Search Results (807)

Virtual Coupling (VC) is an emerging railway signalling concept that allows successive trains to run closer together than the conventional absolute braking distance, promising higher line capacity. Prior VC research has mainly targeted controller design under a relative-braking assumption, leaving a gap in holistically defining and simulating VC scenarios across absolute and relative braking, and across inter-consist (train-to-train) and intra-consist (single-train splitting) configurations. This study addresses that gap by developing a longitudinal train dynamics model, deriving minimum-separation formulations for absolute and relative braking with a proposed dynamic safety margin, and designing a Model Predictive Control (MPC) train-following controller. Four operational scenarios, covering coupling and uncoupling at standstill and in motion, were simulated for a nine-car Class 390/0 Pendolino on the West Coast Main Line in the United Kingdom, between Rugby and Birmingham International. Relative-braking VC on a plain track reaches up to 240 trains per hour at a maximum headway of 15 s, whereas junction-constrained scenarios are capped at 60 trains per hour by the assumed switch-processing time, irrespective of braking principle. Absolute-braking VC achieves 60–70 trains per hour across scenarios. Splitting one train into a seven-car through-service and a two-car stopping portion reduced the through-service journey time by 27% and the combined energy consumption by 21.4% relative to an unsplit nine-car service. Full article

Physics-based models are useful for the analysis and optimization of crystalline-silicon solar cells when many device designs must be evaluated. This paper presents a compact transfer-matrix framework for one-dimensional carrier transport and physics-constrained optimization in bifacial $p^{+}$–n–$n^{+}$ crystalline-silicon solar cells under front-side illumination. The model includes a distributed optical generation profile, explicit emitter, base, and rear-field regions, surface recombination, doping-dependent mobility, Auger recombination, band-gap narrowing, sheet and contact resistances, and external series and shunt losses. The front and rear dopant distributions are described by complementary-error-function profiles, so their junction depths follow from the diffusion parameters and base concentration instead of being independent optimization variables. The solver is verified in limiting transport conditions and with tabulated generation data. The complete model is then calibrated against the reported photovoltaic figures of merit of an experimental bifacial n-type passivated-emitter and rear-totally-diffused (n-PERT) solar cell, which serves as the reference device and is subsequently applied to global optimization. The calibration reproduces a short-circuit current density of $J_{sc}=39.20\mathrm{mA}/{\mathrm{cm}}^2$, an open-circuit voltage of $V_{oc}=653.1\mathrm{mV}$, a fill factor of 0.783, and an efficiency of 20.05%. For the 180 µm reference geometry, the optimized design reaches an efficiency of 20.63%. Independent optimizations for wafer thicknesses of 160, 180, and 200 µm produce a consistent family of solutions with efficiency gains of approximately 0.56–0.60 percentage points. These gains result from the higher open-circuit voltage and fill factor despite a moderate reduction in short-circuit current density, while the optimized total series resistance remains nearly constant. The framework provides a physically interpretable method for combining carrier-transport modeling, experimental calibration, inverse design, and repeated global optimization. Full article

The interaction of chemicals, nanoparticles, and circulating cells with the endothelium depends on the magnitude of the mechanical shear produced by the flow of blood. When simulating those interactions with microphysiological systems (MPSs), it is critical to reproduce those shear conditions faithfully. For example, unidirectional flow of a specific magnitude keeps the endothelium healthy with normal barrier tissue function, while bidirectional flow mimics disease conditions with compromised barrier function. Additionally, in MPS, recirculating fluid may be necessary to retain tissue-derived factors and metabolites. However, existing MPS designs struggle to achieve medium recirculation of small volumes of liquid with precise flow control. Here, we present an MPS design that is highly versatile and overcomes this limitation. We demonstrate how the device can produce a wide range of fluidic flow rates that can accommodate both low shear conditions suitable for tissues that typically are only exposed to interstitial flow and high shear conditions suitable for barrier tissues that experience blood flow. We demonstrate the device’s functionality by culturing human umbilical vein endothelial cells (HUVEC) and confirming their flow-aligned morphology through immunostaining of the adherens junction protein (VE-cadherin) and actin filaments. Furthermore, we present a mathematical model that can be used to calculate operating parameters for culturing any tissue under optimum conditions. We also discuss how the device can be adjusted to recirculate liquid volumes ranging from 100 µL to 5 mL. This versatile system holds promise for commercial applications, including the investigation of expensive compounds that are limited to very small volume samples such as rare cells (e.g., circulating tumor cells) or engineered therapeutic cells with barrier tissues. By offering precise control over a wide range of flow conditions with medium recirculation of small liquid volumes, our device addresses a critical gap in current MPS technology. Full article

