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Hyaluronan and proximal tubular cell migration
No full textBackground The ubiquitous polysaccharide hyaluronan has been associated with both acute renal injury and progressive renal disease. The aim of this study was to examine the effect of hyaluronan on proximal tubular cell migration.
Methods The proximal tubular cell line, HK-2 cells, were grown in monolayer culture, and cell migration following addition of hyaluronan characterized in an in vitro model of injury that we have previously developed and characterized.
Results Addition of well-defined preparations of exogenous hyaluronan increased cell migration; however, optimum enhancement of migration was seen with hyaluronan of high molecular weight. Activation of the mitogen-activated protein kinase (MAPK) signaling cascade, as assessed by increased expression of the dually phosphorylated active form of MAPK, could be demonstrated following addition of hyaluronan. This was blocked by the addition of a specific antibody to the hyaluronan receptor, CD44. Hyaluronan-dependent enhanced migration was also abrogated by addition the CD44 blocking antibody, and by inhibition of MAPK kinase (MEK) activity. Generation of a denuded area also led to increased synthesis of endogenous hyaluronan and activation of MAPK, and blockage of either CD44 or MAPK activation inhibited proximal tubule cell (PTC) migration and re-epithelialization under nonstimulated conditions.
Conclusion We have demonstrated that hyaluronan activation of the MAPK pathway through binding to its receptor CD44, enhances proximal tubule cell (PTC) migration. In addition, the results suggest that mechanical injury of PTC stimulated hyaluronan generation. These observations may have implications for both recovery from acute tubular injury and progressive renal fibrosis
User Modelling in Ambient Intelligence for Elderly and Disabled People
No full textCombining ongoing Ambient Intelligence (AmI) technological developments (e.g. pervasive computing, wearable devices, sensor networks etc.) with user-centred design methods greatly increases the acceptance of the intelligent system and makes it more capable of providing a better quality of life in a non-intrusive way. Elderly people could clearly benefit from this concept. Thanks to smart environments, they can experience considerable enhancements, giving them an opportunity to live more independently and for longer in their home rather than in a health-care centre. However, to implement such a system, it is essential to know for whom we are designing. In this paper, we present an intelligent system with a monitoring infrastructure that will help mainly elderly users with impairments to overcome their handicap. The purpose of such a system is to create a safe and intuitive environment that will facilitate the achievement of household tasks in order to preserve independence of elderly residents for a while longer. Pursuing this goal, we propose to use the persona concept to help us build a user model based on the personas’ aptitudes. The practice of user modelling emphasizes the importance of user-centred techniques in any AmI system development and highlights the potential impacts of AmI for certain targeted groups - in this case, the elderly and people with disabilities
Experimental and Theoretical Investigation into the Formation and Reactivity of M(Cp)(CO)₂(CO₂) (M = Mn or Re) in Liquid and Supercritical CO₂ and the Effect of Different CO₂ Coordination Modes on Reaction Rates with CO, H₂, and N₂
No full textNanosecond time-resolved infrared spectroscopy (TRIR) has been used to study the coordination of CO₂ to the metal centers by UV photolysis of M(Cp)(CO)₃ (M = Mn or Re) in liquid or supercritical CO₂ (scCO₂) solution, which led to the formation of the CO₂ complexes M(Cp)(CO)₂(CO₂). Differences between the positions of the ν(C−O) IR bands of the CO ligands in Mn(Cp)(CO)₂(CO₂) and Re(Cp)(CO)₂(CO₂) suggest that the CO₂ ligand has different coordination modes to the metal centers in these complexes. The kinetic data and the IR spectra of the CO₂, Xe, and heptane complexes provided evidence that the CO₂ coordination mode is η¹-O end-on bound in Mn(Cp)(CO)₂(CO₂), and η²-C,O side-on bound in Re(Cp)(CO)₂(CO₂). These different coordination modes lead to dramatic differences in reactivity with CO, H₂, and N₂, with the Re complexes being significantly less reactive. To provide more evidence for the nature of the CO₂ binding modes, a series of DFT calculations were performed at the B3LYP/SDD-6-311G** level. The calculations supported the experimentally proposed CO₂ coordination modes. A significant charge transfer from Re to CO₂ occurs, resulting in partial oxidation of Re
QoS Analysis Models for Wireless Networks
