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Strategy research has long linked sustained competitive advantage to barriers to imitation. We highlight network effects as an alternative mechanism and adopt a geotemporal perspective to theorize how firms sustain advantage as it unfolds over time in international markets. Our study examines this question through the performance persistence of social platforms, focusing on how institutional and demand-side conditions shape the sustainability of platforms’ competitive advantages. We propose that intellectual property rights protection may restrict the degree of freedom in information dissemination, dampening the role of network effects in sustaining superior performance, whilst demand heterogeneity may enhance the value of sizable network membership for information consumption. Evidence from a cross-country dataset of platforms supports these predictions. These findings enrich our understanding of how geographic variations shape the endurance of a platform’s competitive advantage over time, offering implications for both global strategy and platform governance.
Cognitive and behavioral symptoms of major depressive disorder (MDD) are linked to aberrant changes in the controllability of brain networks. However, previous studies examined network controllability using white matter tractography, neglecting the contributions of gray matter. We aimed to examine differences in the controllability of morphometric networks between patients with MDD and demographic-matched healthy controls and identify the associated neurobiological signatures.
Methods
Based on the structural and diffusion MRI data from two independent cohorts, we calculated the controllability of morphometric similarity networks for each participant. A generalized additive model was used to investigate the case–control differences in regional controllability and their cognitive and behavioral associations. We investigated the associations between imaging-derived controllability and neurotransmitters, brain metabolism, and gene transcription profiles using multivariate linear regression and partial least squares regression analyses.
Results
In both cohorts, depression-related abnormalities of morphometric network controllability were primarily located in the prefrontal, cingulate, and visual cortices, contributing to memory, sensation, and perception processes. These abnormalities in network controllability were spatially aligned with the distributions of serotonergic transmission pathways as well as with altered oxygen and glucose metabolism. In addition, these abnormalities spatially overlapped with differentially expressed genes enriched in annotations related to protein catabolism and mitochondria in neuronal cells and were disproportionately located on chromosome 22.
Conclusions
Collectively, neuroimaging evidence revealed aberrant morphometric network controllability underlying MDD-related cognitive and behavioral deficits, and the associated genetic and molecular signatures may help identify the neurobiological mechanisms underlying MDD and provide feasible therapeutic targets.
Menopausal age represents the endpoint of the entire reproductive cycle of women, and it is a biological marker that indicates the overall health and ageing status of women. Flavonoids are the most common polyphenolic compounds in the daily diet, and their intake is related to reduced risks of certain diseases. Our study aimed to analyse the relationships between the intake of flavonoids and menopausal age. We selected 29 940 participants from National Health and Nutrition Examination Survey database from 2007–2008, 2009–2010 to 2017–2018. A total of 680 participants were included in our analysis after screening. Multiple logistic regression was used to explore the association between dietary flavonoid subclasses intake and menopausal delay (≥ 55 years old). Restricted cubic splines plots were generated to reveal the nonlinear relationships between the subclasses of flavonoids intake and menopausal age. According to the adjusted multiple factor logistic regression analysis, the top quartile intake (compared with bottom intake) of anthocyanidins was positively associated with delayed menopause (OR = 4·123; 95 % CI: 1·130, 15·041; Ptrend = 0·036), whereas the moderate intake of flavonols was negatively associated with delayed menopause (Q2 v. Q1, OR = 0·081 (95 % CI: 0·025, 0·261), Ptrend = 0·001; Q3 v. Q1, OR = 0·271 (95 % CI: 0·093, 0·791), Ptrend = 0·023). The restricted cubic splines revealed that non-linear association was observed between the intake of isoflavones, flavan-3-ols, flavonols and later menopause (P value for non-linearity < 0·05). Our findings suggest that specific dietary flavonoids intake may have potential roles in regulating menopausal timing.
This study aimed to determine the optimal Biological Effective Dose (BED)-based compensation strategy for treatment interruptions in left-sided breast cancer radiotherapy, with a focus on evaluating cardiac substructures to address a previously unmet clinical need.
Methods:
Twenty patients with left-sided breast cancer who had received radiotherapy were retrospectively enrolled.
Simulations assumed treatment interruptions (number of interruption days) occurred after the first week, ranging from 1 to 10 days. Three BED-based compensation strategies were evaluated: (A) maintaining total fractions and days while delivering twice-daily treatments; (B) maintaining total days while increasing the dose per fraction; and (C) keeping the dose per fraction constant while extending the overall treatment course. Original uninterrupted plans served as the baseline. BEDs for the planning target volume (PTV), simultaneous integrated boost (SIB), cardiac substructures and other organs at risk (OARs) were calculated. Physical and BED differences among the schemes were systematically compared.
