We present a model of a crawler consisting of several suction units distributed along a straight line and connected by springs. The suction units are rudimentary proprioceptors-actuators, which sense binary states of compression versus elongation of the springs and can either adhere or remain idle. Muscular contraction is not controlled by the crawler but follows an endogenous, stereotyped wave. The crawler is tasked to learn patterns of adhesion that generate thrust in response to the wave of contraction. Using tabular Q-learning we demonstrate that crawling can be learned by trial and error and we ask what are the benefits and limitations of distributed versus centralized learning architectures. We find that by centralizing proprioceptive feedback and control, the crawler leverages long-range correlations in the dynamics and ride the endogenous wave smoothly. The ensuing benefits are measured in terms of both speed and robustness to failure, although they come at increased computational cost. At the opposite extreme, purely distributed feedback and control only leverages local information and yield a jerkier and slower crawling, although computationally cheap. Intermediate levels of centralization can negotiate fast and robust crawling while avoiding excessive computational burden, demonstrating the computational benefits of a hierarchical organization of crawling. Our model unveils the trade-offs among crawling speed, robustness to failure, computational cost, and information exchange that may shape biological solutions for crawling and could inspire the design of robotic crawlers.
This study aimed to ascertain the relationship, if any, between prone newly-born infants' achievement of the crawling behavior described in Widström's 9 stages during immediate, continuous skin-to-skin with their mother during the first hour after birth and effective breastfeeding in the following 24-h. This observational descriptive study filmed 149 mothers who gave birth vaginally, January-February 2024, at a regional referral hospital in Uganda while skin-to-skin during the first hour after birth. Crawling behaviors, one of Widström's 9 instinctive stages of newborns after birth, were noted. Breastfeeding was assessed within 24 h of the birth and prior to discharge using the Lactation Assessment and Comprehensive Intervention Tool. Pearson's Chi square was used to determine the statistical significance between the behavior of crawling during the first hour after birth, and effective breastfeeding (defined as bursts of 1:1 or 2:1 swallow ratio by cervical auscultation and/or observed rocker motion of the jaw) before discharge. Fifty newborns (33.6%) crawled in the first hour after birth during skin-to-skin contact. Crawling was significantly associated with effective breastfeeding before discharge (χ2(1, N = 149) = 6.97, p = .008), with both suck-swallow bursts (χ2(1, N = 127) = 8.57, p = .003) and rocker jaw motion (χ2(1, N = 119) = 4.77, p = .029). The results of this study support the relationship between crawling toward the breast while prone during skin-to-skin contact in the first hour after birth and effective breastfeeding before discharge. Observing crawling behavior may help clinicians identify dyads who need priority breastfeeding assessment and support prior to discharge, particularly in low-resource settings.
This study aimed to analyze sex differences in the rate of force development (RFD) among the arm stroke only (As), the leg kick only (Lk), and the full stroke (Fs) through the 30-s front crawl tethered-swimming (TS) test, and to discuss the correlation between RFD variables and short-distance front crawl speed in the force-time (F-t) curve across different sexes. Sixteen male and fourteen female highly trained swimmers (age: 19.7 ± 3.27 years) performed the TS test under three conditions: As, Lk, Fs, as well as a 25-m front crawl test. The As, Lk, Fs of the peak RFD per 5 s (RFDave), and maximum value of the peak RFD every 5 s (RFDmax) had highly significant correlation with V25, V50, and V100 (V25-V100). Notably, the Fs of the male RFD and the As of the female RFD showed particularly strong correlations with V25-V100. It was also observed that there were sex-specific disparities in the RFD indices associated with the As, Lk, and Fs phases of swimming. The findings indicate that the RFD within the F-t curve is a valuable variable for assessing the capacity to generate propulsive force in water. Sex factors affect the relationship between RFDave, RFDmax, and short-distance front crawl speed in swimming. Coaches should fully consider sex differences when training for swimming propulsive force.
