Triggering Mechanism Research Articles

Shaking table simulation of soft sediment deformation structures in lacustrine sediments

Soft sediment deformation structures (SSDSs) in lacustrine sediments could record paleoearthquakes in tectonically active areas. However, their interpretations of deformation and triggering mechanisms still exist disagreement due to the lack of understanding of natural formation processes of SSDSs. In this study, two large shaking table experiments of saturated lacustrine sedimentary sequences, including Model 1 (simple stratigraphic system of thick silty-clay and sand layer) and Model 2 (stratigraphic systems of thin silty-clay and sand alternating layers) were carried out at the different peak ground accelerations (PGA) in order to simulate the earthquake-triggered SSDSs on the basis of field investigation in Tashkorgan of western China. The results showed that there were no SSDSs formed at the PGA 0.125g, and the excess pore-water pressure ratio (γμ) measured in the sand layer was lower than 0.1; sand volcanos, pipes and sand veins were formed at the PGA 0.25g, and the γμ value of the sand layer reached about 0.2 with the maximum liquefied depths of nearly 30 cm, indicating that weak liquefaction occurred in the sand layer; sand volcanos, pipes, sand veins, diapirs, load and flame structures, ball-and-pillow structures, silty-clay deformation structures were formed at the PGA 0.5g and 0.8g, and the γμ value of sand layer reached about 0.91 and 0.94 with the maximum liquefied depths of nearly 60 cm and 100 cm, respectively. The γμ value of silty-clay layers measured in all the tests was lower than 0.1, indicating that little liquefaction but thixotropy happened in the silty-clay layers. The tests showed that liquefied SSDSs could form at the PGA 0.25g, while thixotropic and gravity-driven SSDSs could form until the PGA reached 0.5g. This study also provided insights for single or closely spaced shaking events being responsible of superposed deformed beds. The simulated SSDSs have striking resemblance to that of ones identified in the field, supporting the earthquake triggering of SSDSs in the Tashkorgan area.

Bacterial aggregation triggered by low-level antibiotic-mediated lysis

Suspended bacterial aggregates play a central role in ocean biogeochemistry, industrial processes and probably many clinical infections – yet the factors that trigger aggregation remain poorly understood, as does the relationship between suspended aggregates and surface-attached biofilms. Here we show that very low doses of cell-wall targeting antibiotic, far below the minimal inhibitory concentration, can trigger aggregation of Escherichia coli cells. This occurs when a few cells lyse, releasing extracellular DNA – thus, cell-to-cell variability in antibiotic response leads to population-level aggregation. Although lysis-triggered aggregation echoes known trigger mechanisms for surface-attached biofilms, these aggregates may have different ecological implications since they do not show increased biofilm-forming potential or increased antibiotic resistance. Our work contributes to understanding the nature of bacterial aggregates and the factors that trigger their formation, and the possible consequences of widespread low-dose antibiotic exposure in the environment and in the body.

Controllable heat release of supercooled Erythritol-based phase change materials for long-term thermal energy storage

Transeasonal heat storage in organic phase change materials (PCMs) present a promising solution to the intermittent nature of renewable energy. However, PCMs are prone to spontaneous crystallization during storage, leading to the loss of stored latent heat in low-temperature environments. In this study, we incorporated tetrasodium ethylenediaminetetraacetic acid (EDTA-4Na) and superabsorbent polymer (SAP) to erythritol (ERY), referred to as EES-PCMs, to overcome these challenges and achieve more controllable and stable thermal energy storage. The incorporation of EDTA-4Na and SAP into ERY significantly improves the supercooling stability and phase change enthalpy. The optimal ratio (EES-PCMs-2) of phase change enthalpy reaches an impressive 286.62 J/g, with stable performance maintained for 120 days at room temperature. The EES-PCMs-2 exhibits exceptional thermal cycling stability, retaining its properties even after 100 cycles. A novel air-triggered crystallization method is demonstrated, enabling a temperature increase from room temperature to 48.21 °C in 320 s after being exposed to air for long-term storage. This innovative approach effectively overcomes the limitations of traditional triggering mechanisms, providing a straightforward and efficient method for thermal management. The high thermal storage capacity, stability, and controlled exothermic properties of EES-PCMs position them as promising candidates for applications in seasonal solar thermal energy storage.