Results:
Compared to the original scheme, physical doses to PTV and SIB were lower in Scheme B but higher in Scheme C. As interruptions increased from 1 to 10 days, PTV and SIB doses in Scheme B decreased to minimum values of 42.71 Gy and 50.58 Gy, respectively, while Scheme C resulted in maximum values of 58.60 Gy and 67.15 Gy. Analysis of BED changes (ΔBED) in OARs revealed that the left anterior descending artery (LAD) was the most affected cardiac substructure, with ΔBED values of 0.41, –1.20 and 0.60 for Schemes A, B and C, respectively, at 10 interruption days. Among other OARs, the left lung showed the highest ΔBED changes (0.39, –0.30 and 0.32, respectively). Most OAR comparisons reached statistical significance (ANOVA, p < 0.05).
Conclusion:
Compensation strategies for radiotherapy interruptions significantly influence the BED of OARs, particularly in the LAD and left lung. Scheme B most effectively reduced the BED of OARs but requires replanning. Schemes A and C offer clinical convenience at the cost of a higher BED of OARs. The choice of compensation strategy should be individualised based on clinical priorities and patient-specific anatomy.
In this paper, we numerically investigate the orbit dynamics of three-dimensional symmetric Janus drops in shear flow using an improved ternary-fluids phase field method, focusing on how drop deformation and initial orientation affect the orbit drift of two configurations of Janus drops: dumbbell-shaped and near-spherical. We find that the motion of dumbbell-shaped drops eventually evolves into tumbling, while near-spherical drops attain stable spinning. We attribute this bifurcation in orbit drift to contrasting deformation dynamics and shape-dependent hydrodynamics of the two configurations. Specifically, the drift bifurcation is closely related to the aspect ratio of Janus drops at equilibrium, giving rise to two distinct mechanisms: (1) coupling between outer interface deformation and the surrounding flow field; and (2) interplay between inner interface deformation and vortices enclosed within the drop. In addition, we observe that for the dumbbell-shaped Janus drops with different aspect ratios, their tumbling dynamics resembles ellipsoids in shear flow. Moreover, the trajectories of the dumbbell-shaped Janus drops during orbit drift collapse onto a universal curve, independent of their initial orientations, and significant deformation and inertia accelerate the orbit transition. To quantitatively evaluate the effect of drop deformation on the orbit drift of the dumbbell-shaped Janus drops, we propose an effective aspect ratio model based on the drop shapes at equilibrium and at the maximum elongation. By incorporating the effective aspect ratio into Jeffery’s theory for solid particles, we accurately predict the rotation period and angular velocity of Janus drops in the tumbling regime and during the orbit drift, especially for drops with linear deformation. Moreover, the orbit parameter $C$ is found to vary exponentially with time for drops with linear deformation, while the time variation of $C$ transits from one exponential function to another for drops with nonlinear deformation.
The electrokinetic and unstable behaviour near strongly polarised surfaces cannot be well captured by the canonical asymptotic theory for induced-charge electro-osmosis, and the intrinsic mechanism remains unclear. Using direct numerical simulations and scaling analysis, this paper reveals that, near the strongly polarised surfaces, the strong electric double layer charging induces a strong local electric field, which drives the cations in the electrical double layer to extend to a finite region and form an extended space-charge (ESC) layer. The ESC triggers flow instability near strongly polarised surfaces, causing a transition of the velocity scaling exponent in the electric field dependence from a 2 to a 4/3 power law. The findings and mechanisms pave the way for designs of energy and biomedical systems.
This paper presents an experimental and analytical investigation of the turbulent transport and flame geometric characteristics of free turbulent buoyant diffusion flames under different fuel mass fluxes and burner boundary conditions (i.e. with/without a flush floor). The stereo particle image velocimetry technique was utilised to measure the three-dimensional instantaneous velocity fields of the free methane buoyant flames with a burner diameter (d) of 0.30 m and dimensionless heat release rates ($\dot{Q}^{*}$) of 0.50–0.90. The results showed that, compared with the configuration without a floor, the time-averaged axial velocity fluctuations squared and the time-averaged radial velocity fluctuations squared decreased, and the peak values of the time-averaged radial velocity, the time-averaged radial velocity fluctuations squared and the time-averaged axial and radial fluctuation product shifted towards the burner centreline in the configuration with a flush floor. Based on the dimensional analysis and the gradient transport assumption, the mean turbulent viscosity within the mean flame height ($\nu _{t}^{=}$) was scaled. Compared with the configuration without a floor of under equal $\dot{Q}^{*}$, the turbulent viscosity decreased in the configuration with a flush floor, resulting in an increase in mean flame height and a reduction in mean flame width. Based on the concepts of turbulent mixing and equal axial convection and radial diffusion times, semi-physical models were derived for the mean flame height and the mean flame width, respectively. The two correlations agreed well with the experimental data of this work for the two burner configurations with and without a flush floor.
