Search Results (133)

Adventitious shoot regeneration in woody species is regulated by interactions between plant growth regulators, endogenous hormone metabolism, and environmental cues such as light quality. Here, we investigated the effects of thidiazuron (TDZ) and the cytokinin oxidase/dehydrogenase (CKX) inhibitors INCYDE and phenyladenine (PA), in combination with different light spectra, on morphogenesis in Melia volkensii leaf explants. TDZ induced the highest frequencies of callus formation and adventitious shoot regeneration, particularly under white light. INCYDE promoted localized regeneration responses, including activation of dormant meristematic regions in secondary leaf axils, whereas PA showed limited regeneration efficiency. Light quality significantly influenced morphogenesis, with white and blue light favoring organized shoot development, while red and far-red light suppressed shoot regeneration and promoted callus formation. Cytokinin profiling revealed treatment-dependent shifts in endogenous cytokinin composition, most notably in isopentenyladenine (iP)-type cytokinins, which is consistent with altered cytokinin degradation dynamics. Cis-zeatin-type cytokinins were abundant across treatments, likely reflecting regulation associated with in vitro culture conditions. These findings indicate that cytokinin metabolism and light quality jointly influence organogenic competence in Melia volkensii Gürke, providing a physiological basis for optimizing regeneration strategies in woody plants. This study provides the first integrated analysis of cytokinin-modulating compounds and light spectra on adventitious shoot regeneration in Melia volkensii. The findings establish a physiological basis for improving regeneration protocols in recalcitrant woody species and support future biotechnological applications, including genetic improvement and advanced propagation strategies. Full article

In type 1 diabetes (T1D) in non-obese diabetic (NOD) mice, dendritic cells (DCs) exhibit a Stat5b mutation that impairs regulatory T cell (Tregs) numbers and suppressive function. To correct this defect, we generated transgenic NOD mice expressing constitutively active Stat5b (NOD.Stat5b-CA) in DCs, which conferred protection from diabetes that was associated with an expanded Treg population and a marked reduction in CD8⁺ T cell frequencies in secondary lymphoid organs. However, the phenotypic characteristics and underlying mechanisms to eliminate CD8⁺ T cells in NOD.Stat5b-CA mice are unknown. In this study, we found that the frequency of Tregs was significantly higher in the thymus and peripheral lymphoid organs of NOD.Stat5b-CA mice compared with NOD mice. Tregs in the peripheral lymphoid organs exhibited increased expression of activation markers CD69 and OX40, alongside reduced CD62L. We also found that CD8⁺ T cell frequencies were reduced in the peripheral organs but not in the thymus of NOD.Stat5b-CA mice, while CD4⁺ T cell frequencies remained unchanged across all organs. Furthermore, NOD.Stat5b-CA mice exhibited a reduced frequency of central Tregs (CD62L^high CD44^low) and increased frequency of effector Tregs (CD62L^low CD44^high) under steady-state conditions compared to NOD mice. Notably, Tregs from NOD.Stat5b-CA mice displayed enhanced cytotoxic activity, evidenced by increased expression of perforin, granzyme B, and Fas ligand, potentially mediating CD8⁺ T cell frequency reduction. Collectively, these findings highlight a novel role for Stat5b-CA.DC-educated Tregs in modulating immune responses by eliminating peripheral pathogenic CD8⁺ T cells via cytotoxic pathways, thereby contributing to immune regulation in NOD.Stat5b-CA mice. Full article

This paper proposes a fixed frequency pulse width modulation (PWM) for a dual active half-bridge resonant converter. The wide voltage range can be achieved without adding any additional components, and the voltage gain characteristic is independent of the load. Meanwhile, all switches can achieve full range zero voltage switching (ZVS). The driving logic is unified between the primary and secondary sides, allowing for the implementation of both boost and buck modes. Hence, the control logic is simple. In addition, the multiple-order harmonic analysis of the resonant tank is proposed without complex time-domain calculations. Hence, the expression of voltage gain, current characteristics, and soft switching conditions can be conveniently analyzed. Finally, a 500 W experimental prototype was built. The experimental results prove the effectiveness and superiority of the proposed solution. Full article