During epithelial morphogenesis, cell polarity aligns individual cell behaviors into collective motions that shape developing tissues. Here, we combine experiments with computational modeling to investigate how cell-scale forces oriented by planar cell polarity (PCP) direct the collective, counter-rotational cell flows that occur during hair placode morphogenesis. Unexpectedly, we find that junctional myosin and PCP protein localization are not co-correlated with junction shrinkage, indicating the role of PCP during placode polarization is not to direct apical neighbor exchanges. Instead, we find that PCP directs anterior-directed crawling of placode cells along the basal surface of the tissue through a mechanism that requires integrins and the cell-crawling regulator Rac1. Modeling the placode as a three-dimensional continuum viscoelastic fluid, we find that active forces from cell crawling at the basal surface are sufficient to generate the experimentally observed counter-rotational cell motion at the apical surface. Our results show an unexpected role for PCP in epithelial morphogenesis, centering the basal surface as the site of force generation.
Post-activation performance enhancement (PAPE) has been proposed as an acute strategy to improve explosive performance, yet its effects on sprint-swimming performance remain unclear, particularly when individualized recovery timing is considered. This study examined the acute effects of a lower-limb PAPE protocol, applied using an individually determined recovery time (IRT), on 50 m front crawl performance and selected start-, race-, and turn-related kinematic variables in national-level male swimmers. Fourteen male national-level swimmers completed a randomized repeated-measures cross-over design comprising control (CON) and PAPE conditions. In the PAPE condition, swimmers performed a lower-limb conditioning protocol consisting of loaded lunge-position squats on a Keiser Squat machine, followed by a maximal 50 m front crawl trial at the end of the IRT. In the CON condition, swimmers completed the same swimming trial without the conditioning stimulus. Lower-limb power output increased significantly after the conditioning activity and reached its highest mean value at 6 min post-exercise (F4,52 = 97.14, p < 0.001). However, the PAPE protocol did not significantly improve overall 50 m performance (25.508 ± 0.856 s vs. 25.529 ± 0.773 s; mean difference = - 0.021 s, 95% CI: -0.148 to 0.107; p = 0.731) or most start-related variables. The only significant effect was observed for turn time, which was lower in the PAPE condition than in CON (7.707 ± 0.251 s vs. 7.771 ± 0.261 s; mean difference = - 0.064 s, 95% CI: -0.126 to - 0.001; p = 0.046). Responder analysis revealed substantial inter-individual variability across outcomes. In conclusion, a lower-limb PAPE protocol applied using the IRT did not improve overall 50 m front crawl performance in national-level male swimmers, although it produced a small improvement in turn time. These findings suggest that the effects of lower-limb PAPE in sprint swimming may be segment-specific rather than global, and that practical implementation should be individualized rather than applied uniformly across swimmers.
Post-activation performance enhancement (PAPE) has been proposed as an acute strategy to improve sprint performance, yet evidence in swimming remains inconsistent, particularly for upper-limb protocols and segment-specific race outcomes. This study examined the acute effects of an individually timed upper-limb PAPE procedure on 50 m front crawl performance and selected race-kinematic variables in national-level male swimmers. Fifteen swimmers completed a randomized repeated-measures cross-over design comprising a control condition (CON) and an upper-limb PAPE condition. The PAPE procedure consisted of 3 sets of 6 repetitions of a prone butterfly-style double-arm pull exercise at 70% 1RM on a Keiser Functional Trainer, followed by a maximal 50 m front crawl trial performed after each swimmer's individually determined recovery time. The primary outcome was 50 m race time (T50), while start-, split-, turn-, and lap-specific stroke variables were analyzed as secondary exploratory outcomes. Compared with CON, the PAPE condition resulted in significantly faster T50 (25.44 ± 0.80 vs. 25.70 ± 0.78 s; Δ = -0.260 s, - 1.01%; p < 0.001) and T50 excluding reaction time (p < 0.001). Significant improvements were also observed for T15, T20, dive distance, flight time, turn time, and second-length stroke rate, whereas lap-specific swimming velocity, stroke length, and stroke index remained unchanged. These findings suggest that an individually timed upper-limb PAPE procedure may improve 50 m front crawl performance in national-level male swimmers, with effects expressed mainly through selected race segments rather than a uniform enhancement of free-swimming efficiency.