Astrocytes are extensively interconnected via gap junction channels formed primarily by connexin 43 (Cx43) and connexin 30 (Cx30), two proteins that play central roles in intercellular signaling and homeostatic regulation in the brain. Although the functional properties of these connexins have been widely investigated, their spatial organization within astrocytes and its evolution during postnatal development remain poorly characterized. Here, we combined confocal and stimulated emission depletion (STED) super-resolution microscopy to examine the expression, distribution and colocalization of Cx43 and Cx30 immunoreactive puncta in hippocampal astrocytes from postnatal day 15 to adulthood. Quantitative analyses revealed a progressive increase in the number of both Cx43 and Cx30 puncta during development, whereas puncta size remained largely unchanged. Although connexin puncta appeared more distally distributed in mature astrocytes, this shift was fully accounted for by the growth of astrocytes during development. In addition, colocalization between Cx43 and Cx30 increased during maturation, reaching a stable level after postnatal day 30. Finally, STED super-resolution imaging revealed a diversity of connexin arrangements, including isolated puncta as well as complex assemblies composed of multiple neighboring connexin clusters. Together, these findings provide a quantitative characterization of the developmental remodeling of astroglial connexins and identify structural features that may contribute to the maturation of astrocytic networks. Full article

Vision-based hand gesture recognition (HGR) systems are predominantly developed for frontal camera viewpoints, whereas smart-home cameras are often ceiling-mounted, creating a viewpoint-induced domain gap. To investigate this issue, we collected and manually annotated CeilGest, an 18-class ceiling-view hand gesture dataset comprising 156,282 annotated frames from 68 participants recorded in distinct domestic environments. We then systematically evaluated frontal-to-ceiling transfer using YOLO-based detectors trained on HaGRID and compared their performance with an in-domain CeilGest-trained model. On identical ceiling-view footage, the frontal-trained YOLOv8n produced approximately 24× more class-to-class misclassified frames than the in-domain model (486 vs. 20 across 27,000 frames); this large paired difference remained evident when temporal dependence within gesture holds was taken into account. The effect was strongly class-dependent, with AP decreasing by up to 5.5 percentage points for the worst-affected gesture, while the aggregate same-architecture mAP50 difference was 0.6 percentage points. Across five YOLOv8 variants evaluated on frontal HaGRID, mAP50 remained at 0.995, supporting selection of the lightweight YOLOv8n for edge deployment. The complete ceiling-view HGR pipeline was implemented on Raspberry Pi 5 using NCNN and Jetson Orin Nano using TensorRT. Mean inference latency was 74.69 ± 4.72 ms and 12.72 ± 0.12 ms, respectively. During a 10 min continuous Raspberry Pi 5 test, mean inference latency increased by 17.6% and junction temperature reached 90.8 °C with thermal throttling. Power consumption and INT8 inference were not evaluated. Overall, the results show that training–deployment viewpoint consistency is a major consideration for ceiling-mounted HGR and establish an in-domain supervised baseline relative to frontal-only training without domain adaptation. Full article