The Ulva prolifera green tide in the South Yellow Sea has erupted annually for many years, posing significant threats to coastal ecology, the economy, and society. While environmental factors are widely acknowledged as prerequisites for these outbreaks, the asynchrony and complex coupling between their variations and disaster events have challenged traditional studies that rely on instantaneous correlations to uncover the underlying dynamic mechanisms. This study focuses on the Ulva prolifera disaster in the South Yellow Sea, systematically analyzing its spatiotemporal distribution patterns, the temporal accumulation and lag effects of environmental factors, and the coupled driving mechanisms using the Floating Algae Index (FAI). The results indicate that: (1) The disaster shows significant interannual variability, with 2019 experiencing the most severe outbreak. Monthly, the disaster begins offshore of Jiangsu in May, moves northward and peaks in June, expands northward with reduced scale in July, and largely dissipates in August. Years with large-scale outbreaks exhibit higher distribution frequency and broader spatial extent. (2) Environmental factors demonstrate significant accumulation and lag effects on Ulva prolifera disasters, with a mixed temporal mode of both accumulation and lag effects being dominant. Temporal parameters vary across different factors—nutrients generally have longer lag times, while light and temperature factors show longer accumulation times. These parameters change dynamically across disaster stages and display a clear inshore–offshore gradient, with shorter effects in coastal areas and longer durations in offshore waters, revealing significant spatiotemporal heterogeneity in temporal response patterns. (3) The driving mechanism of Ulva prolifera disasters follows a “nutrient-dominated, temporally relayed” pattern. Nutrient accumulation (PO₄, NO₃, SI) from the previous autumn and winter serves as the decisive factor, explaining 86.8% of interannual variation in disaster scale and 56.1% of the variation in first outbreak timing. Light and heat conditions play a secondary modulating role. A clear temporal relay occurs through three distinct stages: the initial outbreak triggered by nutrients, the peak outbreak governed by light–temperature–nutrient synergy, and the system decline characterized by the dissipation of all driving forces. These findings provide a mechanistic basis for developing predictive models and targeted control strategies. Full article

Multiscale optical imaging is expected to address the trade-off between field of view (FOV) and resolution in optical systems. To achieve high resolution imaging with a large FOV, this study employs a double-layer monocentric lens to design the front-stage objective lens and utilizes multiple relay lenses for the secondary system. The design results demonstrate that the RMS value of the image spot size across the full FOV is controlled within 2 μm, and the system’s optical modulation transfer function (MTF) across the full FOV approaches the diffraction limit. Specifically, the MTF values across the full FOV exceed 0.35 at the cutoff frequency of 250 lp/mm. The designed optical system features a simple structure and high imaging quality. When a larger number of secondary relay imaging systems are employed, it is capable of achieving a large FOV with high resolution imaging performance, as required by the optical system. Moreover, it holds significant application potential in wide-area, large-range imaging and related fields. Full article

Secondary somatic embryogenesis (SSE) represents a powerful tool for clonal propagation, efficient genetic modification, and plant conservation, enabling the continuous production of secondary somatic embryos (SSEs) from previously formed embryogenic tissues. The efficiency of SSE is determined both by external factors such as exogenous hormonal and environmental conditions and internal cues such as explant type and genotype. Auxins, particularly synthetic 2,4-dichlorophenoxyacetic acid (2,4-D), represent key factors in inducing and maintaining embryogenic competence, while cytokinins often modulate the differentiation and proliferation of SSEs. The interplay of plant growth regulators (PGRs) not only affects the frequency of SSE induction, but also the morphology and proper development of the resulting embryos. Here, we provide a comprehensive review on hormonal treatments, especially the role of auxins and cytokinins and environmental factors such as temperature, light, and culture medium composition, that shape the embryogenic potential in SSE, with species-specific responses frequently being observed. The importance of primary explant selection, as well as the liquid phase and potential scale-up with bioreactors, are also discussed. Other challenges related to genotype recalcitrance, limited efficiency, maturation and conversion rates, and the lack of an advanced molecular approach are further addressed, providing a framework for improved regeneration and reliability across diverse species. Full article

