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A solutions-focussed operational model to connect catchment water research to environmental resilience
Get PDFElectronic Hong Ou Mandel interferences to unveil the 2/3 fractional quantum Hall edge channel dynamics
Get PDFElectronic Hong-Ou-Mandel (HOM) current noise interferometry has revealed anyonic statistics in Fractional Quantum Hall (FQH) states at ν = 1/3 and 2/5. However, hole-conjugate phases (½ < ν < 1), like ν = 2/3, host both charge and neutral edge modes, are disorder-sensitive, and pose challenges for interferometry. We present time-domain HOM and Photon-Assisted Shot Noise (PASN) measurements at ν = 2/3 to probe edge mode dynamics and tunneling charge. Using PASN’s fractional Josephson relation, we measure an e/3 tunneling charge and show that DC shot noise overestimates charge below ~100 mK. PASN reveals damping of downstream charge modes due to limited propagation of upstream neutral modes beyond a micrometer-scale equilibration length. Time-resolved HOM measurements confirm picosecond pulse broadening. These results suggest revisiting the neutral mode status, highlight the limitations of HOM interferometry in hole-conjugate phases and provide a path to explore complex FQH states that host neutral or non-Abelian modes
Substrate Contribution to Ultrafast Spin Dynamics in 2D van der Waals Magnets
Get PDFWe propose a model that is able to reproduce the type-II ultrafast demagnetization dynamics observed in 2D magnets. The spin system is coupled to the electronic thermal bath and is treated with atomistic spin dynamics, while the electron and phonon heat baths are described phenomenologically by coupled equations via the two-temperature model. Our proposed two-temperature model takes into account the effect of the heated substrate, which for 2D systems results in a slow demagnetization regime. We applied the framework to a generic 2D system, CrI_{3}, and we are able to observe a type-II demagnetization process characterized by two steps, the first step being attributed to the free electrons generated when the system behaves as a quasimetal under optical excitation, and the second step, the slower demagnetization region, due to the heated substrate. Finally, after laser excitation, we are able to observe domain formation in CrI_{3}, similar to recent experimental observations. Our generalized two-temperature model enhances the modeling of ultrafast magnetization dynamics processes by effectively describing the quasimetallic behavior of certain magnetic materials and the influence of a heated adjacent layer
Editorial: Nanotechnology-based devices and systems for enhanced sensitivity and efficiency in biomedical applications.
Get PDFChannel geometry controls on chemical behavior in rivers: insights from a comparative field study
Get PDFMicrobially mediated transformations, such as nitrification and biodegradation, play a crucial role in removing pollutants from rivers. Although in-stream removal rate coefficients are often assumed to be spatially and temporally constant, they are likely affected by the channel shape and size because these factors control contact between the water column and fixed biofilms. Here, we test the hypothesis that transformation rate constants are inversely proportional to the hydraulic radius (R: ratio of the channel cross-sectional area to wetted perimeter) in dye tracing experiments conducted in two U.K. rivers with contrasting morphologies: (1) the River Maun (shallow: mean bankfull R = 1.25 m) and (2) the River Calder (deep: mean bankfull R = 3 m). In each case, a slug of rhodamine WT was injected upstream of a wastewater outfall, and samples were collected downstream, staggered by the rhodamine travel time. Rate constants were derived for sucralose, ammonium, caffeine, and linear alkylbenzenesulfonate. Sucralose (persistent, hydrophilic, and exclusively of wastewater origin) was used as a conservative tracer to adjust model fits for dilution. Higher rate coefficients were observed for all biotransformed pollutants in the Maun compared to the Calder, supporting the hypothesis and highlighting the need to consider geomorphology in models of chemical behavior
Predicting the heterogeneous chemo-mechano-biological degeneration of cartilage using 3-D biphasic finite elements
Get PDFBackground and Objective:
Osteoarthritis (OA), a debilitating joint disease, involves progressive cartilage degeneration and altered biomechanics. We established a novel chemo-mechano-biological (CMB) modeling framework that integrates biphasic mechanics with biochemical and biological processes to predict cartilage degeneration (i.e. loss of masses of constituents presenting as loss of thickness) under pathological conditions. Our framework captures time-dependent remodeling of cartilage constituents in 3-D driven by mechanical loading, biochemical signaling, and cellular metabolism.
Methods:
We formulated a nonlinear, large-strain biphasic constitutive model coupled with a biochemical model of signaling pathways. Our framework incorporates depth-dependent metabolic activity, explicitly linking availability of oxygen to chondrocyte behavior and extracellular matrix (ECM) remodeling. We included interactions among mechanical stimuli, growth factors, pro-inflammatory cytokines, enzymes (collagenases and aggrecanases), and inhibitors (TIMP). We conducted nonlinear, biphasic finite element (FE) simulations in 3-D, allowing for realistic representations of intra-cartilage heterogeneity. We simulated cyclic, confined compression of full-thickness cartilage, a scenario mimicking conditions in vivo during walking or running.