Gap junctions (GJs) are channels that enable exchange of ions and small molecules between cells, and have been implicated in the development and maintenance of neuropathic pain. Injury-induced glial activation in sensory ganglia is associated with increased coupling by GJs, which in turn enhances neuronal excitability, contributing to pain signaling. Tonabersat (TON) was suggested to act as a GJ blocker with analgesic actions, but these claims have been disputed. Here we examined whether TON blocks GJs and whether it influences pain behavior in a mouse pain model. Gap junctional coupling was assayed by the dye coupling method in mouse liver and trigeminal ganglia. Pain behavior was tested in a mouse model of chemotherapy-induced pain, using von Frey filaments (tactile sensitivity), the acetone method (cold sensitivity) and hot plate (heat sensitivity). Intracellular dye injection showed that TON and the GJ blocker carbenoxolone (both 50 µM) inhibited gap junctional coupling by 70% and 82%, respectively. In the trigeminal ganglia, TON and carbenoxolone inhibited gap junctional coupling by 74 and 77%, respectively. TON selectively reduced heat and cold hypersensitivity, but not mechanical threshold. Carbenoxolone reduced all hypersensitivity types. No sex differences were observed. We conclude that both TON and carbenoxolone reduced coupling, indicating their potential to influence GJ-mediated coupling. In behavioral tests TON showed a selective effect for thermal hypersensitivity, but the underlying mechanism is unclear. Carbenoxolone produced a somewhat greater reduction in coupling compared with TON. These findings suggest that GJs play a role in pain pathways and highlight the need to explore whether other pain-relieving drugs act by blocking GJs. Full article

The maternal–fetal interface functions as an integrated physiological unit whose homeostatic balance determines pregnancy success. Large-pore channels, composed of connexins (Cxs), pannexins (Panxs), calcium homeostasis modulators (CALHMs) and leucine-rich repeat-containing 8 (LRRC8) proteins, mediate direct intercellular communication, autocrine and paracrine release of ATP and other signaling molecules, and scaffold-based signal integration across this interface. In this review, we synthesize current knowledge on large-pore channel expression and their physiological and pathophysiological roles at the maternal–fetal interface, applying an explicit evidence-classification framework to distinguish established functions from emerging findings. We first map the large-pore channel repertoire of each cellular compartment—syncytiotrophoblast, cytotrophoblast, extravillous trophoblast, villous endothelium and decidual stroma—revealing that each compartment expresses a distinct combination of family members, with varying levels of evidence and gestational stage-dependent dynamics. We then analyze the three principal modes of large-pore channel operation in placental physiology: gap-junctional communication driving syncytialization, channel-mediated ATP release enabling paracrine purinergic signaling, and channel-independent scaffolding functions that integrate mechanical and biochemical signals. Next, we examine how each channel family becomes dysregulated in placental-related diseases. We conclude by outlining a targeted research roadmap with clear priorities: the most urgent need is protein-level validation of CALHM and LRRC8 expression in primary trophoblasts, followed by elucidation of gating mechanisms and testing for crosstalk among channel families. By providing both conceptual synthesis and practical guidance, this review aims to accelerate mechanistic understanding and therapeutic development targeting large-pore channels for pregnancy complications that currently lack mechanism-based treatments. Full article

Neuroinflammation within the tumor microenvironment (TME) of central nervous system (CNS) neoplasms, particularly glioblastoma (GBM), is no longer viewed merely as a reactive phenomenon but rather as a major driver of gliomagenesis and malignant transformation. This process involves a shift from acute immune activation to a chronic, sterile state that reshapes the CNS borders and immune niches to favor tumor evasion. This narrative review provides a comprehensive mechanistically focused analysis of the mechanisms governing the inflammatory stroma in primary and metastatic brain neoplasms. It critically examines the ontogeny and transcriptomic profile of myeloid and glial populations, dismantling the binary M1/M2 polarization model in favor of a continuum of functional states determined by metabolic and oxygenation gradients. It also analyzes intracellular signaling cascades, the subversion of innate immunity sensors such as the cGAS-STING pathway, the epigenetic reprogramming of stromal cells, and the role of extracellular vesicles. The electrochemical integration of tumor cells into neuronal circuits via glutamatergic synapses and connexin 43 gap junction coupling is addressed in detail, defining the mitogenic impact of neuronal activity on the tumor. The inflammatory profiles of IDH-wildtype and IDH-mutant gliomas and of secondary brain metastases are contrasted. Finally, the correlates of functional neuroimaging, liquid biopsies, and resistance mechanisms to conventional therapies are analyzed, including the GIANT and SENIPERA clinical trials, CARv3-TEAM-E bivalent cellular immunotherapy preconditioned with the LDC + R regimen, and the accelerated approval of dordaviprone (Modeyso) in H3 K27M-mutant diffuse midline gliomas. Full article

