Test out our new Bento Search

No summary available.

No summary available.

No summary available.

Semiflexible polymer networks are ubiquitous in biological systems, including a scaffolding structure within cells called the actin cytoskeleton. The polymers in these networks are interconnected by transient bonds. For example, actin filaments in the cytoskeleton are physically connected via cross-linker proteins. The mechanical and kinetic properties of the cross-linkers significantly affect the rheological properties of the actin cytoskeleton. Here, we employed an agent-based model to elucidate how the force-dependent behaviors of the cross-linkers determine the material properties of passive networks without molecular motors and the force generation of active networks with molecular motors. The cross-linkers are assumed to behave either as a slip bond, whose dissociation rate increases with forces, or as a catch-slip bond, whose dissociation rate decreases with forces at low force level but increases with forces at high force level. We found that catch-slip-bond cross-linkers can simultaneously increase both the stress and the strain at the yield point. Through a systematic variation in the force dependence of the catch-slip bonds, we identified the specific parameter regimes that enable network reinforcement and enhanced extensibility simultaneously. Specifically, we found that a sufficiently large force threshold for the catch-slip transition is essential for maintaining dynamic force-bearing elements that turnover continuously—a mechanism not achievable with slip bonds. Additionally, we demonstrate that such force-dependent redistribution of the catch-slip bonds substantially enhances internal contractile forces generated by a motor in active networks.Statement of significance Polymer networks are ubiquitous in industrial and biological systems. The polymers in these networks are often interconnected by transient bonds. The transient bonds behave as a slip bond whose dissociation rate is proportional to forces or as a catch-slip bond whose dissociation rate decreases with increased force (catch) at low force level but increases with increased force (slip) at high force level. In this study, we computationally tested different types of catch-slip bonds to define how the material properties of polymer networks are fine-tuned by each property of molecular bonds. We found that catch-slip bonds can increase both stress and strain at a yield point, which is impossible to achieve without the catch-slip bonds.

Abstract Background Congenital cytomegalovirus (CMV) infection is a major cause of neonatal morbidity. However, optimizing ganciclovir (GCV) dosing in preterm infants is complicated by immature renal function and developmental pharmacokinetics. Population pharmacokinetic (PPK) parameters for GCV and valganciclovir (VGCV) have been reported, but data remain limited for extremely low birth weight infants. We aimed to characterize longitudinal changes in GCV clearance in a preterm infant with congenital CMV infection using Bayesian modeling. Methods GCV/VGCV were administered over a 15-week period, with concurrent therapeutic drug monitoring. Individual parameters were estimated using a previously published PPK model and a postnatal age-based maturation function in NONMEM. Scr clearance was measured at two time points using the 24-h urine collection method. Results GCV clearance increased from 0.048 to 0.273 L/hr/kg from postnatal day 30 to day 93, whereas VGCV bioavailability remained stable (~ 52–55%). Scr clearance values matched estimated GCV clearance, supporting the validity of the model. The maturation function indicated that tubular secretion likely contributes to accelerated drug elimination. Late-phase GCV clearance exceeded typical glomerular filtration rate, indicating possible catch-up in renal function. Conclusion Renal maturation should be considered in addition to body weight when adjusting GCV dosing in preterm infants. This case highlights the importance of aligning individualized dosing strategies with the developmental physiology of preterm neonates.

Theorising Oliver Jeffers’ Picturebooks: From How to Catch a Star to Now examines semiotic, affective and metafictive storytelling in Oliver Jeffers’ postmodern picturebooks from a multi-theoretical approach. This volume provides fresh insight into Jeffers’ iconotextual narratives through textual and visual analysis, exploring how his multimodal texts construct childhood and evoke emotional resonances. The book deconstructs the postmodernity of these narratives, highlighting Jeffers' contemporary methods of storytelling through an exploration of the texts’ metafictive and self-reflective elements. From How to Catch a Star (2004) to Where to Hide a Star (2024), this book journeys through the mindscapes of Jeffers’ design and analyses the nuances of metafictive storytelling from a postmodern perspective.

Gill nets are widely used in small-scale fisheries because of their simplicity and efficiency, particularly for capturing demersal and pelagic species. This study analyzed the catch characteristics of bottom-set gill nets with a 5.08cm mesh size during the evening (7:00-8:30 PM) and pre-dawn (4:00-5:30 AM) periods in Inner Ambon Bay, Indonesia. A total of 30 fishing trips were conducted, and data on species composition, catch diversity, and length frequency distribution were collected. The results revealed significant temporal variation in species composition and dominance. In the evening, Selar crumenophthalmus was the most dominant species (64.57%), whereas its proportion decreased to 38.15% in the pre-dawn period, accompanied by an increase in Upeneus moluccensis (19.61%). Diversity indices (Shannon-Wiener) indicated moderate diversity, with higher values during the pre-dawn period (1.51) than during the evening (1.36). Dominance was lower in the pre-dawn period (0.09) than in the evening (0.44). Length frequency analysis showed that the gilled method was the most effective capture mechanism, selectively targeting fish in the 21.5-22.5cm range. These findings emphasize the influence of fishing time on catch composition and size selectivity, providing insights for optimizing fishing practices and supporting sustainable fishery management in Inner Ambon Bay. [ABSTRACT FROM AUTHOR]

