The activation of fibroblast growth factors (FGFs) by glycosaminoglycans: influence of the sulfation pattern on the biological activity of FGF-1

Six synthetic heparin-like oligosaccharides have been used to investigate the effect of the oligosaccharide sulfation pattern on the stimulation of acidic fibroblast growth factor (FGF-1) induced mitogenesis signaling and the biological significance of FGF-1 trans dimerization in the FGF-1 activation process. It has been found that some molecules with a sulfation pattern that does not contain the internal trisaccharide motif, which has been proposed for high affinity for FGF-1, stimulate FGF-1 more efficiently than those with the structure of the regular region of heparin. In contrast to regular region oligosaccharides, in which the sulfate groups are distributed on both sides of their helical three-dimensional structures, the molecules containing this particular sulfation pattern display the sulfate groups only on one side of the helix. These results and the fact that these oligosaccharides do not promote FGF-1 dimerization according to sedimentation-equilibrium analysis, confirm the importance of negative-charge distribution in the activation process and strongly suggest that FGF dimerization is not a general and absolute requirement for biological activity.     

Model for oxygen transfer in rotating biological contactor

Rotating biological contactor is being widely used for wastewater treatment but there is an apparent lack of knowledge about the rate at which oxygen transfer occurs, in physical and biological system. In this study the transfer of oxygen from air to water by a rotating disc air-liquid contactor in physical system is investigated. The oxygen transfer model suggested by Kim and Molof, Water Sci. Technol. 14 (1982) 569, was modified and the developed model is termed as modified Kim and Molof model. The model was calibrated by using available data in literature and validated by experiments conducted in this study. The effect of significant physical parameters was integrated into a single term and is termed as volume renewal number. The modified Kim and Molof model was compared with the other available models. The coefficient of determination (R(2)) for the modified Kim and Molof model obtained is 0.95 which is much higher than in the other available models. Thereby the model is expected to estimate oxygen transfer more accurately. Further, a simplified linear model between K(L)a and the volume renewal number is proposed. Both modified Kim and Molof and linear model estimate the overall oxygen transfer coefficient (K(L)a) accurately.     

Boundary integral equation method to solve embedded planar crack problems under shear loading

The solution of three-dimensional planar cracks under shear loading are investigated by the boundary integral equation method. A system of two hypersingular integral equations of a three-dimensional elastic solid with an embedded planar crack are given. The solution of the boundary integral equations is succeeded taking into consideration an appropriate Gauss quadrature rule for finite part integrals which is suitable for the numerical treatment of any plane crack without a polygonal contour shape and permit the fast convergence for the results. The stress intensity factors at the crack front are calculated in the case of a circular and an elliptic crack and are compared with the analytical solution.     

A method for tracking internal crack propagation in railhead

This paper presents a method for tracking two-dimensional propagation of internal cracks, in particular vertical split head (VSH) defects, due to contact loading in railhead. Generalised curved crack is assumed to have present in the railhead and its propagation is simulated by solving interaction of arbitrary shaped cracks successively. Furthermore, the finite shape of the rail section is also modelled as the continuous distribution of dislocation within an infinite plane. Crack propagation is simulated using the criterion of vanishing of Mode II stress intensity factors (SIF) at crack tips. Examples are provided for tracking the propagation of pre-existing internal cracks in railheads turning into VSH defects under centric contact loading.     

Environmental factors associated with crash-related mortality and injury among taxi drivers in New South Wales, Australia

This exploratory study aims to investigate the associations between some environmental factors and the increased risk of motor vehicle crash-related injuries among taxi drivers. Information utilised in the study are obtained from police reports of all road traffic accidents that occurred on the roads between 1996 and 2000 in New South Wales (NSW), Australia. Of the 7923 taxi drivers who involved in crashes, nearly 10% (n = 750) were killed or injured. Results indicate sex, and two environmental factors are significantly associated with an increased risk of crash-related mortality and injury among taxi drivers. The adjusted relative risk of crash-related mortality and injury is increased by 60% for those who work the night shift (OR = 1.59, 95%CI = 1.35-1.88), and by 20% for those who do not carry any passenger on board (OR = 1.20, 95%CI = 1.02-1.41) should these drivers involve in a crash. The increased relative risk of crash-related mortality and injury is nearly 2.5 times for female taxi drivers (OR = 2.30, 95%CI = 1.45-3.65) when compared with their male counterparts.     