The electrification of transportation pushes traction inverters, on-board chargers, and aircraft propulsion systems toward higher power density, increasingly enabled by wide-bandgap devices, thereby concentrating ever-larger heat fluxes on power semiconductor dies as package-level cooling nears its sustainable limit. Junction temperature is the resulting bottleneck: it caps the usable rating and, through the thermal cycling that fatigues module interconnects, governs reliability and service life. Managing junction temperature therefore requires a coupled chain of processes spanning the device loss that generates the heat, the models that predict it, the parameters which these models require as input, the cooling that removes it, and the control that bounds its excursion. This review traces heat transfer along this chain, organizing each link by method class and comparing representative methods against the limitation that marks its open problem. The methods within each link are relatively mature, whereas the couplings between links and their validation against realistic missions are not. The cross-cutting gaps, among them sparse drive-cycle validation, weak coupling between electro-thermal and aging models, and the absent co-design of cooling and control, are consolidated into a forward research agenda. Full article

Variations and unstable characteristics of two-phase flow in oil and gas pipelines readily induce severe equipment vibration and internal liquid sloshing, which seriously endanger the safety of pipeline systems. Existing investigations on conventional T-junctions have been restricted to single working conditions, without systematic optimization of structural parameters across multiple flow regimes or full evaluation of integrated separation and slug suppression performance. To address this research gap, this work proposed an optimized four-branch T-junction. The geometric configuration of the T-junction was optimized, and a test prototype was fabricated for gas–liquid two-phase flow experiments. Combined with experimental measurements and computational fluid dynamics (CFD) simulations, the overall performance of the optimized T-junction was comprehensively analyzed under diverse flow patterns and operating conditions. The test results indicated that the gas separation efficiency exceeded 90% under stratified flow, whereas slug flow brought strongly time-dependent separation performance. The gas separation efficiency was maintained above 40% for all test cases. The optimized structure reduced liquid slug velocity and length and significantly suppressed liquid level fluctuations in the downstream separation tank. The numerical predictions agreed well with experimental data, which validated the reliability of the present numerical framework. This study provides technical references for the design of inline pipe separators that realize both gas–liquid separation and slug mitigation. Full article

Organic–inorganic hybrid perovskites (OHPs) deliver certified single-junction power conversion efficiencies (PCEs) of up to 27.3% and National Laboratory of the Rockies (NLR)-certified perovskite–silicon tandem values of 34.85%, yet a substantial gap with the Shockley–Queisser (S–Q) limit persists. Grain-boundary (GB) defects are one principal contributor to this gap, driving non-radiative recombination, ion migration, and degradation alongside bulk, interfacial, contact-related, phase-related, and environmental loss channels. Rational passivation demands a non-contact tool capable of identifying and quantifying specific defect species in device-relevant thin films, a capability that conventional probes deliver only in part. This overview assesses the extent to which terahertz time-domain spectroscopy (THz-TDS, 0.2–2.5 THz) fulfills this role. Across five OHP compositions—MAPbI₃, MAPbBr₃, FAPbI₃, and FAPb(Br,I)₃ fabricated by sequential vacuum evaporation (SVE), together with solution-processed γ-CsPbI₃—the THz spectral window captures both intrinsic phonon modes and GB-localized molecular defect vibrations, enabling species-resolved characterization at room temperature. Notably, the oscillator strength of the SVE-specific 1.58 THz absorption in MAPbI₃ scales linearly with XPS-quantified CH₃NH₂ defect concentration, establishing a calibrated, contact-free proxy for defect concentration rather than an absolute defect count; the observable is the defect-induced perturbation of the Pb–X lattice, not the defect population itself. Building on these findings, we propose a three-pillar framework for THz-guided defect engineering: (I) quantitative defect measurement via oscillator-strength analysis, (II) material-specific fingerprint identification from a systematically constructed THz library, and (III) fingerprint-guided defect elimination with real-time feedback—together defining a closed-loop quality-control cycle that connects spectroscopic diagnosis to passivation strategy and, ultimately, to enhanced solar cell efficiency. Throughout, we distinguish capabilities demonstrated to date from extensions that remain proposals, and we define the measurement requirements needed before the framework can be transferred to inline manufacturing control. Full article