The Army Trauma Training Course (ATTC) has held the responsibility of training deploying U.S. Army Forward Resuscitative and Surgical Detachments (FRSDs) since September 2001. The program of instruction (POI) consists of didactics and skill stations (Crawl), a mass casualty (MASCAL) situational training exercise (STX) (Walk), and clinical integration into an urban Level I trauma center (Run). Over the program's 25-year existence, there has been no report on the subjective assessment of the rotator's perceived effectiveness of the program as a whole. We hypothesized that a post-course survey would evaluate the POI at the ATTC and that ATTC graduates would subjectively describe improved operational readiness. Post-course surveys were delivered electronically to rotating FRSDs as a graduation requirement. Survey questions were developed on a 5-point Likert scale, and descriptive statistics were calculated. Survey data were analyzed from 25 courses (October 2021 through December 2023), including 485 FRSD members. There were 41 general surgeons, 19 orthopedic surgeons, 48 emergency medicine physicians, 51 CRNAs, 53 critical care nurses, 48 emergency room nurses, 7 other nurses, 57 LPNs, 82 combat medics, 50 surgical technicians, 6 physician assistants, and 23 medical service corps officers. The post-course survey response rate was 441/485 (90.9%), with nearly all respondents answering the entire survey. Among respondents, 402/440 (91.4%) respondents agreed that the MASCAL STX better prepared them to manage a MASCAL scenario; 410/441 (93.0%) respondents agreed that clinical rotations were useful for FRSD team development; 401/440 (90.9%) respondents agreed that their experience at ATTC made them more confident in performing their Individual Critical Task List (ICTL) skills in the deployed setting; 402/424 (94.8%) respondents agreed that their experience at ATTC made them more knowledgeable of the Joint Trauma System (JTS) Clinical Practice Guidelines (CPGs); 398/425 (93.6%) respondents agreed their experience at ATTC contributed favorably to their operational readiness; and 437/441 (99.1%) respondents indicated they would recommend the course to another deploying FRSD. POI at the ATTC subjectively improves FRSD collective and individual preparedness for deployed combat casualty care. Further studies are needed to evaluate the objective effectiveness of the training platform.
Gecko-inspired soft robots offer unique advantages for confined-space operations. Here, we introduce a soft climbing robot designed for tasks such as spacecraft inspection and disaster response. Unlike conventional attachment mechanisms relying on claws, suction-based adhesion, or electromagnetic components, the proposed system integrates polyurethane-based dry adhesive footpads, which passively adapt to a wide range of surfaces and require no external power. A key innovation of this work is the incorporation of variable stiffness footpads capable of actively tuning their mechanical properties in response to surface interaction demands, thereby optimizing both attachment stability and detachment efficiency during locomotion. Experimental characterization indicates that these footpads achieve an adhesion-to-detachment force ratio of 11:77, demonstrating a favorable balance between strong attachment and reliable release. Furthermore, the robot integrates a bioinspired crawling mechanism that synchronizes limb actuation with the deformation of a flexible spine structure, effectively enhancing propulsion and maneuverability across irregular terrain. Validation experiments conducted on diverse surface types confirm the robot's environmental adaptability and highlight its potential for deployment in constrained, unstructured, and dynamically changing operational contexts.