Results:
Our simulations spanning 24 months presented realistic patterns of cartilage degeneration including zonal variations in matrix composition and thickness loss. In healthy cartilage, interstitial fluid pressure resisted mechanical loading, maintaining ECM integrity. However, in degenerative overloading conditions, enzymatic activity and altered metabolic functions led to increased porosity, reduced fluid pressure, and heterogeneous degradation of ECM. Incorporating depth-dependent metabolic activity revealed pronounced degeneration in the superficial zone (SZ) and progressively reduced loss toward the deep zone (DZ). This outcome aligns with experimental evidence on progression of OA. Oxygen availability played a critical role, with higher levels exacerbating degradation, consistent with findings linking oxidative stress to cartilage degeneration.
Conclusion:
Our nonlinear, biphasic FE framework offers a robust tool for investigating mechanisms of cartilage degeneration and OA, and advancing therapeutic strategies. It uniquely integrates biphasic mechanics, signaling pathways, and metabolic activity in 3-D, providing insights into patterns of cartilage degeneration. We previously developed automated and publicly available tools to generate patient-specific knee models from MR Images, altogether enabling personalized diagnostics/prognostics and pre-/post-operative planning. Our CMB framework is also publicly available as a plugin for FEBio at https://github.uconn.edu/imLab/FEVGnR-Plugin, supporting broader research on OA and cartilage biomechanics
Neuroanatomical normative modelling in frontotemporal lobar degeneration: higher heterogeneity in the behavioural variant
Get PDFIntroduction
Frontotemporal lobar degeneration (FTLD) includes heterogenous diseases: behavioural variant frontotemporal dementia (bvFTD), primary progressive aphasias (PPA), progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). We applied neuroanatomical normative modelling to quantify individual atrophy patterns and heterogeneity within and between FTLD forms.
Methods
We included 160 participants across FTLDNI and 4RTNI studies: controls (n = 15), bvFTD (n = 22), nfvPPA (n = 14), svPPA (n = 21), CBS (n = 43) and PSP (n = 45). Using cortical thickness and subcortical volumes from 3T MRIs, we applied normative modelling with a large healthy reference dataset (n = 58,836), further accounting for age, sex, and scanner. Outlier regions (z < – 1.96) were used to compute total outlier counts (tOC) and Hamming distances, capturing individual atrophy patterns and inter-subject dissimilarity.
Results
bvFTD, svPPA, CBS and PSP showed significantly higher cortical tOC than controls, with all groups showing higher subcortical tOC than controls, especially svPPA and PSP. bvFTD, svPPA, CBS and PSP had significantly higher cortical Hamming distance scores than controls, with higher scores in bvFTD and svPPA than nfvPPA and PSP. svPPA and PSP had significantly higher subcortical scores than controls and CBS. Greater disease severity (measured using the Clinical Dementia Rating—CDR for PSP and CBS, and the CDR® plus NACC-FTLD global scores for FTD variants) was associated with increased tOC and dissimilarity, highlighting the link between clinical progression and neuroanatomical heterogeneity.
Conclusions
The pronounced heterogeneity within and between FTLD subtypes (particularly in bvFTD) increases with disease progression and may reflect distinct underlying pathologies. This supports the development of subtype-specific biomarkers and emphasize the need for personalized diagnostic and therapeutic strategies
Building clusters without trust: Government as a relational architect in industrial cluster formation
Get PDFIndustrial clusters in developing economies often confront a paradox: engineered by state policy yet lacking the pre-trust and shared norms that drive organic networks. Drawing on two industrial clusters in Iran, we unpack how government actors become “relational architects,” scaffolding structural and cognitive dimensions of social capital to seed collaboration where trust is absent. However, our study also warns that heavy-handed, top-down site selections and mandated partner mixes can fracture the nascent bonds they intend to forge. In contrast, well-placed intermediaries and collaboratively crafted capacity-building forums can repair those fractures, allowing genuine trust to emerge—though only after sustained, state-mediated interaction. By questioning the long-held belief that trust must precede collective action, we demonstrate a reversed sequence: structural links and cognitive alignment can give rise to relational capital over time. These insights offer cautionary implications for policy: instead of simply transplanting blueprints, policymakers must blend directive measures with authentic, context-sensitive facilitation if they hope to build resilient, trust-based clusters
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