The demand for public transport: The effects of fares, quality of service, income and car ownership

This paper reports on key findings from a collaborative study whose objective was to produce an up-to-date guidance manual on the factors affecting the demand for public transport for use by public transport operators and planning authorities, and for academics and other researchers. Whilst a wide range of factors was examined in the study, the paper concentrates on the findings regarding the influence of fares, quality of service and income and car ownership. The results are a distillation and synthesis of identified published and unpublished information on the factors affecting public transport demand. The context is principally that of urban surface transport in Great Britain, but extensive use was made in the study of international sources and examples

Standard electrode potentials involving radicals in aqueous solution: inorganic radicals

Inorganic radicals, such as superoxide and hydroxyl, play an important role in biology. Their tendency to oxidize or to reduce other compounds has been studied by pulse radiolysis; electrode potentials can be derived when equilibrium is established with a well-known reference compound. An IUPAC Task Group has evaluated the literature and produced the recommended standard electrode potentials for such couples as (O2/O2·-), (HO·, H+/H2O), (O3/O3·-), (Cl2/Cl2·-), (Br2·-/2Br-), (NO2·/NO2-), and (CO3·-/CO32-

Biologically Relevant Small Radicals

Biologically relevant small radicals are at the focus of the working group 4 (WG4) of the COST Action CM0603 (Free Radicals in Chemical Biology, CHEMBIORADICAL). This article surveys the areas of research being undertaken by the partners in WG4. The character of the radicals is described together with experimental techniques utilized to follow their structure and reactivity. Specifically, C-, S-, N- and O-centered radicals of small size, and their interaction with different biomolecules are described. Processes at the molecular level exemplifying important biological signaling and damaging pathways are introduced

New appraisal values of travel time saving and reliability in Great Britain

© 2017, The Author(s). This paper provides an overview of the study ‘Provision of market research for value of time savings and reliability’ undertaken by the Arup/ITS Leeds/Accent consortium for the UK Department for Transport (DfT). The paper summarises recommendations for revised national average values of in-vehicle travel time savings, reliability and time-related quality (e.g. crowding and congestion), which were developed using willingness-to-pay (WTP) methods, for a range of modes, and covering both business and non-work travel purposes. The paper examines variation in these values by characteristics of the traveller and trip, and offers insights into the uncertainties around the values, especially through the calculation of confidence intervals. With regards to non-work, our recommendations entail an increase of around 50% in values for commute, but a reduction of around 25% for other non-work—relative to previous DfT ‘WebTAG’ guidance. With regards to business, our recommendations are based on WTP, and thus represent a methodological shift away from the cost saving approach (CSA) traditionally used in WebTAG. These WTP-based business values show marked variation by distance; for trips of less than 20miles, values are around 75% lower than previous WebTAG values; for trips of around 100miles, WTP-based values are comparable to previous WebTAG; and for longer trips still, WTP-based values exceed those previously in WebTAG

Controlling the rates of reductively-activated elimination from the (indol-3-yl)methyl position of indolequinones

A series of substituted 3-(4-nitrophenyloxy)methylindole-4,7-diones (Q) were synthesised. The effects of substitution patterns on the indole core on rates of elimination of 4-nitrophenol as a model for drug release following fragmentation of a phenolic ether linker were studied. After reduction to either the radical anion (Q ؒϪ ) or hydroquinone (QH 2 ) elimination of 4-nitrophenol occurred from the (indol-3-yl)methyl position. The half-lives , typical of tumour hypoxia, were t1 -2 ≈ 0.3-1.8 ms, the higher values associated with higher reduction potentials. Half-lives for the autoxidation of the QH 2 were markedly longer at the same oxygen concentration (t1 -2 ≈ 8-102 min) and longer still in the presence of 4 µmol dm Ϫ3 superoxide dismutase (t1 -2 ≈ 8-19 h). Although the indolequinones were able to eliminate 4-nitrophenol with high efficiency only Q ؒϪ radicals of the 3-carbinyl substituted derivatives did so with sufficiently short half-lives (t1 -2 ≈ 41-2 ms) to compete with electron transfer to oxygen and therefore have the potential to target the leaving group to hypoxic tissue. The hydroquinones are not sufficiently oxygen sensitive to prevent the elimination of 4-nitrophenol (t1 -2 ≈ 1.5-3.5 s) even at oxygen concentrations expected in normal tissue. By incorporating electron rich substituents at the indolyl carbinyl position it is possible to control the rate of reductive fragmentation. This may prove an important factor in the design of an indolequinone-based bioreductive drug delivery system

Imaging the boundaries—innovative tools for microscopy of living cells and real-time imaging

Recently, light microscopy moved back into the spotlight, which is mainly due to the development of revolutionary technologies for imaging real-time events in living cells. It is truly fascinating to see enzymes “at work” and optically acquired images certainly help us to understand biological processes better than any abstract measurements. This review aims to point out elegant examples of recent cell-biological imaging applications that have been developed with a chemical approach. The discussed technologies include nanoscale fluorescence microscopy, imaging of model membranes, automated high-throughput microscopy control and analysis, and fluorescent probes with a special focus on visualizing enzyme activity, free radicals, and protein–protein interaction designed for use in living cells

Radiation chemistry comes before radiation biology.

PURPOSE: This article seeks to illustrate some contributions of radiation chemistry to radiobiology and related science, and to draw attention to examples where radiation chemistry is central to our knowledge of specific aspects. Radiation chemistry is a mature branch of radiation science which is continually evolving and finding wider applications. This is particularly apparent in the study of the roles of free radicals in biology generally, and radiation biology specifically. The chemical viewpoint helps unite the spatial and temporal insight coming from radiation physics with the diversity of biological responses. While historically, the main application of radiation chemistry of relevance to radiation biology has been investigations of the free-radical processes leading to radiation-induced DNA damage and its chemical characterization, two features of radiation chemistry point to its wider importance. First, its emphasis on quantification and characterization at the molecular level helps provide links between DNA damage, biochemical repair processes, and mutagenicity and radiosensitivity. Second, its central pillar of chemical kinetics aids understanding of the roles of 'reactive oxygen species' in cell signalling and diverse biological effects more generally, and application of radiation chemistry in the development of drugs to enhance radiotherapy and as hypoxia-specific cytotoxins or diagnostic agents. The illustrations of the broader applications of radiation chemistry in this article focus on their relevance to radiation biology and demonstrate the importance of synergy in the radiation sciences. CONCLUSIONS: The past contributions of radiation chemistry to radiation biology are evident, but there remains considerable potential to help advance future biological understanding using the knowledge and techniques of radiation chemistry