This paper presents a high-efficiency wireless power transfer (WPT) architecture employing a resonant inductive coupling to power smart sensor nodes in remote or sealed environments, where conventional power delivery is unfeasible. The system integrates a photovoltaic (PV) energy source with a step-down DC-DC converter based on the LM2596 buck regulator to adjust the voltage from the PV. The proposed conditioned power system supplies the entire electronic circuit consisting of a PWM modulator based on an NE555, which drives an IR2110 gate driver connected to a Class D power amplifier. The amplifier excites a pair of high-Q resonant coils designed for mid-range inductive coupling. On the receiver side, the inductively coupled AC signal is rectified and regulated through an AC-DC conversion stage to charge a secondary energy storage unit. The design eliminates the need for physical electrical connections, ensuring efficient, contactless energy transfer. The proposed system operates at a resonant frequency of 24.46 kHz and achieves up to 80% transmission efficiency at a distance of 113 mm. The receiver provides a regulated DC output between 4.80 V and 4.97 V, sufficient to power low-consumption smart sensors. Full article

Research Subject: Primary and secondary immunodeficiencies represent a growing clinical and public health challenge due to increased susceptibility to infections, impaired immune regulation, chronic inflammation, and disturbances in redox homeostasis. The pathophysiology of these disorders involves dysfunction of innate and adaptive immunity, altered cytokine production, oxidative stress, and reduced activity of antioxidant defense mechanisms. In recent years, attention has increasingly focused on the role of oxidative imbalance and chronic inflammation in weakening immune function. Ozone therapy, when used at controlled low doses, induces a hormetic response that triggers adaptive antioxidant pathways, modulates cytokine profiles, and enhances the activity of immune cells. Due to these properties, ozone has emerged as a potential adjunctive therapy aimed at restoring immune homeostasis and improving clinical outcomes in patients with immune disorders. Aim of Study: The aim of this review is to discuss the role of oxidative stress and immune dysregulation in the pathogenesis of immunodeficiencies and to provide an updated overview of current evidence regarding the therapeutic potential of ozone therapy. This article summarizes molecular mechanisms, biochemical effects, and clinical findings related to ozone-based interventions, with particular emphasis on cytokine modulation, redox balance, macrophage function, regulatory T cells (Treg), and NK cell activity. Materials and Methods: This review is based on scientific data retrieved from PubMed, Scopus, and Google Scholar. Included sources comprise randomized clinical trials, observational studies, meta-analyses, mechanistic studies, and review articles published between 1996 and 2025. Keywords used during the literature search included: “ozone therapy”, “immunomodulation”, “oxidative stress”, “inborn errors of immunity”, “secondary immunodeficiency”, “Treg cells”, “redox homeostasis”. Results: Analysis of current studies shows that controlled low-dose ozone (typically 10–40 µg/mL) activates the Nrf2/ARE antioxidant pathway, increases enzymatic defense (SOD, catalase, GPx), and reduces levels of proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. Clinical trials report improved lymphocyte profiles, enhanced macrophage phagocytic function, increased Treg activity, and reinforced NK cell responses. Patients receiving ozone therapy demonstrate reductions in inflammatory markers (CRP, IL-6, D-dimer), improved redox balance, decreased infection frequency, and better overall immune performance. The therapy is generally well tolerated when administered within established safety guidelines. Conclusions: Available evidence indicates that ozone therapy may serve as a valuable adjunct in the management of immunodeficiencies by modulating immune responses, reducing oxidative stress, and restoring homeostatic balance. Although current clinical outcomes are promising, further multicenter randomized trials are needed to standardize dosing protocols, assess long-term effectiveness, and confirm safety. Full article

With the integration of high-penetration new energy, the increasing disparities in power source structures across interconnected power system control areas have become prominent. In some control areas, the growing share of new energy and reduced conventional generation units lead to higher frequency regulation demands but diminished control capabilities. The traditional control performance standard (CPS) under tie-line power and frequency bias control (TBC) mode defines evaluation thresholds using frequency deviation coefficients, but fails to account for the impact of the actual power source structures in different control areas. This inadequacy becomes increasingly evident in the new-energy-dominated power systems. This study first analyzes the assumptions and principles of existing CPS, revealing its limitations in high-proportion new-energy systems. Subsequently, the concept of inherent area control error (ACE) standard deviation is proposed to determine evaluation thresholds, forming an improved CPS methodology. Finally, the case studies show that the refined approach ensures greater fairness and rationality compared with the original CPS. Full article