The treatment response for the negative symptoms of schizophrenia is not ideal, and the efficacy of antidepressant treatment remains a matter of considerable controversy. This systematic review and meta-analysis aimed to assess the efficacy of adjunctive antidepressant treatment for negative symptoms of schizophrenia under strict inclusion criteria.
Methods
A systematic literature search (PubMed/Web of Science) was conducted to identify randomized, double-blind, effect-focused trials comparing adjuvant antidepressants with placebo for the treatment of negative symptoms of schizophrenia from database establishment to April 16, 2025. Negative symptoms were examined as the primary outcome. Data were extracted from published research reports, and the overall effect size was calculated using standardized mean differences (SMD).
Results
A total of 15 articles, involving 655 patients, were included in this review. Mirtazapine (N = 2, n = 48, SMD −1.73, CI −2.60, −0.87) and duloxetine (N = 1, n = 64, SMD −1.19, CI −2.17, −0.21) showed significantly better efficacy for negative symptoms compared to placebo. In direct comparisons between antidepressants, mirtazapine showed significant differences compared to reboxetine, escitalopram, and bupropion, but there were no significant differences between other antidepressants or between antidepressants and placebo. No publication bias for the prevalence of this condition was observed.
Conclusions
These findings suggest that adjunctive use of mirtazapine and duloxetine can effectively improve the negative symptoms of schizophrenia in patients who are stably receiving antipsychotic treatment. Therefore, incorporating antidepressants into future treatment plans for negative symptoms of schizophrenia is a promising strategy that warrants further exploration.
Major depressive disorder (MDD) patients exhibit a mood-congruent emotional processing bias within the amygdala toward negative facial stimuli at both unconscious and conscious levels. Therefore, our study aimed to investigate the temporal and spatial dynamics of amygdala along with its interactions with the whole brain during implicit and explicit conditions in MDD.
Methods
Thirty MDD patients and 26 healthy controls (HCs) underwent magnetoencephalography (MEG) recordings and performed implicit and explicit emotional face recognition tasks with happy, sad, and neutral facial expressions. Using the amygdala as a seed region, time frequency representations (TFR) and functional connectivity (FC) were calculated. Pearson correlation analyses measured the relationship between TFR and FC values with clinical symptoms.
Results
During implicit processing, MDD patients exhibited left amygdala activation in the gamma power (60–70 Hz) before 250 ms in response to sad facial stimuli compared to HCs. In the implicit mode, there were increased FC between the right amygdala and several brain regions in the occipitoparietal lobes, as well as higher FC between the left amygdala and putamen in MDD patients. Additionally, the right amygdala was positively correlated with the severity of depression and anxiety during implicit processing.
Conclusions
MDD patients had lateralized amygdala activation in response to sad facial expressions during unconscious emotional recognition of facial stimuli. Our study provided valuable insights into the spatiotemporal dynamics of facial emotional recognition associated with depressive and anxiety-related cognitive bias during implicit and explicit processing.
The COVID-19 pandemic exacerbated psychological distress, but limited information is available on the shifts in mental health symptoms and their associated factors across different stages. This study was conducted to more reliably estimate shifts in mental health impacts and to identify factors associated with symptoms at different pandemic stages.
Methods
We performed a national repeated cross-sectional study at stable (2021), recurrence (2022), and end-of-emergency (2023) stages based on representative general national population with extensive geographic coverage. Anxiety, depression, post-traumatic stress disorder (PTSD) and insomnia symptoms were evaluated by GAD-7, PHQ-9, IES-R and ISI scales, respectively, and their associated factors were identified via multivariable linear regression.