Accuracy of catch landing data reported by captains of commercial vessels is crucial in the assessment of marine species stocks and in fisheries policy and management. However, this data can be subject to estimation biases, such as a tendency to inflate some catches (to the detriment of others) and refusal to fill in logbooks. We assessed the accuracy of catch reports from the Spanish tropical tuna purse seine fleet (which accounts for 26% of catches in the Indian Ocean) using Benford's law, a mathematical principle effective for detecting irregularities across multiple datasets. During 2013–2020, including periods before and after the implementation of total allowable catch (TAC) limits in 2017, reported catches differed from Benford's expected distribution, especially for bigeye tuna, indicating potential inaccuracies in reported catches. Changes in data reporting after TAC limits were imposed in 2017 suggested modifications in fishing operations and reporting practices. Use of Benford's law highlighted its potential as an auditing tool in fisheries management and provided insights into data integrity that are crucial for sustainable fisheries governance. [ABSTRACT FROM AUTHOR]

Chub mackerel (Scomber japonicus) is a key commercial species in South Korea. However, the catch volume of chub mackerel has experienced significant fluctuations over the past few decades, with current trends indicating a decline. Despite regulatory measures such as closed seasons, resource depletion remains a concern, thereby highlighting the requirement for effective management strategies. Numerous previous studies have proposed optimal harvest strategies by assuming constant prices. However, as large catches of mackerel tend to have lower prices, it is crucial to develop optimal harvest strategies that account for this decrease. Thus, we aim to develop a monthly optimal harvest strategy for chub mackerel that considers catch-dependent pricing. We define logarithmic, rational, and irrational catch-dependent price functions and their corresponding objective functions. In addition, we develop an optimal control system based on a discrete age-structured model. We use Pontryagin's maximum principle to prove the necessary conditions for the optimal harvest strategy under the three catch-dependent pricing functions and perform simulations using the forward–backward sweep method. We compare the optimal harvest strategies under the three catch-dependent pricing scenarios with those under a constant price. The optimal harvest strategies with the rational and irrational price functions are similar to those with a constant price, where the fishing effort increases immediately after spawning and then gradually decreases. In contrast, the optimal harvest strategy with the logarithmic price function involves a gradual increase in fishing effort from July immediately after the spawning period, with the maximum effort in June before the next spawning season. In addition, we compare the effects of monthly closed seasons across the four pricing scenarios. A closed season in July immediately after spawning provides the highest resource recovery efficiency. In contrast, a closed season in June provides the highest catch and profit efficiencies. As the cost per unit of effort increases, the fishing effort, catch, and profit decrease, while the biomass increases, and the profit decrease is smallest under the logarithmic price function. Our method can improve monthly optimal harvest strategies for other species using catch-dependent pricing functions as well as significantly contribute to enhancing fishers' profit. [ABSTRACT FROM AUTHOR]

Access to West Coast and Alaskan fisheries has been progressively tightened for more than four decades with limited license programs, buybacks, and catch share programs. We document the implementation of a series of limited access and catch share programs in federally and state managed fisheries of the West Coast and Alaska, and evaluate trends in participation, diversification, vessel revenue, and variation of revenue between 1981 and 2022 for this large interconnected system of fisheries. Over time, progressive tightening through further input controls, buybacks, and catch shares led to substantial consolidation and greater specialization coinciding with increased temporal diversification, maintained or increased revenue per vessel, and reduced variation in inter-annual revenue. However, low levels of fishery diversification for many fishers, and high dependency on a few key fisheries, may have left fishers vulnerable to ecological and economic shocks that impacted key fisheries leading to increased income variation and further declines in participation in recent years. [ABSTRACT FROM AUTHOR]

By combining acoustic telemetry, mark-and-recapture, and location-specific catch logs, we tested whether angler-fish interactions altered the behavior, space use, and catchability of giant trevally (Caranx ignobilis) (GT) in coastal waters of the Alphonse Island Group, Seychelles, Indian Ocean. Adult GT near a high human use area with limited provisioning showed restricted movements during the tourism fishing season and had home ranges nearly 50% smaller than that of adult GT from other parts of the atoll group. Despite angler catch maps overlapping with 30% of non-habituated adult GT core use areas, recaptures were infrequent, suggesting that GT became hook shy. Although there was no change in movement patterns during a temporary fishing closure caused by COVID-19, non-habituated GT movement patterns shifted toward wider ranging movements with each successive fishing season, potentially to avoid shallow water areas where angler activities occurred. Our findings highlight how angler interactions and catch-and-release fisheries have the potential to modify the behavior, space use, and catchability of targeted species, and may influence the viability of the fishery by exceeding its capacity. [ABSTRACT FROM AUTHOR]

We discuss slip bonds, catch bonds, and the tug-of-war mechanism using mathematical arguments. The aim is to explain the theoretical tool of molecular potential energy surfaces (PESs). For this, we propose simple 2-dimensional surface models to demonstrate how a molecule under an external force behaves. Examples are selectins. Catch bonds, in particular, are explained in more detail, and they are contrasted to slip bonds. We can support special two-dimensional molecular PESs for E- and L-selectin which allow the catch bond property. We demonstrate that Newton trajectories (NT) are powerful tools to describe these phenomena. NTs form the theoretical background of mechanochemistry.