While core strength is theorized to be crucial for swimming performance, empirical evidence remains conflicting, and the perspectives of high-performance coaches-key stakeholders in training prescription-are largely unexplored. This qualitative study examined the perceptions of eight expert Chinese swimming coaches (seven males, one female) regarding the role of core strength in front crawl performance and explored how and why they prescribe core-specific training. Semi-structured interviews were conducted, transcribed verbatim, and analyzed using thematic analysis. Results revealed three central themes. First, all coaches unanimously affirmed core strength's importance through dual mechanisms: direct (force transmission, rotational power) and indirect (stabilization, drag reduction). Second, despite this consensus, assessment and training methods relied primarily on experiential knowledge rather than evidence-based protocols. Third, a "threshold effect" was identified, wherein coaches' experiential knowledge suggested that core training benefits may be most apparent in athletes with initial deficiencies. Based on these findings, we propose a conceptual model positing that core function operates through direct and indirect pathways, moderated by baseline capacity and transfer effectiveness. The model provides a testable framework to guide future research on how, when, and for whom core training is most effective, underscoring the need for swimming-specific diagnostic tools and integrated training protocols.
N-(1,3-Dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-quinone or 6PPD-Q) is an oxidation product of 6PPD, an antioxidant used in tires to prevent rubber degradation, that has been associated with high mortality in juvenile coho salmon at concentrations as low as 95 ngL⁻¹. While research has focused primarily on fish, the effects of 6PPD-Q on freshwater invertebrates remain limited. In this study, we assessed the toxicological impact of this contaminant on the freshwater snail Ampullaceana balthica over a 10-day experiment under two different temperature conditions. A. balthica was chosen because it is widely distributed in temperate and Mediterranean regions and is commonly used as a model organism in environmental toxicology studies. Although 6PPD-Q had a limited impact on embryonic hatching, adult snails experienced significant effects on reproduction, growth, and motility, with more pronounced impacts at higher temperatures. Specifically, 6PPD-Q reduced clutch and egg production, particularly during the first days of exposure. Elevated temperature increased reproduction, but its interaction with 6PPD-Q lowered the overall reproductive output. The combined stressors also impaired growth, motility and embryo development. These sublethal effects may lead to population declines and cascading impacts on freshwater community structure and ecosystem functioning, particularly under climate change scenarios. This highlights the urgent need for comprehensive risk assessments of emerging contaminants such as 6PPD-Q to better understand their ecological impacts.
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Coordinated movement along the body axis is critical to locomotion. In segmented, limbless animals, anterior (head) and posterior (tail) segments play different roles in locomotion, leading to a need for flexible coordination across body regions. Larval Drosophila melanogaster present a tractable experimental model for limbless, segmented crawling given the extensive genetic tools available and the optical clarity of the body. Prior work has suggested that, during crawling, all larval body segments contract similarly, despite the fact that each crawl cycle comprises two overlapping phases: a piston involving the most posterior segments and a peristaltic wave involving all body segments. To test whether coordination varies regionally during locomotion, we expressed GCaMP in body wall muscles of larvae of either sex and recorded segmental contraction kinematics and muscle recruitment during many cycles of locomotion in linear channels. Facilitated by machine vision techniques, we discovered new features of larval crawling at multiple scales. First, the propagation of both contraction and recruitment waves slowed approaching mid-body segments, then sped up toward the head. Second, the timing relationship between contraction and recruitment waves could be highly variable in anterior segments. Third, contraction durations showed particularly strong intersegmental correlations among posterior segments. These data suggest posterior segments coordinate to power the piston phase, while anterior segments tolerate greater flexibility to enable reorienting behaviors. Our results depict an unanticipated degree of axial heterogeneity in the coordination of limbless crawling, opening new avenues to study the origins of whole-body coordination and the consequences of segmental diversity for locomotion.