Severe acquired Factor VII deficiency complicating an aplastic anemia, successfully treated with corticosteroids.

Factor VII deficiency is a rare hemostatic disorder that can lead to severe clinical outcomes. Due to the scarcity of reported cases, treatment guidelines for this condition remain unclear. In this report, we present a case of acquired factor VII deficiency (aFVII) in an elderly female with medullary aplasia. The initial clinical manifestation was hemarthrosis, accompanied by a rapid increase in prothrombin time. Prompt intervention involved supplementation to address the deficiency. Subsequent laboratory testing failed to detect any specific factor VII inhibitor. Considering the patient's frailty, immunosuppressive therapy comprising only corticosteroids was administered. The potential triggering mechanisms may include recurrent episodes of sepsis or an underlying autoimmune condition. Further research is necessary to better understand the etiology and optimal management of aFVII deficiency.

Allosteric mechanism of membrane fusion activation in a herpesvirus.

Herpesviridae infect nearly all humans for life, causing diseases that range from painful to life-threatening1. These viruses penetrate cells by employing a complex apparatus composed of separate receptor-binding, signal-transmitting, and membrane-fusing components2. But how these components coordinate their functions is unknown. Here, we determined the 4.19-angstrom cryoEM reconstruction of the central signal-transmitting component from herpes simplex virus 2, the gH/gL complex, in its elusive pre-activation state. Analysis of the continuum of conformational ensembles observed in cryoEM data revealed a series of structural rearrangements in gH/gL that allosterically transmit the fusion-triggering signal from the receptor-binding glycoprotein gD to the membrane fusogen gB. Furthermore, we identified a structural "switch" element in gH/gL that refolds and flips 180 degrees during the transition from pre-activation to activated form. Conservation of this "switch" in gH/gL homologs suggests that the proposed fusion triggering mechanism may apply to all Herpesviridae and points to a new target for subunit-based vaccines and treatment efforts.

NaCl-induced effects on photosynthesis, ion relations, and growth of Chloris gayana Kunth in the presence of two levels of KCl

Soil salinization is a widespread environmental problem that impacts agriculture. Potassium fertilization is often associated with stress mitigation. Aiming to identify the ability of Rhodes grass (Chloris gayana Kunth) to cope with high salt as well as to investigate the potential of K+ fertilization to alleviate stress symptoms, we investigated the combined effects of NaCl and KCl on photosynthesis, ion distribution, and growth of two Rhodes grass cultivars, Callide and Reclaimer. Plants were grown under different regimes (0, 200, 400, and 600 mM NaCl + 1 or 10 mM KCl). For Reclaimer, 10 mM KCl induced positive effects in photochemistry under 0 and 200 mM NaCl, as illustrated by fluorescence transients OJIP-bands and JIP-test parameters. However, such improvements did not lead to superior biomass accumulation nor net photosynthesis compared to the corresponding treatments under 1 mM KCl, which may not justify KCl application. In Callide 10 mM KCl induced deleterious effects on photochemistry of plants under low NaCl levels. High salinity (600 mM) induced stress-triggered biomass reduction of up to 70% in both cultivars, but all plants remained photosynthetically active. Exposure of both cultivars to NaCl concentrations equal to or higher than 200 mM triggered response mechanisms such as the ability to accumulate inorganic solutes accounting to osmotic potential, stomata closure, and excretion (up to 70%) of the retained Na+ onto the leaf surface irrespective of KCl. Our data reinforce that Rhodes grass is an auspicious forage crop for saline environments and, therefore, in revegetation programs for saline soils pasture in subtropical regions.

