Fluorescein Redirects a Ruthenium−Octaarginine Conjugate to the Nucleus

The cellular uptake and localization of a Ru−octaarginine conjugate with and without an appended fluorescein are compared. The inherent luminescence of the Ru(II) dipyridophenazine complex allows observation of its uptake without the addition of a fluorophore. Ru−octaarginine−fluorescein stains the cytosol, nuclei, and nucleoli of HeLa cells under conditions where the Ru−octaarginine conjugate without fluorescein shows only punctate cytoplasmic labeling. At higher concentrations, however, Ru−octaarginine without the fluorescein tag does exhibit cytoplasmic, nuclear, and nucleolar staining. Attaching fluorescein to Ru−octaarginine lowers the threshold concentration required for diffuse cytoplasmic labeling and nuclear entry. Hence, the localization of the fluorophore-bound peptide cannot serve as a proxy for that of the free peptide

Statistical theory of correlations in random packings of hard particles

A random packing of hard particles represents a fundamental model for granular matter. Despite its importance, analytical modeling of random packings remains difficult due to the existence of strong correlations which preclude the development of a simple theory. Here, we take inspiration from liquid theories for the $n$-particle angular correlation function to develop a formalism of random packings of hard particles from the bottom-up. A progressive expansion into a shell of particles converges in the large layer limit under a Kirkwood-like approximation of higher-order correlations. We apply the formalism to hard disks and predict the density of two-dimensional random close packing (RCP), $\phi_{\rm rcp} = 0.85\pm0.01$, and random loose packing (RLP), $\phi_{\rm rlp} = 0.67\pm0.01$. Our theory also predicts a phase diagram and angular correlation functions that are in good agreement with experimental and numerical data.Comment: 9 pages, 6 figures, to appear in PR

Exploring the cellular accumulation of metal complexes

Transition metal complexes offer great potential as diagnostic and therapeutic agents, and a growing number of biological applications have been explored. To be effective, these complexes must reach their intended target inside the cell. Here we review the cellular accumulation of metal complexes, including their uptake, localization, and efflux. Metal complexes are taken up inside cells through various mechanisms, including passive diffusion and entry through organic and metal transporters. Emphasis is placed on the methods used to examine cellular accumulation, to identify the mechanism(s) of uptake, and to monitor possible efflux. Conjugation strategies that have been employed to improve the cellular uptake characteristics of metal complexes are also described

Collective Gradient Sensing in Fish Schools

Throughout the animal kingdom, animals frequently benefit from living in groups. Models of collective behaviour show that simple local interactions are sufficient to generate group morphologies found in nature (swarms, flocks and mills). However, individuals also interact with the complex noisy environment in which they live. In this work, we experimentally investigate the group performance in navigating a noisy light gradient of two unrelated freshwater species: golden shiners (Notemigonuscrysoleucas) and rummy nose tetra (Hemigrammus bleheri). We find that tetras outperform shiners due to their innate individual ability to sense the environmental gradient. Using numerical simulations, we examine how group performance depends on the relative weight of social and environmental information. Our results highlight the importance of balancing of social and environmental information to promote optimal group morphologies and performance

MECHANICAL DAMPING SYSTEM FOR STRUCTURES

A mechanical damping system for a structure is provided. The mechanical damping system comprises a tubular impact frame secured to the structure. A support frame is secured to the structure with the support frame spaced from the impact frame. An elongated member is provided having a first end and a second end. The first end is secured within the support frame and the second end is free from connection and extends into the impact frame. At least one impact mass is secured to the second end of the elongated member, the impact mass movable within and contactable with the impact frame

Road User Charging: The Global Relevance of Recent Developments in the United Kingdom

Charging users of the roads for the costs they impose on the system is not new. Economists have been promoting its virtues for as long as arguments about economic efficiency have been in print. What is different today is that a growing number (but by no means all) of decision makers are showing a greater interest and commitment to finding ways to improve the efficiency of the road system, be it through infrastructure expansion and/or other means. Of special interest is the growing level of traffic congestion, and a feeling of almost helplessness, that we seem to have failed in finding a way forward to maintain traffic congestion at levels that are acceptable to the public, and are consistent with principles of good economic practice. The literature abounds with suggestions on how this might be achieved, focused primarily on various pricing regimes that say as much as about levels of charges as they do about the role of the revenue raised, the latter as controversial as the former. The current state of technology provides a capability to introduce sophisticated charging mechanisms. We are at a stage in the evolution of ‘solutions’ to dealing with inefficient road use and provision of road funds that offers real prospects of delivering outcomes that can align with political, social and user demands and expectations. This paper provides a global perspective on the road to efficiency, using the UK contributions in the special issue as a backdrop of what can be done. The issues and challenges are sufficiently global to enable the contributions to be of immediate relevance beyond the UK

Freight Distribution in Urban Areas: The role of supply chain alliances in addressing the challenge of traffic congestion for city logistics

The distribution of freight is a major contributor to the levels of traffic congestion in cities, yet it is much neglected in the research and planning activities of government, where the focus is disproportionately on passenger vehicle movements. Despite the recent recognition of the contribution of freight transportation to the performance of urban areas under the rubric of city logistics, we see a void in the study of how the stakeholders in the supply chain associated with the distribution of goods (whose destination is an urban location) might cooperate through participation in distribution networks, to reduce the costs associated with traffic congestion. Given that transport costs are typically over 45% of all distribution costs, with congestion contributing a substantial amount of cost in the urban setting, the importance of establishing ways in which supply chain partnerships might aid in reducing the levels of freight vehicle movements in urban areas has much merit. This paper sets out a framework to investigate how agents in the supply chain might interact more effectively to reduce their costs of urban freight distribution. We propose an interactive agency choice method as a way of formalising a framework for studying the preferences of participants in the supply chain to support specific policy initiatives. Such a framework is a powerful way of investigating the behavioural response of each agent to many policies including congestion pricing as a way of improving the efficient flow of traffic in cities