Individual transactions involving pharmaceutical products via social networking service (SNS) are considered an inappropriate distribution route and may serve as a guise for illicit business-to-consumer activities. In Japan, individual transactions of pharmaceutical products via the internet are recognized as inappropriate distribution routes, which not only lead to the inappropriate use of pharmaceutical products but also require more active monitoring and guidance from the viewpoint of pharmaceutical security and quality assurance. This study aimed to develop a method to accurately detect SNS tweets suspected of involving individual transactions of pharmaceutical products, using text data from Twitter (subsequently rebranded as X), the primary platform for such activities in Japan. We applied text mining to 1389 text tweets suspected of involving individual pharmaceutical transactions. Using the hashtag "#Okusuri mogumogu," which was identified through manual searching and is commonly associated with trading psychotropic pharmaceuticals, we collected 7499 tweets posted in 2022 and 6461 tweets posted from January 1 to March 31, 2023, using our web crawler program. After manually categorizing whether each tweet was related to individual pharmaceutical transactions, we extracted words and summarized their occurrences and frequencies using the 2022 dataset. A decision tree model was then generated using the 2022 dataset and validated using the 2023 dataset to evaluate the reliability of detecting transaction-related tweets. Using web crawling, the number of tweets identified using the hashtag "#Okusuri mogumogu" was 7499 in 2022 and 6461 in the first 3 months of 2023. The crawling results also showed that the number of detectable tweets increased closer to the crawl date, suggesting that SNS tweets may frequently be deleted. From 3228 extracted words in the 2022 dataset, 452 were significantly associated with tweets suspected of involving individual transactions. Highly indicative terms included "kyuu" (request), "yuzuri" (transfer), "DM" (direct message), and transaction-related hashtags. The chi-square automatic interaction detection model demonstrated stable discriminative performance (area under the receiver operating characteristic curve values: training 0.83 and 0.84; Gini coefficient: training 0.65 and test 0.68). The overall accuracy using the 2023 validation dataset was 82.31%, indicating reasonable generalizability despite linguistic fragmentation and the presence of partial word forms characteristic of Japanese text. Using transaction-related tags, text mining, and machine learning, we identified key terms linked to individual pharmaceutical transactions and developed a predictive model. This approach may aid in preventing inappropriate online transactions of pharmaceutical products.
Beetroot juice (BRJ) has been proposed as an ergogenic aid due to its high nitrate content, yet evidence from field-based studies in elite swimmers remains limited. This study investigated the acute effects of concentrated BRJ ingestion on performance and physiological responses during repeated maximal 200-m front-crawl efforts in elite male swimmers. Twelve elite swimmers (age: 20 ± 2 years, body fat: 7.1% ± 2.5%, 200-m personal best: 115.7 ± 3.4 s) completed a randomized, double-blind, counterbalanced trial. Participants consumed either 140 ml of concentrated BRJ (Beet It Sport) or a custom-made, nitrate-depleted placebo (PL) matched for sensory characteristics, 2 hr before performing two maximal 200-m front-crawl time trials, separated by 60 min of passive recovery. Blood samples were collected upon arrival and immediately after each time trials, and 200-m completion time, blood lactate concentrations, and ratings of perceived exertion were recorded. No significant differences were observed in completion time for either the first (PL: 116.7 ± 3.0 vs. BRJ: 117.2 ± 3.1 s, p = .19) or the second 200-m time trial (PL: 117.8 ± 2.6 vs. BRJ: 117.8 ± 3.3 s, p = .98), nor in the change between trials (PL: 1.1 ± 1.5 vs. BRJ: 0.5 ± 1.3 s, p = .40). Likewise, lactate concentrations and ratings of perceived exertion values did not differ between conditions (p > .05). In conclusion, acute BRJ supplementation did not enhance 200-m front-crawl performance, lactate responses, or perceived exertion in elite swimmers under competition-like conditions.