Results
Generally, 42,000 individuals were recruited, and 36,218, 36,097 and 36,306 eligible participants were included at each stage. The prevalence of anxiety, depression and insomnia symptoms increased from 13.7–16.4% at stable to 17.3–22.2% at recurrence and decreased to 14.5–18.6% at end of emergency, while PTSD symptom continuously increased from 5.1% to 7.6% and 9.2%, respectively (all significant, P < 0.001). Common factors associated with mental health symptoms across all stages included centralized quarantine, frontline work and residence in initially widely infected areas. Centralized quarantine was linked to anxiety, depression, PTSD and insomnia during the stable, recurrence and end-of-emergency stages. Frontline workers exhibited higher risks of anxiety, depression and insomnia throughout these stages. Individuals in initially widely infected areas were more likely to experience depression and PTSD, particularly during the stable and recurrence stages. Stage-specific risk factors were also identified. Lack of outdoor activity was associated with anxiety, depression and insomnia during the stable and recurrence stages. Residents in high-risk areas during the recurrence stage correlated with increased anxiety and insomnia. Suspected infection was tied to anxiety and insomnia in the recurrence and end-of-emergency stages, while the death of family or friends was linked to PTSD during recurrence and to depression, PTSD and insomnia at the end-of-emergency stage.
Conclusions
Mental health symptoms increased when pandemic recurred, and could remain after end-of-emergency, requiring prolonged interventions. Several key factors associated with mental symptoms and their variations were identified at different pandemic stages, suggesting different at-risk populations.
Schizophrenia progresses through high-risk, first-episode, and chronic stages, each associated with altered spontaneous brain activity. Resting state functional MRI studies highlight these changes, but inconsistencies persist, and the genetic basis remains unclear.
Methods
A neuroimaging meta-analysis was conducted to assess spontaneous brain activity alterations in each schizophrenia stage. The largest available genome-wide association study (GWAS) summary statistics for schizophrenia (N = 53,386 cases, 77,258 controls) were used, followed by Hi-C-coupled multimarker analysis of genomic annotation (H-MAGMA) to identify schizophrenia-associated genes. Transcriptome-neuroimaging association and gene prioritization analyses were performed to identify genes consistently linked to brain activity alterations. Biological relevance was explored by functional enrichment.
Results
Fifty-two studies met the inclusion criteria, covering the high-risk (Nhigh-risk = 409, Ncontrol = 475), first-episode (Ncase = 1842, Ncontrol = 1735), and chronic (Ncase = 1242, Ncontrol = 1300) stages. High-risk stage showed reduced brain activity in the right median cingulate and paracingulate gyri. First-episode stage revealed increased activity in the right putamen and decreased activity in the left gyrus rectus and right postcentral gyrus. Chronic stage showed heightened activity in the right inferior frontal gyrus and reduced activity in the superior occipital gyrus and right postcentral gyrus. Across all stages, 199 genes were consistently linked to brain activity changes, involved in biological processes such as nervous system development, synaptic transmission, and synaptic plasticity.
Conclusions
Brain activity alterations across schizophrenia stages and genes consistently associated with these changes highlight their potential as universal biomarkers and therapeutic targets for schizophrenia.
Based on the characteristics of the variable pivot gait during the human load-carrying, this paper proposes a double-leg coordination assistance principle for load-carrying: assisting support of the guiding leg at the heel-pivot stage by the spring to reduce the collision, which can reduce the ankle moment of the following leg that is performing the push-off at the toe-pivot stage. A novel unpowered load-carrying exoskeleton (ULE) with a double-support closed-chain configuration is designed, and the theoretical verification is carried out. Five subjects participate in the load-carrying and metabolic cost experiments for assisting and energy-saving effect evaluation, and the angle and moment of human joints, plantar pressure, spring compression and human net metabolic rate are analyzed. Compared with carrying load by the human alone, wearing the novel ULE with spring reduces the human peak ankle moment performing the push-off by up to 11.9 ± 1.6% (Mean±SE, 10 kg), average ankle moment over the support phase by up to 36.8 ± 9.1% (Mean±SE, 5 kg) and the average vertical plantar pressure by up to 8.1 ± 1%% (Mean±SE, 15 kg). Meanwhile, wearing the novel ULE reduces the human net metabolic rate by 5.6 ± 0.5% (Mean±SE, 10 kg), 4.1 ± 0.7% (Mean±SE, 15 kg) and 5.9 ± 1.6% (Mean±SE, 20 kg). The results show that the novel ULE can provide support and joint moment assistance over the whole support phase while reducing human net metabolic rate. This study can also be applied to the powered load-carrying exoskeleton, providing a new avenue.
Antimicrobial resistance (AMR) is a global health crisis exacerbated by policies like China’s Volume-Based Procurement (VBP), which may inadvertently increase antimicrobial overuse. This study evaluates a clinical pharmacist-led Antimicrobial Stewardship (AMS) program with prospective audit for special-restricted antimicrobials under VBP.
Methods:
A retrospective quasi-experimental interrupted time-series analysis compared pre-intervention (2022) and post-intervention (2023–2024) data at Tongji Hospital, a tertiary hospital in Wuhan, China. Key metrics included Antimicrobial Use Density (AUD), prescription rationality, antimicrobial costs, and multidrug-resistant infection rates.