SD-MDN-TM: A traceback and mitigation integrated mechanism against DDoS attacks with IP spoofing

Traceback has been very attractive against DDoS attacks with IP spoofing instead of traditional mitigation methods because attacks require removal near attackers, resulting in affecting legitimate traffic as little as possible. There have been some approaches dedicated to achieving effective traceback. However, existing approaches often modify protocols to apply to multi-domain scenarios, and the implemented mitigation usually lags behind traceback. Therefore, this paper proposes the Software-Defined Multi-Domain Network Tracer and Mitigator (SD-MDN-TM) to traceback and mitigate DDoS attacks with IP spoofing in multi-domain SDN scenarios. We apply systematic sampling and flow feature extraction based on the Count-Min Sketch data structure for the lightweight statistics collection of massive DDoS attack traffic. We also design the TracebackTree data structure to construct the traceback paths of attackers of distributed attack sources. The Border Switch Trigger Mechanism is proposed to overcome the drawbacks of the commonly-used packet marking in cross-domain traceback information transfer, achieving no modification of existing network protocols and independent traceback among multiple domains. Mitigation is integrated with traceback for faster removal of attacks from the network. The proposed scheme can traceback DDoS attack sources both inside and outside domains accurately and effectively by constructing traceback path. It can be implemented without modifying the existing protocols, therefore achieving direct application to the existing network architecture. Furthermore, the traceback of attack sources outside domains can maintain independence in multi-domain scenarios. Mitigation integrated with traceback can achieve less impact on legitimate traffic and faster removal of attacks from the network.

Permeability characteristics, structural failure characteristics, and triggering process of loess landslides in two typical strata structures

Landslides occurring at the interface of strata are among the most common forms of loess landslides in China. Statistics indicate that significant loess-red silty clay interface landslides induced by irrigation in the Heifangtai Platform than loess-paleosol interface landslides in the South Jingyang Platform. To uncover the permeability characteristics, structural failure patterns, and triggering processes of two typical strata structures. This study employs Nuclear Magnetic Resonance (NMR) and Scanning Electron Microscopy (SEM) techniques to investigate the permeability and structural failure of two soil combination types: loess-red silty clay and loess-paleosol. The results revealed a positive correlation between the stagnant water effect and flow rate, but a negative correlation with the initial water content. Notably, these two typical strata exhibited distinct differences in the stagnant water effect. In loess-red silty clay, continuous filling of mesopores and macropores by fine clay particles, while at the same time the agglomerates disintegration at the interface, thereby enhancing the stagnant water effect. In contrast, loess-paleosol exhibited good connectivity between the mosaic pores at the interface. This facilitated the formation of several elongated microcracks, which acted as dominant channels for infiltration and weakened the stagnant water effect. However, the macroscopic triggering mechanism for loess landslides in both loess-red silty clay and loess-paleosol combination strata remains similar. Irrigation water stagnates within the relatively impermeable layers, saturating and structurally damaging the bottom of loess layer, ultimately inducing landslides. These findings provide a scientific basis for the future study of loess landslide hazards in different strata structures, which is of great significance.

Emotion and cognition: on the cognitive processing model of nostalgia.

Nostalgia is a common emotional phenomenon, but its complexity has resulted in a limited understanding and interpretation. This study, grounded in emotional cognitive science, develops a cognitive processing model of nostalgia, encompassing its triggering mechanism, cognitive processes, and effects. The analysis indicates that nostalgia functions as an adaptive mechanism for individuals with deficiencies in belongingness and low-avoidance tendencies, helping them cope with disruptions in self-continuity by forging symbolic social bonds in a distant and idealized timespace. Essentially, nostalgia allows individuals to reconstruct alternate systems of meaning and value, which serve as references for defining self-worth and identity. This study advances the understanding of the complex cognitive processing involved in nostalgia and also provides an important reference for the study of complex emotions.

Autonomous Underwater Vehicle (AUV) Motion Design: Integrated Path Planning and Trajectory Tracking Based on Model Predictive Control (MPC)

This paper attempts to develop a unified model predictive control (MPC) method for integrated path planning and trajectory tracking of autonomous underwater vehicles (AUVs). To deal with the computational burden of online path planning, an event-triggered model predictive control (EMPC) method is introduced by using the environmental change as a triggering mechanism. A collision hazard function utilizing the changing rate of hazard as a triggering threshold is proposed to guarantee safety. We further give an illustration of how to calculate this threshold. Then, a Lyapunov-based model predictive control (LMPC) framework is developed for the AUV to solve the trajectory tracking problem. Leveraging a nonlinear integral sliding mode control strategy, we construct the contraction constraint within the formulated LMPC framework, thereby theoretically ensuring closed-loop stability. We derive the necessary and sufficient conditions for recursive feasibility, which are subsequently used to prove the closed-loop stability of the system. In the simulations, the proposed path planning and tracking control are verified separately and integrated and combined with static and dynamic obstacles.

