related decreases, reflecting the network's gradual functional specialization. Furthermore, our findings indicated significant age-related increases in between-community degree centrality across the DMN, ECN, SN, language network, and dorsal attention network, while between-community eigenvector centrality also increased significantly for the DMN, ECN, and SN. However, within-community eigenvector centrality remained stable across all functional networks during early childhood. These results suggest that while centrality of cross-community interactions in early childhood functional networks increases, centrality within communities remains stable. Finally, mediation analysis was conducted to explore the relationships between age, brain dynamic graph metrics, and both global and local efficiency based on community structure. The results indicated that the dynamic graph metrics of the SN primarily mediated the relationship between age and the decrease in global efficiency, while those of the DMN, language network, ECN, dorsal attention network, and SN primarily mediated the relationship between age and the increase in local efficiency. This pattern suggests a developmental trajectory in early childhood from global information integration to local information segregation, with the SN playing a pivotal role in this transformation. This study provides novel insights into the mechanisms by which early childhood brain functional development impacts information transmission efficiency through cross-community adjustments in functional networks.

Spatio-temporal dynamics of phytoplankton community structure in the coastal waters of the Southern Beibu Gulf.

This study was conducted during October 2021 (autumn) and April 2022 (spring) to explore the phytoplankton community structure, their distribution characteristics, and the influence of environmental factors in the coastal waters of the Southern Beibu Gulf. The 15 sampling sites were grouped based on the difference in offshore distance to analyze the temporal and spatial differences in community structure and environmental driving in the investigated sea area of the coastal waters of the Southern Beibu Gulf. Permutational multivariate analysis of variance was conducted on the sample data in time and space, revealing that there is no significant difference in space (p > 0.05), but there is significant difference in time (p < 0.05). Notably, water pressure, pH, chemical oxygen demand, nitrite, and labile phosphate were higher in autumn, while total ammonia nitrogen, dissolved oxygen, and suspended solids were significantly higher in spring. Additionally, the study identified 87 phytoplankton species belonging to 6 phyla, dominating by Bacillariophyta, followed by Dinophyta and Cyanophyta. The phytoplankton density, Shannon Weiner's diversity index (H'), Pielou's evenness index (J), and Margalef's richness index (D) ranged from 84.88 to 4675.33 cells L-1, 0.56 to 2.58, 0.26 to 0.89, and 1.21 to 3.64, respectively. Permutational multivariate analysis of variance showed non-significant spatial differences in phytoplankton composition (p > 0.05) but seasonal differences (p < 0.05). Furthermore, canonical correspondence analysis (CCA) identified pH, dissolved oxygen, suspended solids, chemical oxygen demand, nitrite, and labile phosphate as key environmental factors influencing the phytoplankton community structure (p < 0.05). In this study, the dynamic changes of phytoplankton community structure and environmental factors in the southern coastal waters of Beibu Gulf were analyzed in detail from two aspects of time and space. The key environmental factors to protect the ecological environment in the southern coastal area of Beibu Gulf were found out. It provides a reference method and theoretical basis for the management and protection of Beibu Gulf and other tropical marine environment.

P-693 Three-dimensional modeling of follicular microenvironment dynamics in the human adult ovary