Thigmomorphogenesis denotes a suite of anatomical, physiological, biochemical, biophysical, and molecular responses of plants to mechanical stimulation. This phenomenon is evolutionarily conserved among diverse plant lineages; however, the magnitude and character of the response are strongly determined by both the frequency and intensity of the applied stimulus. In angiosperms, thigmomorphogenetic reactions typically occur gradually, reflecting a complex interplay of morphological alterations, biochemical adjustments, and genetic reprogramming. In dicotyledonous plants, thigmomorphogenesis is commonly expressed as a reduction in leaf blade surface area, shortening of petioles, decreased plant height, radial thickening of stems, and modifications in root system architecture. In monocotyledons, in turn, mechanical stress frequently results in stem rupture below the inflorescence, with concomitant shortening and increased flexibility of younger internodes. These specific traits can be explained by structural features of monocot secondary walls as well as by the absence of vascular cambium and lateral meristems. Mechanical stimulation has been shown to initiate a cascade of responses across multiple levels of plant organization. The earliest events involve activation of mechanoresponsive genes (e.g., TCH family), followed by enzymatic activation, biochemical shifts, and downstream physiological and molecular adjustments. Importantly, recent findings indicate that prolonged mechanical stress may significantly suppress auxin biosynthesis, while leaving auxin transport processes unaffected. Moreover, strong interdependencies have been identified between thigmostimulation, gibberellin biosynthesis, and flowering intensity, as well as between mechanical stress and signaling pathways of other phytohormones, including abscisic acid, jasmonic acid, and ethylene. At the molecular scale, studies have demonstrated a robust correlation between the expression of specific calmodulin isoforms and the GH3.1 gene, suggesting a mechanistic link between mechanosensing, hormone homeostasis, and regulatory feedback loops. The present study consolidates current knowledge and integrates novel findings, emphasizing both morphological and cellular dimensions of thigmomorphogenesis. In particular, it provides evidence that mechanical stress constitutes a critical modulator of hormonal balance, thereby shaping plant growth, development, and adaptive potential. Full article

The Bell–Bloom magnetometer is promising for mobile applications, but its accuracy is limited by heading errors. A recently identified source of such error is a phase shift in the magnetic resonance, which arises from the superposition of two signals, i.e., the primary resonance from synchronous pumping and a secondary resonance, 90° out-of-phase, driven by the AC light shift of the pump laser. Through Bloch equation modeling and experiment, we uncover a counter-intuitive mechanism: although initiated by the AC light shift, the phase shift’s magnitude is determined solely by the pump light’s average power (DC component) and is independent of its AC modulation. This occurs because the amplitude ratio of the two resonances depends exclusively on the DC-power-induced atomic polarization. Based on this insight, we propose a novel DC compensation scheme by adding a continuous counter-polarized beam to cancel the net DC pumping. Theoretically, this simultaneously suppresses both the AC-light-shift-induced phase shift and the DC-light-shift-induced frequency shift. The scheme’s advantage is its simplified approach to polarization control, avoiding the need for high-speed polarization modulation or major hardware changes as the beams share the same optical path. This makes it highly suitable for demanding mobile applications like aerial magnetic surveying and wearable bio-magnetic sensing in unshielded environments. Full article

This study presents a pulse generator employing a saturable pulse transformer (SPT) in conjunction with a fast recovery diode, integrated within an all-solid-state pulse-forming network (PFN). The saturation inductance of the SPT serves as a component of the initial LC section of the PFN, thereby contributing to the preservation of output waveform integrity. The secondary energy storage capacitor is charged through the primary circuit and the SPT, subsequently discharging into the load under the regulation of the SPT. An increase in the SPT’s transformation ratio corresponds to a rise in its saturated inductance, which in turn prolongs the pulse rise time. To mitigate this effect, a fast recovery diode is incorporated to sharpen the pulse front. Specifically, upon saturation of the SPT, current reverses through the fast recovery diode, effectively short-circuiting the load. When the inductor current attains a predetermined threshold, the diode reverts to reverse cut-off and rapidly switches off, enabling the PFN to discharge swiftly into the load and generate a high-voltage pulse characterized by a rapid rising edge. Furthermore, augmenting the number of secondary windings on the SPT—each connected to a PFN module—and arranging multiple PFNs in series facilitates an increase in output voltage. Experimental evaluations demonstrated that a three-stage PFN pulse generator attained a peak voltage of −16.9 kV on an 80 Ω matched load, with pulse currents exceeding 200 A while maintaining a 19 ns front edge. These results indicate that the proposed approach is effective for producing high-voltage, narrow pulses with rapid rise times. Additionally, the pulse power generator is capable of delivering repetitive pulses of −16.9 kV at a frequency of 20 kHz in burst mode. Full article