Adaptive fuzzy performance control based on a triggering mechanism with decreasing function and internal dynamic variable

The problem of fuzzy adaptive prescribed performance control with dynamic event-triggered input for a class of uncertain nonlinear systems is investigated in this article. A dynamic event-triggered scheme is proposed that integrates an internal dynamic variable and an exponentially decreasing function, effectively reducing unnecessary trigger events and minimizing the system of communication resources. Subsequently, a fuzzy estimator is designed to estimate the unmeasurable states of the system, while fuzzy logic systems are employed to approximate the uncertain nonlinear terms. The proposed scheme ensures semi-globally uniformly ultimately bounded (SGUUB) of the closed-loop system and converges the tracking error to a prescribed performance range based on a barrier Lyapunov function. Finally, a simulation example is given to justify the rationality of the proposed strategy.

Distribution Characteristics and Genesis Mechanism of Ground Fissures in Three Northern Counties of the North China Plain

The North China Plain is among the regions most afflicted by ground fissure disasters in China. Recent urbanization has accelerated ground fissure activity in the three counties of the northern North China Plain, posing significant threats to both the natural environment and socioeconomic sustainability. Despite the increased attention, a lack of comprehensive understanding persists due to delayed recognition and limited research. This study conducted field visits and geological surveys across 43 villages and 80 sites to elucidate the spatial distribution patterns of ground fissures in the aforementioned counties. By integrating these findings with regional geological data, we formulated a causative model to explain ground fissure formation. Our analysis reveals a concentration of ground fissures near the Niuxi and Rongxi faults, with the former exhibiting the most extensive distribution. The primary manifestations of ground fissures include linear cracks and patch-shaped collapse pits, predominantly oriented in east-west and north-south directions, indicating tensile failure with minimal vertical displacement. Various factors contribute to ground fissure development, including fault activity, ancient river channel distribution, bedrock undulations, rainfall, and ground settlement. Fault activity establishes a concealed fracture system in shallow geotechnical layers, laying the groundwork for ground fissure formation. Additionally, the distribution of ancient river channels and bedrock undulations modifies regional stress fields, further facilitating ground fissure emergence. Rainfall and differential ground settlement serve as triggering mechanisms, exposing ground fissures at the surface. This research offers new insights into the causes of ground fissures in the northern North China Plain, providing crucial scientific evidence for sustaining both the natural environment and the socio-economic stability of the region.

High-resolution observations of recurrent jets from an arch filament system

Solar jets are collimated plasma ejections along magnetic field lines observed in hot (extreme-ultraviolet (EUV) jets) and cool (chromospheric surges) temperature diagnostics. Their trigger mechanisms and the relationship between hot and cool jets are still not completely understood. We aim to investigate the generation of a sequence of active-region solar jets and their evolution from the photospheric to the coronal heights using multithermal observations from ground-based and space-borne instruments. Using the synergy of high-spatial-resolution and high-temporal-resolution observations by the Swedish 1-m Solar Telescope (SST), along with the Solar Dynamics Observatory (SDO), we analyzed a sequence of solar jets originating in a mixed-polarity region between the leading and following sunspots of an active region. We investigated the kinematics of these jets using the spectra from the SST observations. We used a non-force-free field (NFFF) extrapolation technique to derive the magnetic field topology of the active region. A mixed-polarity region is formed over a long period (24 hours) with persistent magnetic flux emergence. This region has been observed as an arch filament system (AFS) in chromospheric SST observations. In this region, negative polarities surrounded by positive polarities create a fan surface with a null point at a height of 6 Mm detected in the NFFF extrapolation. SST observations in the Hbeta spectral line reveal a large flux rope over the AFS moving from north to south, causing successive EUV and cool jets to move in the east--west direction and later towards the south along the long open loops. The high-resolution SST observations (0 per pixel) resolve the dark area observed at the jet base and reveal the existence of an AFS with an extended cool jet, which may be the result of a peeling-like mechanism of the AFS. Based on the combined analysis of SST and AIA observations along with extrapolated magnetic topology, it is suggested that the magnetic reconnection site may move southward by approximately 20 Mm until it reaches a region where the open magnetic field lines are oriented north--south.