Get PDFGuaranteeing of QoS over wireless networks is a very challenging task. The first and critical step in addressing this problem is to build up a QoS analysis model which accurately characterizes the fading channel and time-varying capacity of the link, by quantifying parameters like Bit Error Rate (BER) or delay to protocols of higher layers. This paper presents a study of QoS models from a physical and data link layer point of view, more specifically, we introduce the Finite State Markov Chain (FSMC) model for fading channels at the physical layer and the Effective Capacity (EC) model at the data link layer. The FSMC can provide us with a quick estimate of current channel conditions like BER, while it is very hard using the physical channel model to get parameters like delay which needs an analysis of queueing behaviors; for that reason, a link-layer model – EC which provides a statistical QoS model on the unacceptable delay performance (i.e., the probability of delay exceeds a bound) is then studied. The characteristics, advantages and disadvantages of these two models will be studied and compared in this paper
Spanning Tree Objective Functions and Algorithms for Wireless Networks
Get PDFThis paper considers various forms of objective function that may be applied in the calculation of spanning trees in different network situations. Conventional link and path cost approaches are compared to those based on switch or bridge costs more appropriate for wireless applications. Variant objectives are formulated and compared. Although efficient exact algorithmic approaches exist only for the link cost objectives, reasonable approximations for the switch/bridge equivalents are to be found with simple greedy heuristics and better results still through various forms of iterated local search such as tabu search and simulated annealing
Inhibition of Protein Adsorption onto Silica by Polyvinylpyrrolidone
No full textIsotherms for the adsorption of poly(vinylpyrrolidone) (PVP) and bovine serum albumin (BSA) onto silica have been determined. The adsorption capacity for PVP increased with increasing molecular mass but was independent of pH and ionic strength. The adsorbed layer thickness, δ, was determined from ζ potential measurements. δ was found to increase with increasing surface coverage but was significantly less than the polymer radius of gyration even at the adsorption plateau, indicating that the polymer coils flattened at the surface. BSA did not adsorb onto silica from water at pH 7 because of electrostatic repulsions, but adsorption did occur in the presence of electrolyte. The amount of BSA adsorbed at plateau coverage increased from 0.1 mg/m2 in 0.001 M NaCl to 1.0 mg/m2 in 0.5 M NaCl. BSA adsorption was significantly inhibited but not completely prevented, by precoating the silica particles with PVP. Even at low PVP surface coverages, where δ had very low values, some inhibition occurred. Furthermore, PVP was able to desorb most but not all BSA molecules from the silica particles
Semi-Active Suspension System Simulation Using SIMULINK
Get PDFThis paper describes a simulation design procedure aimed to achieve improved performance of the vehicle semi-active suspension. The issues related to the design of vehicle models with skyhook control are discussed. Three basic models with linear parameters are explained: quarter-, half- and full-car. The road profile is generated from a spatial power spectral density (PSD) to represent a typical road (based on ISO 8608 classification). The normalized root-mean-square values of sprung mass acceleration and tyre load forces are used to assess the vehicle ride comfort and handling performance based on five benchmark road profiles employed in industrial tests
The War on Drugs – A War on Drug Users
Get PDFThe authors argue that since the 1980s UK drug policy has largely been ill considered, reactive and counter- productive. Rather than reducing drug taking and drug related crime, such policies have exacerbated the problem and contributed towards an environment in which drug use and illegal drug activities are likely to flourish. One of the consequences of this 'war on drugs' is that it manifests itself as a 'war on drug users' with an emphasis not upon the development of appropriate rehabilitative models, but upon prevention, prohibition and punishment. Drawing on the authors' qualitative research on Merseyside, England involving 200 problem drug users, it will be argued that the war on drug users has subjected these people to a process of stigmatization, marginalization and social exclusion, and prevented many of them from recovery by hindering their re-integation into the wider social and economic community. Instead, growing numbers of problematic drug users remain locked into a cycle of chronic drug relapse
Temporal stability of the Francis Scale of Attitude Toward Christianity among 9- to 11-year-old English children: Test-retest data over six weeks
No full textRecently two studies have reported on the test-retest reliability of the Francis Scale of Attitude toward Christianity; however, these studies were limited to samples of university students. This study examined the temporal stability of both the 24- and 7-item versions of the junior version of the Francis Scale of Attitude toward Christianity (Francis, 1978; Francis, Greer, & Gibson, 1991) over a six-week period among a sample of 58 English children aged between 9 and 11 years old. Data demonstrated that stability across the two administrations was very high for both the 24- (r=.74) and 7-item (r=.67) versions, and there was no significant change between Time 1 and Time 2 for either version. These data support the short-term test-retest reliability of both the 24- and 7-item versions of the junior version of the Francis Scale of Attitude toward Christianity among children