Rapid urbanization in metropolitan cities has intensified traffic congestion on major arterial corridors, particularly in mixed-use environments where growing travel demand, limited road capacity, and inadequate infrastructure reduce operational efficiency and increase pedestrian and vehicle conflicts. This study evaluates the operational performance of the Jogeshwari-Vikhroli Link Road (JVLR) in Powai, Mumbai, India, a key urban corridor connecting residential, commercial, and institutional zones to the suburban railway network. The lack of automated Intelligent Transport Systems (ITS) necessitated reliance on manual field surveys and provided an opportunity to develop a practical framework for data-scarce environments. The methodology integrates spatial mapping of regional transit gaps, road inventory surveys, classified traffic volume counts, Passenger Car Unit (PCU) conversions, and Level of Service (LOS) assessments to identify constraints at vehicle-stressed links. The road inventory identified a systemic lack of non-motorized transport (NMT) infrastructure, with dedicated bicycle lanes and adequate road shoulders absent across all surveyed stretches. Although basic pedestrian pathways ranging from 2.0 to 2.5 m in width exist, informal vendors and unregulated on-street parking reduce their operational effectiveness and the effective carriageway width. Broken footpaths, absent or faded lane markings and zebra crossings, and inadequate street hardware and furniture further force pedestrians onto the active carriageway, intensifying mid-block friction and pedestrian and vehicle conflicts. Traffic density was calculated using official speed limits mandated and actively enforced by the Mumbai traffic police as the operational baseline for density-based LOS classification. Density analysis classified 8 of 18 road stretches below LOS C, compared with 3 under traffic-volume-based classification. The paired difference was suggestive but not statistically significant at the 5% level (exact McNemar p = 0.0625), while weighted agreement between the two ordinal LOS classifications was moderate. Seven-day coefficient of variation values ranged from 7.7% to 10.7%, with all 18 stretches below 15%, indicating low to acceptable short-term variability. The most critical congestion occurred along the IIT Bombay Main Gate Road, with a peak traffic flow of 2307 PCU/hour/lane corresponding to LOS E. The study proposes context-sensitive, data-driven interventions to reinforce proposed geometric road widenings, including right-of-way recovery through relocation of unregulated parking and street vendors at high-density nodes such as roads passing through Gandhinagar Junction (22.05 PCU/km/lane), physical dividers and additional merging lanes at Saki Vihar Road, off-carriageway Intermediate Public Transport (IPT) staging bays, grade-separated pedestrian crossings, and localized stormwater drainage improvements beneath Metro Line-6 pillars. Full article

In vitro neurovascular unit (NVU) models are essential for reproducing blood–brain barrier (BBB) transport and neurovascular cell interactions. However, the literature remains fragmented: biomaterial chemistry, fabrication parameters and organ-on-a-chip architecture are commonly evaluated in isolation, while inconsistent reporting of matrix properties, processing history, cell source, flow and barrier readouts prevents head-to-head comparison and the extraction of transferable design rules. To address this gap, this review integrates biomaterials, manufacturing technologies and organ-on-a-chip engineering within a unified material–process–structure–function framework. We translate endothelial junctions, basement-membrane components and perivascular cells into experimentally actionable material requirements; compare natural, synthetic, semisynthetic and decellularized extracellular-matrix hydrogels; and examine crosslinking, peptide functionalization, stimuli responsiveness, composite-network formation and preparation methods. Findings from Transwell, microfluidic, tubular, self-assembled and 3D-bioprinted BBB systems are used to relate matrix stiffness, degradability, ligand density, permeability, device-body material and fabrication route to barrier maturation, analytical access and reproducibility. By defining matched controls and minimum reporting requirements for chemistry, mechanics, transport and processing, this review provides a practical basis for next-generation BBB models that can improve permeability and efficacy screening in drug discovery, reproduce disease- and patient-specific barrier dysfunction, and support individualized response testing with iPSC- or patient-derived cells. Full article