Trigger mechanism for a singing cavitating tip vortex

The discrete tone radiated from tip vortex cavitation (TVC), known as ‘vortex singing’, was recognized in 1989, but its triggering remains unclear for over thirty years. In this study, the desinent cavitation number and viscous correction are applied to describe the dynamics of cavitation bubbles and the dispersion relation of cavity interfacial waves. The wavenumber-frequency spectrum of the cavity radius from the experiment in CSSRC indicates that singing waves predominantly consist of the stationary double helical modes (kθ = 2- and -2+) and the breathing mode (kθ = 0-), rather than standing waves as assumed in previous literatures. Moreover, two trigger mechanisms, expressed by two triggering lines, are proposed: the twisted TVC, initially at rest, is driven into motion through the corrected natural frequency (fn) due to the step change of the far-field pressure. Subsequently, the frequency associated with the zero-group-velocity point (ῶzgv) at kθ = 0- is excited through ῶi, the frequency at the intersection of dispersion curves at kθ = 0- and -2+, or ῶj, the frequency at the intersection of dispersion curves at kθ = 0- and 2-, corresponding to two types of the vortex singing triggering. These solutions, without empirical parameters, are validated using singing conditions provided by CSSRC and G.T.H., respectively. Furthermore, the coherence and the cross-power spectral density spectrum indicates a large-scale breathing wave propagating along the singing cavity surface and travelling from downstream to hydrofoil tip, providing us a comprehensive understanding for the triggering of vortex singing.

Effect of Continuous Cropping on Growth and Lobetyolin Synthesis of the Medicinal Plant Codonopsis pilosula (Franch.) Nannf. Based on the Integrated Analysis of Plant-Metabolite-Soil Factors.

The integrated plant-metabolite-soil regulation model of C. Pilosula growth and lobetyolin synthesis in response to continuous cropping lacks systematic investigation. In this study, we investigated the regulatory mechanisms of growth and lobetyolin synthesis in C. pilosula under continuous cropping stress based on high-performance liquid chromatography, transcriptome, and microbial sequencing on the root system and rhizosphere soil of C. pilosula from one year of cultivation and five years of continuous cropping. The findings of this study revealed that continuous cropping significantly inhibited the growth of C. pilosula and led to a notable decrease in the lobetyolin content. An effort was made to propose a potential pathway for lobetyolin biosynthesis in C. pilosula, which is closely linked to the expression of genes responsible for glucoside and unsaturated fatty acid chain synthesis. In addition, soil physicochemical properties and soil microorganisms had strong correlations with root growth and synthesis of lobetyolin, suggesting that soil physicochemical properties and microorganisms are the main factors triggering the succession disorder in C. pilosula. This study provides an in-depth interpretation of the regulatory mechanism of acetylenic glycoside synthesis and offers new insights into the triggering mechanism of C. pilosula succession disorder, which will guide future cultivation and industrial development.

Global analysis of social learning’s archetypes in natural resource management: understanding pathways of co-creation of knowledge

Although social learning (SL) conceptualization and implementation are flourishing in sustainability sciences, and its non-rigid conceptual fluidity is regarded as an advantage, research must advance the understanding of SL phenomenon patterns based on empirical data, thus contributing to the identification of its forms and triggering mechanisms, particularly those that can address urgent Anthropocene socio-ecological problems. This study aims to discover fundamental patterns along which SL in natural resources management differs by identifying SL archetypes and establishing correlations between the SL process and overall geopolitical conditions. Using a systematic literature review comprising 137 case studies in the five continents, content analysis, and correlations were performed. Results show two main archetypes of social learning (endogenous and exogenous). Their occurrence was linked, to where social learning occurs and how venues/preconditions for social learning are placed. In the Global South, endogenous SL should be better potentialized as a catalyzer of deliberative processes for sustainable natural resources management.