Bayesian spatial and ecological models for small-area accident and injury analysis

In this article, recently developed Bayesian spatial and ecological regression models are applied to analyse small-area variation in accident and injury. This study serves to demonstrate how Bayesian modelling techniques can be implemented to assess potential risk factors measured at group (e.g. area) level. Presented here is a unified modelling framework that enables thorough investigations into associations between injury rates and regional characteristics, residual variation and spatial autocorrelation. Using hospital separation data for 83 local health areas in British Columbia (BC), Canada, in 1990–1999, we explore and examine ecological/contextual determinants of motor vehicle accident injury (MVAI) among male children and youth aged 0–24 and for those of six age groups (<1, 1–4, 5–9, 10–14, 15–19 and 20–24). Eighteen local health area characteristics are studied. They include a broad spectrum of socio-economic indicators, residential environment indicators (roads and parks), medical services availability and utilisation, population health, proportion of recent immigrants, crime rates, rates of speeding charge and rates of seatbelt violation. Our study indicates a large regional variation in MVAI in males aged 0–24 in British Columbia, Canada, in 1990–1999, and that adjusting for appropriate risk factors eliminates nearly all the variation observed. Socio-economic influence on MVAI was profoundly apparent in young males of all ages with the injury being more common in communities of lower socio-economic status. High adult male crime rates were significantly associated with high injury rates of boys aged 1–14. Seatbelt violations and excess speeding charges were found to be positively associated with the injury rates of young men aged 20–24. This and similar ecological studies shed light on reasons for regional variations in accident occurrence as well as in the resulting injuries and hospital utilisation. Thereby they are potentially useful in identifying priority areas for injury/accident prevention and in informing regional health planning and policy development.     

Human factors and folk models

This paper presents a discussion of the susceptibility of human factors to the use of folk models. The case of automation-induced complacency is used as a guiding example to illustrate how folk models (1) substitute one label for another rather than decomposing a large construct into more measurable specifics; (2) are immune to falsification and so resist the most important scientific quality check; and (3) easily get overgeneralised to situations they were never meant to speak about. We then discuss the link between models and measurements, where the model constrains what can be measured by describing what is essential performance, and where the models parameters become the basis for specifying the measurements. We propose that one way forward for human factors is to de-emphasize the focus on inferred and uncertain states of the mind, and shift to characteristics of human performance instead.     

A simulation-based embedded probe technique for human-computer interaction evaluation

There is growing interest in developing video-based methods to evaluate the usefulness and usability of computerised tools in healthcare. In this paper, we propose a human-computer interaction evaluation method that protects the confidentiality of patient information and reduces litigation risks for participants by embedding and analysing performance on probes in complex scenarios with high face validity in a simulated setting. We describe the application of the method to a series of three studies of bar code medication administration (BCMA) software, used to reduce medication errors in the Veterans Administration.     

A theory of emotionally based drive (D) and its relation to performance in simple learning situations.

In a series of experiments at the University of Iowa concerning the role of aversive motivational factors in learning situations, degree of motivation was estimated in terms of "performance on a so-called scale of emotional responsiveness or manifest anxiety." These experiments have aroused considerable and also "not infrequent critical reactions." In part these criticisms "reflect a serious lack of understanding of the structure and purpose of the basic theoretical framework underlying the experiments… . One of the purposes of this paper is to provide a more systematic presentation of our basic theory." A diagram representing a portion of the theoretical schema relevant to data for classical conditioning and specifying classes of independent variables, intervening variables, and dependent variables is provided. "The theory takes its start from Hull's basic assumption that the excitatory potential, E, determining the strength of a response is a multiplicative function of a learning factor, H, and a generalized drive factor, D, i.e., E = H X D." On the basis of analogy with overt reflexes a number of properties that could be assigned to the hypothetical response mechanism proposed are indicated. Experimental evidence relating to the theory is presented and discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality factors in the selection of civilians for isolated northern stations.

An investigation of personality characteristics associated with favorable adjustment to northern isolated living, and the usefulness of psychological tests in the selection of personnel for northern posting. 197 electronic technicians already screened on other psychological tests completed MMPI, Edwards Personal and Brainard Preference tests, and General Information and Arctic Interest questionnaires prior to 1 year of isolation duty on the mid-Canada Line. Adequacy of work and social adjustment was associated with 11 of 35 test variables and 3 of 26 questionnaire items. The discriminating function of the MMPI was reduced by the use of the K correction. It was suggested that despite the highly select nature of the sample used, the test battery has potential value in the selection of civilians to work in the far north.—(17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)