Results:
The intervention significantly improved prescription appropriateness for special-restricted antimicrobials (80.24% vs. 93.83%, P < 0.005) and reduced AUD (47.87 vs. 34.25, P < 0.001). Total antimicrobial costs decreased by 41.26%, with a reduction in the incidence of multidrug-resistant infections from 0.084% to 0.062% (P < 0.05). Carbapenem use correlated with CRKP isolation rates (R = 0.62, P < 0.05). Clinical pharmacists rejected 10.24% of prescriptions, all accepted by physicians.
Conclusion:
Pharmacist-led prospective audits optimize antimicrobial use under VBP, mitigate resistance risks, and reduce costs, while acknowledging that concurrent infection control measures may have contributed to these trends. This model may inform similar interventions in other institutions, particularly those in resource-limited settings.
To investigate multiple effects of the interaction between V. cholerae and phage on cholera transmission, we propose a degenerate reaction-diffusion model with different dispersal rates, which incorporates a short-lived hyperinfectious (HI vibrios) state of V. cholerae and lower-infectious (LI vibrios) state of V. cholerae. Our main purpose is to investigate the existence and stability analysis of multi-class boundary steady states, which is much more complicated and challenging than the case when the boundary steady state is unique. In a spatially heterogeneous case, the basic reproduction number $\mathscr{R}_{0}$ is defined as the spectral radius of the sum of two linear operators associated with HI vibrios infection and LI vibrios infection. If $\mathscr{R}_{0}\leq 1$, the disease-free steady state is globally asymptotically stable. If $\mathscr{R}_{0}\gt 1$, the uniform persistence of phage-free model, as well as the existence of the phage-free steady state, are established. In a spatially homogeneous case, when $\ \;\widetilde{\!\!\!\mathscr{R}}_{0}\gt 1$, the global asymptotic stability of phage-free steady state and the uniform persistence of the phage-present model are discussed under some additional conditions. The mathematical approach here has wide applications in degenerate Partial Differential Equations.
The population-based structural health monitoring paradigm has recently emerged as a promising approach to enhance data-driven assessment of engineering structures by facilitating transfer learning between structures with some degree of similarity. In this work, we apply this concept to the automated modal identification of structural systems. We introduce a graph neural network (GNN)-based deep learning scheme to identify modal properties, including natural frequencies, damping ratios, and mode shapes of engineering structures based on the power spectral density of spatially sparse vibration measurements. Systematic numerical experiments are conducted to evaluate the proposed model, employing two distinct truss populations that possess similar topological characteristics but varying geometric (size and shape) and material (stiffness) properties. The results demonstrate that, once trained, the proposed GNN-based model can identify modal properties of unseen structures within the same structural population with good efficiency and acceptable accuracy, even in the presence of measurement noise and sparse measurement locations. The GNN-based model exhibits advantages over the classic frequency domain decomposition method in terms of identification speed, as well as against an alternate multilayer perceptron architecture in terms of identification accuracy, rendering this a promising tool for PBSHM purposes.
An experimental study of the equation of state for metallic powders under impact loading was carried out at a high-energy laser facility. A laser-ablatable micro-target was obtained to satisfy the laser equation of state for experimental study, and the precise characterization of the initial density was realized. The technique boosts the pressure of copper powder to 1400 GPa. The data consistency can effectively distinguish the data trends under different initial densities (~4.05 and 4.50 g/cm3). Experimental data can effectively distinguish the differences between the high-pressure Thomas–Fermi model and the Thomas–Fermi–Kirzhnits model, providing strong support for the WEOS-Pα model of the Institute of Applied Physics and Computational Mathematics, which is more in line with the actual state description of the material. This experimental technique can be extended to study the high-pressure physical properties of other powder particles.
We strengthen the maximal ergodic theorem for actions of groups of polynomial growth to a form involving jump quantity, which is the sharpest result among the family of variational or maximal ergodic theorems. As two applications, we first obtain the upcrossing inequalities with exponential decay of ergodic averages and then provide an explicit bound on the convergence rate such that the ergodic averages with strongly continuous regular group actions are metastable (or locally stable) on a large interval. Before exploiting the transference techniques, we actually obtain a stronger result—the jump estimates on a metric space with a measure not necessarily doubling. The ideas or techniques involve martingale theory, non-doubling Calderón–Zygmund theory, almost orthogonality argument, and some delicate geometric argument involving the balls and the cubes on a group equipped with a not necessarily doubling measure.