Crystals and melt inclusions record deep storage of superhydrous magma prior to the largest known eruption of Cerro Machín volcano, Colombia

Abstract Cerro Machín, a volcano located in the northern segment of the Andes, is considered one of the most dangerous volcanoes in Colombia with an explosive record that involves at least five plinian events. Prior studies focused on the last dome-building eruption have suggested the presence of a water-rich mid-crustal magma reservoir. However, no direct volatile measurements have been published and little work has been completed on the explosive products of the volcano. Here, we study the largest known eruption of Cerro Machín volcano which occurred 3600 yr BP producing dacitic pyroclastic fall deposits that can be traced up to 40 km from the vent. Lapilli pumice clasts have a mineral assemblage of plagioclase, amphibole, quartz, and biotite phenocrysts, with accessory olivine, Fe-Ti oxides, and apatite. The occurrence of Fo89-92 olivine rimmed by high Mg# amphibole and the established high-water contents in the magma imply the presence of magma near or at water saturation at pressures >~500 MPa. Measurements of up to 10.7 wt% H2O in melt inclusions hosted in plagioclase and quartz in the 3600 years BP eruption products support the idea that Cerro Machín is a remarkably water-rich volcanic system. Moreover, this is supported by measurements of ~103 – 161 ppm H2O in plagioclase phenocrysts. The application of two parameterizations of water partitioning between plagioclase and silicate melt allows us to use our water in plagioclase measurements to estimate equilibrium melt water contents of 5 ± 1 – 11 ± 2 wt% H2O, which are in good agreement with the water contents we measured in melt inclusions. Results of amphibole geobarometry are consistent with a magma reservoir stored in the mid-to-lower crust at a modal pressure of 700 ± 250 MPa, corresponding to a depth of ~25 km. Minor crystallization in the shallow crust is also recorded by amphibole barometry and calculated entrapment pressures in melt inclusions. Amphibole is present as unzoned and zoned crystals. Two populations of unzoned amphibole crystals are present, the most abundant indicate crystallization conditions of 853 ± 26 °C (1 se; standard error), and the less abundant crystallized at an average temperature of 944 ± 24 °C (1 se). Approximately 18% of the amphibole crystals are normally or reversely zoned, providing evidence for a minor recharge event that could have been the trigger mechanism for the explosive eruption. Plagioclase crystals also show normal and reverse zoning. The moderate Ni concentrations (<1600 μg/g) in the high-Fo olivine xenocrysts suggest that Cerro Machín primary magmas are generated by inefficient interaction of mantle peridotite with a high-silica melt produced by slab melting of basaltic material. Some sediment input is also suggested by the high Pb/Th (>2.2), Th/La (0.3 – 0.4), and low La/Th (<13; relative to mantle array) ratios. Whole rock chemistry reveals heavy rare earth element (HREE) depletion and Sr enrichment that likely formed during the crystallization of garnet and amphibole in the upper part of the mantle or lower portion of the crust, promoting the formation of water-rich dacitic magma that was then injected into the middle-to-lower crust. Textural and compositional differences in the crystal cargo that erupted during dome-building and plinian events support the idea that large volumes of magma recharge lead to effusive eruptions, while only small recharge events are needed to trigger plinian eruptions at Cerro Machín.

Dust and power: Unravelling the merger-active galactic nucleus connection in the second half of cosmic history

Galaxy mergers represent a fundamental physical process under hierarchical structure formation, but their role in triggering active galactic nuclei (AGNs) is still unclear. We aim to investigate the merger-AGN connection using state-of-the-art observations and novel methods for detecting mergers and AGNs. We selected stellar mass-limited samples at redshift $z<1$ from the Kilo-Degree Survey (KiDS), focussing on the KiDS-N-W2 field with a wide range of multi-wavelength data. We analysed three AGN types, selected in the mid-infrared (MIR), X-ray, and via spectral energy distribution (SED) modelling. To identify mergers, we used convolutional neural networks (CNNs) trained on two cosmological simulations. We created mass- and redshift-matched control samples of non-mergers and non-AGNs. We first investigated the merger-AGN connection using a binary AGN/non-AGN classification. We observed a clear AGN excess (of a factor of $2-3$) in mergers with respect to non-mergers for the MIR AGNs, along with a mild excess for the X-ray and SED AGNs. This result indicates that mergers could trigger all three types, but are more connected to the MIR AGNs. About half of the MIR AGNs are in mergers but it is unclear whether mergers are the main trigger. For the X-ray and SED AGNs, mergers are unlikely to be the dominant triggering mechanism. We also explored the connection using the continuous AGN fraction $f_ AGN $ parameter. Mergers exhibit a clear excess of high $f_ AGN $ values relative to non-mergers, for all AGN types. We unveil the first merger fraction $f_ merger - f_ AGN $ relation with two distinct regimes. When the AGN is not very dominant, the relation is only mildly increasing or even flat, with the MIR AGNs showing the highest $f_ merger $. In the regime of very dominant AGNs ($f_ AGN merger $ shows the same steeply rising trend with increasing $f_ AGN $ for all AGN types. These trends are also seen when plotted against AGN bolometric luminosity. We conclude that mergers are most closely connected to dust-obscured AGNs, generally linked to a fast-growing phase of the supermassive black hole. Such mergers therefore stand as the main (or even the sole) fuelling mechanism of the most powerful AGNs.