Background: As we age, our autonomic function declines, resulting in altered autonomic balance during postural transitions. These changes can affect the dynamic interplay between sympathetic and parasympathetic modulation, compromising short-term compensatory responses to active standing. Objectives: This study aimed to compare heart rate variability (HRV) at baseline, cardiac parasympathetic modulation (CPM), and cardiac baroreflex gain (CRG) between younger adults (YA) and older adults (OA) following active standing orthostatic stress. A secondary objective was to analyze the incidence of orthostatic intolerance (OI) symptoms. Methods: Participants (n = 76) completed sit-to-stand and lie-to-stand maneuvers with continuous beat-to-beat blood pressure and heart rate (HR, electrocardiogram). HRV at baseline was analyzed in both time and frequency domains. CPM was measured by the HR 30:15 ratio on standing. CBG was determined as the ratio of HR and SBP changes (ΔHR/ΔSBP) at specific phase time points (30 s, 60 s, 180 s, and 420 s). Results: At baseline, OA showed reduced Standard Deviation of RR intervals (SDRR), Root Mean Square of Successive Differences (RMSSD), low-frequency (LF), and high-frequency (HF) power, and elevated LF/HF ratio (all p < 0.05), indicating a shift toward sympathetic dominance. During active standing orthostatic stress, OA demonstrated a lower HR30:15 ratio and CBG in later phases (phases 2–4) (all p < 0.05). Also, OA reported more symptoms (14%) of OI than YA (0%) (p = 0.041). Conclusions: These findings indicate that older adults have impaired autonomic function characterized by reduced HRV, CPM and CBG responses. These impairments lead to diminished autonomic regulation under active-standing orthostatic stress and a higher incidence of OI symptoms. Full article

This paper presents the design and implementation of a high-efficiency, full silicon carbide (SiC)-based center-tapped phase-shifted full-bridge (PSFB) converter for NiCd battery charging applications in railway systems. The converter utilizes SiC MOSFET modules on the primary side and SiC diodes on the secondary side, resulting in significant efficiency improvements due to the superior switching characteristics and high-temperature tolerance inherent in SiC devices. A nanocrystalline-cored center-tapped transformer is optimized to minimize voltage stress on the rectifier diodes. Additionally, the use of a nanocrystalline core provides high saturation flux density, low core loss, and excellent permeability, particularly at high frequencies, which significantly enhances system efficiency. The converter also compensates for temperature fluctuations during operation, enabling a wide and adjustable output voltage range according to the temperature differences. A prototype of the 10-kW, 50-kHz PSFB converter, operating with an input voltage range of 700–750 V and output voltage of 77–138 V, was developed and tested both through simulations and experimentally. The converter achieved a maximum efficiency of 97% and demonstrated a high power density of 2.23 kW/L, thereby validating the effectiveness of the proposed design for railway battery charging applications. Full article

Accurate carbon price forecasting is essential for market stability, risk management, and policy-making. To address the nonlinear, non-stationary, and multiscale nature of carbon prices, this paper proposes a forecasting framework integrating secondary decomposition, two-stage feature selection, and dynamic ensemble learning. Firstly, the original price series is decomposed into intrinsic mode functions (IMFs), using complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN). The IMFs are then grouped into low- and high-frequency components based on multiscale entropy (MSE) and K-Means clustering. To further alleviate mode mixing in the high-frequency components, an improved variational mode decomposition (VMD) optimized by particle swarm optimization (PSO) is applied for secondary decomposition. Secondly, a two-stage feature-selection method is employed, in which the partial autocorrelation function (PACF) is used to select relevant lagged features, while the maximal information coefficient (MIC) is applied to identify key variables from both historical and external data. Finally, this paper introduces a dynamic integration module based on sliding windows and sequential least squares programming (SLSQP), which can not only adaptively adjust the weights of four base learners but can also effectively leverage the complementary advantages of each model and track the dynamic trends of carbon prices. The empirical results of the carbon markets in Hubei and Guangdong indicate that the proposed method outperforms the benchmark model in terms of prediction accuracy and robustness, and the method has been tested by Diebold Mariano (DM). The main contributions are the improved feature-extraction process and the innovative use of a sliding window-based SLSQP method for dynamic ensemble weight optimization. Full article