Public transit networks structure social and economic activities by bringing diverse populations together in shared spaces. This study examines the spatial relationship between faregate replacements and nearby crime patterns within the Washington Metropolitan Area Transit Authority (WMATA) Metrorail network in the District of Columbia, Montgomery County, and Prince George’s County, Maryland. Faregate replacements were implemented system-wide across all 98 Metrorail stations between July 2023 and September 2024; however, the rollout was staggered, and precise completion dates were not uniformly documented for all stations. This study therefore uses the seven stations with verified replacement dates as treatment stations and uses propensity score matching (PSM) to select seven control stations based on pre-intervention property and violent crime levels to assess changes in nearby crime patterns following the intervention. These stations constitute the earliest confirmed interventions, allowing for a before-and-after comparison and a quasi-experimental design with temporal precision. We use a spatial analytical approach employing the weighted displacement quotient (WDQ) and negative binomial difference-in-differences (DID) models to analyze property and violent crime patterns between the pre- and post-intervention periods (2022 and 2024). This approach examines Census blocks in street-network buffers of 0–400 m, 400–800 m, and 800–1,200 m around stations. The results indicate statistically significant reductions in property crime within the 0–400 m treatment area, with weaker effects at greater distances from stations. In contrast, violent crime exhibited no statistically significant changes following faregate replacement, suggesting that the effects of access-control interventions may differ across crime types. This study highlights the significance of considering interventions in the built environment and, more broadly, underscores the need for urban policy to account for the broader social consequences of transportation design.
High-entropy oxides (HEOs) represent a class of functional materials whose interfacial chemistry and colloidal behavior remain poorly understood, limiting their development for demanding applications. This work establishes how compositional complexity in multielement oxide systems governs both colloidal stability and functional performance through a systematic investigation of eight HEO compositions in pool boiling experiments, where thermal gradients and active nucleation simultaneously test these properties under demanding conditions. Results demonstrate that HEOs with five or more equimolar elements exhibit enhanced dispersion stability compared to lower-entropy oxide systems due to configurational entropy effects, providing thermodynamic resistance to particle aggregation. Configurational entropy values of 13.38-14.90 J/mol·K exceed the critical 1.5R threshold for entropy-stabilized phases. Y-HEO, featuring yttrium combined with equimolar Co, Cr, Fe, Mn, and Ni, achieved superior performance with a 63% critical heat flux enhancement and a 135% heat transfer coefficient improvement relative to the deionized water baseline at 0.05 wt % concentration. Comprehensive surface characterization revealed that multielement oxide composition creates unique interfacial properties: contact angle reduced from 96° to 62°, minimal hysteresis of ∼12° enabling rapid rewetting, and surface roughness increased by 170%, establishing abundant nucleation sites with dramatically reduced superheat requirements. These combined effectsenhanced colloidal stability from configurational entropy, superior interfacial chemistry from compositional heterogeneity, and optimized wettability from multielement cation coordinationsynergistically produced exceptional thermal performance. This work demonstrates that the precision design of multielement oxide composition directly translates fundamental materials chemistry principles into functional advantages in thermal applications.
A left ventricular assist device (LVAD) is a mechanical pump that provides circulatory support as a bridge-to-cardiac transplantation or as a destination therapy in patients with advanced heart failure. A potential adverse event of LVAD support is thrombus ingestion or formation, which may then travel through the device into the cerebral arteries, causing ischemic strokes. Previous numerical simulations of embolus transport within LVAD systems have exhibited inconsistencies in the results in assessing the fate of emboli in LVAD settings. These disparities prompted the development of an experimental framework tailored for a systematic measurement of particle transport in the context of LVADs. In this in vitro study, we utilized a nearly refractive-index-matched time-resolved particle tracking velocimetry (PTV) system to resolve and visualize particle trajectories within each aortic model, complemented by particle image velocimetry (PIV) measurements. We also conducted a meticulous measurement of particle weight in each individual branch by collecting the particles from each outlet. Four LVAD patients, as well as two idealized models of the human aorta, each featuring a cannula grafted at an anastomosis angle of 45 degrees, were considered. Thin-wall high-resolution phantoms of these models were 3D-printed with precision and placed in a flow loop that provided physiological flow conditions. Three different sizes of precision fluorescent beads (neutrally buoyant) with particle-to-cannula diameter ratios of d_p/D = 0.031, 0.053, 0.075 were used to replicate emboli at two clinically relevant flow rates, spanning over 50 experimental cases combined. This systematic investigation reveals that particle distributions largely follow the branchwise flow split, nearly independent of the range of Stokes numbers and inlet Reynolds numbers examined. This finding partially challenges commonly held assumptions in LVAD studies.