The development of efficient photocatalysts for hydrogen production is a key challenge for sustainable energy technologies. In this study, strontium titanate (SrTiO₃) was synthesized via a citrate-assisted sol-gel method and subsequently modified by deposition-precipitation using nominal HAuCl₄ precursor concentrations of 1.0, 1.5, and 2.0 mM. The resulting materials were characterized by XRD, Raman spectroscopy, UV-Vis diffuse reflectance spectroscopy, SEM with EDS, and X-ray fluorescence (XRF). Au incorporation did not produce detectable changes in the SrTiO₃ crystalline phase or its optical band gap, which remained at 3.19–3.20 eV. The additional absorption band centered near 550 nm was consistent with the localized surface plasmon resonance of metallic Au nanoparticles. Microscopy indicated increasing surface coverage and aggregation at the highest nominal precursor concentration. Under irradiation with a low-pressure Hg lamp, all Au-containing materials presented substantially greater H₂ evolution than pristine SrTiO₃, whereas the comparatively small differences among the Au-modified samples indicated an apparent activity plateau across the evaluated concentration range. Because the Au-associated absorption band near 550 nm lies outside the main 254 nm emission of the lamp and the SrTiO₃ band gap remained mostly unchanged, the enhanced H₂ evolution is consistent with improved interfacial charge separation in the Au/SrTiO₃ system. A Schottky-junction-mediated pathway is proposed based on the observed activity trends and the electronic properties reported for Au/SrTiO₃ interfaces, rather than to a plasmonic or band-gap-tuning effect. The selected STO/Au 2.0 mM material retained approximately 97% of its initial apparent H₂ evolution rate after three consecutive cycles, indicating favorable short-term activity retention. Overall, this comparatively simple synthesis route provides a practical baseline for investigating the influence of nominal Au precursor concentration on H₂ evolution over SrTiO₃. Full article

Portunus trituberculatus is an economically important marine crab species in China. Short-term nutritional conditioning during the juvenile stage may improve their physiological readiness before release. This study compared the effects of four dietary treatments on the growth, antioxidant capacity, immune function, and hepatopancreatic transcriptome of juvenile P. trituberculatus. A 4-week feeding trial compared a commercial pelleted diet (Treatment C) with three natural marine diets: Larimichthys crocea (Treatment Y), Litopenaeus vannamei (Treatment X), and Ruditapes philippinarum (Treatment B). The results demonstrated that Treatments X and B exhibited optimal growth performance, with significantly higher weight gain rate (WGR) and specific growth rate (SGR) than Treatments Y and C (p < 0.05). Regarding immune and antioxidant functions, Treatment X showed significantly enhanced parameters, including total antioxidant capacity (T-AOC) and activities of superoxide dismutase (SOD) and catalase (CAT), as well as contents of reduced glutathione (GSH) and lysozyme (LZM), all of which were markedly higher than those in Treatment C (p < 0.05). Transcriptomic analysis further revealed the molecular mechanisms underlying these physiological enhancements. Compared to the control, Treatment X exhibited significant enrichment in immune-related pathways, specifically the phagosome and gap junction signaling pathways. Notably, key cytoskeleton-related genes (tubulin alpha chain and tubulin beta chain) were significantly up-regulated, suggesting that the shrimp diet enhances cellular immunity by promoting cytoskeletal remodeling and phagocytosis efficiency. In contrast, Treatment B mainly showed enrichment in lysosome and amino sugar metabolism pathways. Full article