An origami worm-inspired robot is developed to achieve multimodal locomotion and multifunctional operation within confined and complex pipeline environments. The robot integrates eight Yoshimura-origami crawling modules driven by pneumatic muscles, two rolling modules with deployable flaps, and a shape-memory alloy (SMA)-actuated waterbomb gripper, forming a compact and modular mechatronic system. A unified gait-generation framework enables 25 distinct locomotion gaits, including earthworm-like peristaltic crawling (rectilinear, sidewinding, and circular), inchworm-like two-anchor crawling, and bidirectional wheel-rolling. Kinematic modeling predicts performance across modes and exhibits qualitative agreement with experiments, with deviations attributed to stick-slip and frictional effects. The robot demonstrates robust mobility in a complex industrial pipeline scenario involving inclined, curved, variable-diameter, and discontinuous pipes, as well as vertical detection and large-diameter traversal. Coordinated actuation between the pneumatic and SMA systems allows effective grasping and swallowing-like manipulation of objects with varied stiffness. The integrated design achieves high maneuverability, environmental adaptability, and functional versatility, providing a promising platform for inspection, detection, and maintenance tasks in constrained engineering environments.
The development of infant posture is shaped by a complex convergence of intrinsic abilities and environmental contexts. This longitudinal study examined how infants' postural engagement evolved across the first year of life, focusing on the roles of motor skill acquisition and movement context alongside age. Using naturalistic home video data, we tracked the frequency, duration, and diversity of postures across over 180 observations. Our findings reveal that postural transitions and engagement patterns shift dynamically with skill status and movement contexts (restrained vs. unrestrained), rather than following a linear age-based trajectory. Movement context effects were posture-specific: supine posture declined with age only in the unrestrained context; belly-on-the-floor posture declined with age overall; sitting flipped with skill - pre-sitters sat more in the restrained context, whereas sitters sat more in the unrestrained context; crawling showed no main effect of age but differed by crawling status, with an age × crawling status interaction; and upright increased modestly with age and showed the largest unrestrained context advantage, especially among cruisers. These results highlight the importance of considering how multiple interacting factors, not just chronological age, contribute to early postural development, extending skill-based accounts of motor development by demonstrating that movement context interacts with skill status in posture-specific ways.
In-pipe robots must navigate narrow, curved passages where rigid mechanisms often require bulky steering units. Soft crawlers offer better compliance but typically rely on multiple actuators or reconfigurable contacts to achieve multi-directional motion. Drawing inspiration from biological soft crawlers that exploit directional friction and coordinated anchor-slip patterns, this study focuses on locomotion principles observed in caterpillars, water boatmen, and whirligig beetles. Based on these bioinspired concepts, we present a tendon-driven soft in-pipe robot that combines continuum bending-twisting deformation with modular anisotropic friction pads (AFPs), enabling three locomotion modes using only two motors. AFP inclination, curvature, and ridge geometry were optimized through friction tests, constant-curvature modeling, and finite element analysis to enhance directional adhesion on flat and curved surfaces. A deformation-based locomotion framework was developed to couple tendon actuation with friction orientation, achieving longitudinal crawling, transverse translation, in-place rotation, and smooth transitions via programmed twisting. Driving experiments demonstrated repeatable anchor-slip locomotion with average speeds of 28.6 mm/s, 15.7 mm/s, and 11.5°/s for the three modes. Pipe tests in straight, curved, and T-junction sections further validated stable contact and reliable gait transitions. These findings highlight the potential of friction-programmed continuum robots as compact, bioinspired platforms for advanced in-pipe inspection and diagnostic tasks.
