9,641 research outputs found
Traffic Fatalities and Injuries: The Effect of Changes in Infrastructure and Other Trends
No full textAn analysis of how various road infrastructure improvements affect traffic-related fatalities and injuries is conducted while controlling for other factors known to affect overall safety. The road infrastructure elements analysed include total lane miles, the fraction of lane miles in different road categories (interstates, arterial, and collector roads), the average number of lanes for each road category, and lane widths for arterials and collector roads. Other variables that are controlled for in the study include total population, population age cohorts, per capita income, per capita alcohol consumption, seat-belt legislation (and seat-belt usage), and a proxy variable that represents underlying changes in medical technology. The data used is a cross-sectional time series database of U.S. states and is analysed using a fixed effects negative binomial regression that accounts for heterogeneity in the data. Data from all 50 states over 14 years is used. Results strongly refute the hypothesis that infrastructure improvements have been effective at reducing total fatalities and injuries. While controlling for other effects it is found that demographic changes in age cohorts, increased seat-belt use, reduced alcohol consumption and increases in medical technology have accounted for a large share of overall reductions in fatalities.Peer reviewe
Complement’s C1 complex, Factor H and the X factor: A personal tribute to Prof. Robert B. Sim
No full text© 2021 by the author. It is with great sadness that I am writing this obituary for my mentor, colleague and friend, Bob, i.e., Prof. Robert B. Sim, who passed away on 6 February 2021
Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D
No full textSurfactant proteins A (SP-A) and D (SP-D), both members of the collectin family, play a well established role in apoptotic cell recognition and clearance. Recent in vitro data show that SP-A and SP-D interact with apoptotic neutrophils in a distinct manner. SP-A and SP-D bind in a Ca2+-dependent manner to viable and early apoptotic neutrophils whereas the much greater interaction with late apoptotic neutrophils is Ca2+-independent. Cell surface molecules on the apoptotic target cells responsible for these interactions had not been identified and this study was done to find candidate target molecules. Myeloperoxidase (MPO), a specific intracellular defense molecule of neutrophils that becomes exposed on the outside of the cell upon apoptosis, was identified by affinity purification, mass-spectrometry and western blotting as a novel binding molecule for SP-A and SP-D. To confirm its role in recognition, it was shown that purified immobilised MPO binds SP-A and SP-D, and that MPO is surface-exposed on late apoptotic neutrophils. SP-A and SP-D inhibit binding of an anti-MPO monoclonal Ab to late apoptotic cells. Fluorescence microscopy confirmed that anti-MPO mAb and SP-A/SP-D colocalise on late apoptotic neutrophils. Desmoplakin was identified as a further potential ligand for SP-A, and neutrophil defensin as a target for both proteins. <br/
The human lung surfactant proteins A (SP-A) and D (SP-D) interact with apoptotic target cells by different binding mechanisms
No full textThe role of the lung surfactant proteins SP-A and SP-D in immune defence is well established. They bind to foreign organisms that invade the lungs and target them for phagocytic clearance by resident alveolar macrophages. SP-A and SP-D also bind to various apoptotic cells and facilitate their phagocytic uptake. To date, the molecular mechanisms by which the lung surfactant proteins interact with apoptotic cells and phagocytes are poorly understood.The aims of this study were to investigate further the interactions between SP-A and SP-D and apoptotic cells using human neutrophils and Jurkat cells as model systems.Specifically the binding behaviour of SP-A and SP-D with viable, early apoptotic and late apoptotic cells was investigated and compared. SP-A and SP-D show very distinct binding to the various cell types. SP-A bound to viable and early apoptotic cells in a predominantly Ca2+-dependent manner but the interaction with late apoptotic cells was Ca2+-independent, suggesting involvement of other than the lectin- or Ca2+-binding sites. This was consistent for neutrophils and Jurkat cells.SP-D in contrast, did not interact with viable and early apoptotic Jurkat cells but strongly and in a Ca2+-independent manner with late apoptotic Jurkat cells. SP-D-binding to viable and early apoptotic neutrophils was inhibited by maltose and ethylene-diamin-tetra-acetate (EDTA), suggesting lectin-binding site involvement whereas the binding to late apoptotic neutrophils was predominantly Ca2+-independent.These results represent a detailed study of the binding behaviour of SP-A and SP-D with different cell types and stages of viability. The mechanisms of these interactions appear to involve preferential recognition of different ligands on the apoptotic cell surface, which may include nucleic acid, phospholipid, protein and glycan structure
Bikesharing in Philadelphia: do lower-income areas generate trips?
No full textMany bikeshare programs seek to equitably serve residents from different income strata. Experience from other cities in the US and elsewhere in the developed world suggest that bikeshare systems are used mostly by more affluent populations. In order to encourage more bikeshare usage among low-income populations, the City of Philadelphia sited docking stations in low-income neighborhoods, allowed cash payments, and provided discounts to those receiving food-stamps. We examined one-year of data for Philadelphia’s Indego bikeshare system between April 2017 and March 2018. Travel patterns were examined and suggested that bikeshare trips taken from docking stations in lower-income areas are for work commute trips. Multivariate regression models confirmed that lower-income areas generate fewer trips while controlling for other factors such as transit access and whether the station is proximate to a bicycle lane. Our results suggest that despite Indego’s efforts, more work is needed to generate bikeshare trips in lower income neighborhoods.Peer reviewe
From Theory to Practice in Road Safety Policy: Understanding Risk versus Mobility
No full textThis paper reviews theoretical issues surrounding transport safety modeling and the implications for road safety policy. The behavioral mechanisms that affect transport safety are typically not considered in safety modeling. These issues are discussed in the context of trade-offs between risk-taking, as perceived by travelers, and other mobility objectives and the attributes associated with them. This is an extension of other theoretical frameworks, such as risk compensation, and attempts to integrate some of the previous frameworks developed over the years. Various examples of behavioral adaptation to specific policies are discussed and linked to the framework. These issues are then discussed in the context of improvements to empirical work in this area and the linkage of theoretical frameworks to crash modeling, in particular the estimation and use of Crash Modification Factors. Conclusions suggest that there are many deficiencies in practice, from estimation of models to choice of effective policies. Progress is being made on the former, while the publication of practical guidance seems to have substantial lags in knowledge.Peer reviewe
Robert B. Irwin
No full text"Robert Treat Beach is the author of an article in the Montclair Times of October 25, 1932, a fine two-column article entitled 'Robert B. Irwin Has Waged Life-Long Fight to Aid Blind.'
A Tribute to Robert (Bob) Sim—Personal Memories of Working in Bob’s Lab
No full textThis article is intended as a tribute to Robert B. Sim through the sharing of personal memories and anecdotes from two of Bob’s lab members who worked in his lab between 1989 to 1994
A Personal Tribute to Robert B. Sim with Reflections on Our Work Together on Factor H
No full textRobert (Bob) Sim had a profound effect on almost every aspect of my approach to scientific research, acting as a mentor and moral compass through the many different stages of my career [...
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