Abstract Study question How does the ovarian microenvironment, involving neural fibers, vascular networks, and immune cells, interplay with follicular dynamics in the human adult ovary? Summary answer Neural fibers growing into the ovarian cortex and vascular network expansion were associated with primordial follicle activation and growth. Macrophages associated with antral follicular atresia. What is known already The ovarian follicles, responsible for preserving and supplying oocytes, play a crucial role in fertility, with their fate influenced by the ovarian microenvironment. However, the three-dimensional (3D), irregular, and dynamic structural changes of the ovarian microenvironment are difficult to interpret using two-dimensional analysis. 3D-imaging technologies have been developed to reveal intricate structural and functional relationships particularly in rodents, but these approaches have not been widely adopted for human ovarian research. Study design, size, duration Our study aims to explore the follicular microenvironment dynamics in the human adult ovary. In this work, we optimized whole-mount immunofluorescence using TUBB3, PODXL, PECAM1, ACTA2 and CD68, and conducted 3D imaging on intact adult ovarian tissue, offering a visualization of the 3D structures and dynamic changes within ovarian follicles, neural fibers, vascular networks, and immune cells in human adult ovary at the single-cell level. Participants/materials, setting, methods The human ovarian samples were collected from donors (N = 5) who underwent oophorectomy after testosterone treatment. Part of the intact ovary, including cortex and medulla, was fixed and used for whole-mount immunofluorescence using markers for neural fibers (TUBB3), blood vessels (PODXL, PECAM1, ACTA2), and immune cells (CD68). Subsequently, an enhanced iDiSCO method was employed for tissue clearance. Finally, 3D images were acquired using a lightsheet microscope, followed by image analysis and 3D reconstruction using Imaris software. Main results and the role of chance Our results showed that TUBB3-labeled nerve fibers predominantly distributed in the ovarian cortex, with few presented in the medullary region. Notably, their presence surrounding secondary and antral follicles was limited. We observed a rich distribution of PODXL-labeled capillaries surrounding primordial and primary follicles in the cortical layer of the adult ovary. As follicles progressed to the secondary stage, PECAM1-labeled vasculature contributed to the construction of a vascular network enveloping the secondary follicles and connecting extensively to larger-caliber arteries containing (ACTA2+) smooth muscle cells. In antral follicles, large larger-caliber arteries were also detected, maintaining proximity to the theca cell layer. Interestingly, in cases of follicular atresia, vascular invasion within the follicular cavity was observed. Additionally, clusters of CD68+ macrophages exhibited a scattered distribution around the follicles at various stages, with a significant accumulation in atretic small-antral follicles. Limitations, reasons for caution Our study was conducted on ovaries from a limited number of donors after gender-affirming surgery. Although we aimed to provide insights into the ovarian microenvironment, we were so far unable to obtain ovaries with large antral follicles, ovulatory follicles and the formation of the corpus luteum. Wider implications of the findings The views provided by 3D-image analysis of the human ovary will augment the current knowledge of the complex interactions between the follicles and the ovarian microenvironment. 3D ovarian mapping will also provide a roadmap for generating oocytes in vitro for fertility preservation and ovarian disease modelling. Trial registration number N/A.

The impact of digital finance on young People's health insurance participation decisions in China.

The digital finance era has reshaped young people's lifestyles, risk perceptions and insurance participation decisions. Modern youth have to constantly seek for rational social security support and construct individual protection barriers to adapt to new lifestyles and social structures. China's multi-tiered, universal health insurance system is urgently needed to satisfy young people's flexible needs and rational decision-making. Based on the micro data from 2011 ~ 2021 Chinese General Social Survey (CGSS), this paper uses macro data from Digital Inclusive Finance Index (DIFI) matching to construct probit and m-logit model to assess the impact of the development of digital finance on Chinese youth whether or not to participate in health insurance, and how they choose the concrete type of health insurance. (1) Baseline regression results shows that digital finance has a significant positive effect on Chinese youth's health insurance participation decisions, and has different effects on choices within health insurance types. Strong support for the conclusions is provided by endogeneity and robustness tests. (2) The results of the heterogeneity analysis reveal that the marginal effect of digital finance on young people's health insurance decisions shows urban-rural differences, divergence in levels of self-rated health. (3) The mechanism analysis results suggest that there are two mechanism paths of digital finance on youth health insurance decisions: the household income effect and the subjective well-being effect, and two moderating effects: employment type and family structure. Highlighting the positive value that digital finance brings to the perception of youth insurance participation and the construction of social security systems, it needs to pay close attention to the dynamic changes in employment security and family structure through data, and explore the socio-psychological fluctuation and demand for social security among modern youth. To provide a way forward to achieve the integration of the health insurance system in China and solve the current problem of health insurance equity.