Owing to their excellent electromechanical (EM) response, poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))-based ferroelectric polymers (FEPs) are extensively utilized in soft actuators. Currently, the strain (S33) of FEPs is mostly identified as electrostriction and described by S33 = Q33P2. Wherein, Q33 represents the electrostriction coefficient, P is polarization, and Q33 is mainly derived from data fitting. However, this approach fails to establish a connection between the composition and structure of FEPs, hindering the design of FEPs with higher EM response performance. This study introduces an effective model that quantitatively correlates the structural parameter interplanar spacing (d) to the EM response, namely Q33 = 100(Δd/d0+1) × Q33(s), where d0 = 4.31 Å, Q33(s) = -0.54 m4/C2 are from single P(VDF-TrFE). Guided by this model, we tailored the electrical properties and d of FEPs by incorporating 1,5-Dihydroxy-2,2,3,3,4,4-Hexafluoropentane (HFPD), which results in a substantial improvement in the S33 by up to 100%. The composite films show promising application in fabricating high-performance soft robots, including a biomimetic crawler (with a ultra-fast crawling speeds of 27 cm/s) and a biomimetic butterfly (with a thrust-to-weight ratio of 0.71). Overall, our findings offer new insights for designing FEPs with superior EM responses, potentially driving notable advancements in flexible actuators.
Epithelial wound healing is an essential process in multicellular organisms, primarily driven by lamellipodia-based crawling, purse-string contraction, and collective cell migration. One or more of these mechanisms participate in healing a wound, yet the choice, sequence, and coordination of these processes are poorly understood. Moreover, different mechanisms dominate in different tissues, organisms, wound types, and wound sizes, further complicating our understanding of how cells select among healing mechanisms. In this study, we analyzed wound healing across wound types and spatial scales in the basal eukaryote Clytia hemisphaerica (Clytia) to establish a unified model for mechanism selection within a single organism. We demonstrate that lamellipodial crawling and actomyosin cable contractions are sequential, partially redundant processes involved in healing all wounds. Furthermore, the exposure of the basement membrane acts as a central regulatory cue, orchestrating lamellipodia formation, actomyosin contraction, and collective cell migration responses. Remarkably, we discovered that these same mechanisms operate in healing micro-wounds internal to a single cell. This work fundamentally advances our understanding of how diverse healing mechanisms are coordinated to respond to all types of wounds, while the use of a basal metazoan model expands our knowledge of fundamental strategies for maintaining epithelial integrity.
Whole-organism toxicity assays are essential for evaluating the safety of chemicals, but mammalian models remain costly and low throughput, contributing to a global backlog of untested chemicals. The micro-organism C. elegans has emerged as one of the new approach methodologies (NAMs) modelling toxicological responses across multiple interacting tissues, with advantages of human-relevant biology and cost-effectiveness. However, existing technologies for C. elegans toxicity testing are limited by poor compatibility with long-term chemical exposure, lack of multiplexibility, and inability to dynamically modulate chemical exposure over time. Here, we present a novel microfluidic platform, passive nematode culture chambers (PNCs) integrated into well plates - where micropillar arenas housing crawling or swimming C. elegans have fluid communication with the surrounding medium, enabling consistent nutrient access and long-term viability. These integrated well plates allow multiplexed assays and high-quality imaging due to worm motion being restricted to two-dimensions. We demonstrate the utility of these microfluidic well plates for whole-organism lethality assays. Dose-response studies were conducted with 11 chemicals, revealing median lethal concentrations (LC50s) consistent with values obtained in existing liquid culture and microfluidic systems. The LC50 values from PNC well plates showed strong concordance with median lethal dose data from rats (Spearman correlation, r = 0.827), suggesting that the platform is informative for comparative toxicity ranking. We demonstrate the uniqueness of the PNC well plates by (i) incorporating arenas of varied micropillar spacing and showing that crawling and swimming worms respond differently to heavy metal toxicity due to differences in toxin uptake, (ii) conducting dynamic exposure studies using cadmium chloride (CdCl2), uncovering distinct temporal toxicity patterns and distinguishing between interrupted and chronic exposure insights that would be difficult to obtain using conventional technologies. These findings establish PNC microfluidic well plates as a robust platform for C. elegans-based toxicology. Beyond their immediate application in chemical safety assessment, PNC well plates also enable new experimental directions where minimal intervention, multi-day viability, and scalability are critical.