Differential immunological profiles in seronegative versus seropositive rheumatoid arthritis: Th17/Treg dysregulation and IL-4.

Rheumatoid arthritis (RA) is an autoimmune disease with various subtypes. Among these, seronegative rheumatoid arthritis (SnRA), distinguished by its distinctive seronegative antibody phenotype, presents clinical diagnosis and treatment challenges. This study aims to juxtapose the immunological features of SnRA with seropositive rheumatoid arthritis (SpRA) to investigate potential mechanisms contributing to differences in antibody production. This study included 120 patients diagnosed with RA and 78 patients diagnosed with psoriatic arthritis (PsA), comprising 41 cases of SnRA and 79 cases of SpRA. Clinical, serological, and immune data were collected from all participants to systematically identify and confirm the most pivotal immunological distinctions between SnRA and SpRA. (1) SpRA demonstrates more pronounced T-helper 17 cells (Th17)/Regulatory T cells (Treg) dysregulation, vital immunological differences from SnRA. (2) SpRA exhibits higher inflammatory cytokine levels than SnRA and PsA. (3) Lymphocyte subset ratios and cytokine overall distribution in SnRA close to PsA. (4) Interleukin-4 (IL-4) emerges as the central immunological disparity marker between SnRA and SpRA. Th17/Treg imbalance is one of the vital immunological disparities between SnRA and SpRA. Interestingly, PsA and SnRA display similar peripheral blood immunological profiles, providing immunological evidence for these two diseases' clinical and pathological similarities. Furthermore, IL-4 emerges as the central immunological disparity marker between SnRA and SpRA, suggesting its potential role as a triggering mechanism for differential antibody production.

Inflammatory microenvironment-responsive “double-insurance” nanoreactors for accurate sonodynamic-chemodynamic therapy of rheumatoid arthritis

Rheumatoid arthritis is a systemic autoimmune disease, and the development of an accurate treatment modality that combines excellent efficacy with low toxicity is still a daunting challenge. Herein, we design copper ion-doped ZIF-8 nanoreactors loaded with Cu(II)Ce6 and BSA-MnO2 (BMCC), which has a “double-insurance” triggering mechanism for accurate sonodynamic and chemodynamic synergistic treatment of rheumatoid arthritis. The copper ion-doped ZIF-8 shell is degraded in the uniquely acidic microenvironment of inflamed joints, with 95.56 % releasing of Cu(II)Ce6 at pH 6.5. Dynamically limited Cu(II)Ce6 restores dynamic properties when Cu(II)Ce6 reacts with cysteine overexpressed at inflamed joints to generate Cu(I)Ce6. The loaded BSA-MnO2 nanoparticles are able to react with hydrogen peroxide to generate oxygen under acidic conditions, providing a source of oxygen to enhance sonodynamic therapy. Cu2+ released from the decomposition of ZIF-8 nanoreactors undergone a Fenton-like reaction with H2O2 and cysteine to produce ·OH for chemodynamic therapy. In the mouse model of collagen-induced arthritis, the BMCC presents an effective inhibitory effect and excellent biosecurity on rheumatoid arthritis. These results indicate that the BMCC with inflammatory microenvironment-responsive “double-insurance” mechanism possesses a very high biosafety and offers a promising prospect for accurate and efficient treatment of rheumatoid arthritis.