Marijuana is the most widely used illicit drug in the United States. The recent legalization of marijuana has shifted public opinion, which might affect how people report drug-related activities. Whereas some studies have investigated the issue at the city or larger scales, few have focused on a microlevel within a city. This study examined the spatiotemporal distribution of drug-related calls at the street segment level in Cincinnati, Ohio, from 2013 to 2019, to test if the legalization of medical marijuana on 8 September 2016 had an impact. Results indicated that the seasonal drop in calls was steady after the legalization, except for an immediate increase from fall 2015 to fall 2016, which is probably due to a lag effect from the peak volumes of calls in spring and summer of 2016. The spatial distribution of the calls became more concentrated. Using a combination of zero-inflated negative binomial regression model and interrupted time-series analysis, this study confirmed that the effects of medical marijuana legalization on drug-related calls were statistically significant, with the spatial lag, the socioeconomic variables, crime generators and attractors, and the season dummy variable controlled. This research enhances our understanding of the relationship between medical marijuana legalization and drug-related calls at the street segment level and provides a method that can be applied in other areas. Findings on the increasing concentration of drug-related calls have important policy implications. The police department should consider developing more targeted intervention strategies that focus on areas with a high concentration of such calls.
To perform a narrative review of the biomechanics of lumbar pedicle subtraction osteotomies (L-PSO) and associated surgical constructs. A non-systematic literature search was performed. PubMed was queried for investigations published between 2010 and 2025 with the following search terms: “lumbar”, “PSO”, “biomechanics, “finite element analysis”, “cadaver”. Studies evaluating biomechanical properties of L-PSO (L1-L5) constructs were included. Clinical studies and non-lumbar level (cervical/thoracic) PSOs were excluded. L-PSOs create a highly destabilized environment, particularly in axial rotation. Two-rod constructs significantly reduce range of motion (ROM) relative to the uninstrumented spine but are associated with high rod stresses. Multi-rod constructs (satellite and accessory rods) consistently reduce ROM and primary rod stresses, although the magnitude of benefit varies across studies and configurations. Rod material (cobalt chrome) and increased rod diameter further enhance construct rigidity but may increase stress shielding. Cross-links may increase rod stress when placed near a L-PSO site, while monoaxial screws increase construct stiffness compared to polyaxial screws. Interbody cages placed adjacent to L-PSOs improve load sharing and reduce posterior rod strains, particularly when used in a “sandwich” configuration. Biomechanical improvements, such as reduced rod strain and ROM, have not been directly linked to clinical outcomes, including fusion rates or rod fractures. While biomechanical studies demonstrate multi-rod constructs and adjunct techniques improve construct stability, the relationship between these biomechanical advantages and clinical outcomes, including osseous healing and rod fractures, remains unclear. In L-PSOs, increasing construct rigidity alone is not the primary goal; instead, optimal load sharing across the osteotomy site is a critical biomechanical consideration. As such, future work should focus on elucidating the optimal balance between protecting posterior instrumentation through construct rigidity and preserving adequate compressive forces across L-PSOs, integrating biomechanical findings with clinical data, and developing patient-specific biomechanical modeling to further refine L-PSO instrumentation techniques.
