3,865 research outputs found
Metabolic changes during carcinogenesis: Potential impact on invasiveness
Successful adaptation to varying microenvironmental constraints plays a crucial role during carcinogenesis. We develop a hybrid cellular automation approach to investigate the cellâmicroenvironmental interactions that mediate somatic evolution of cancer cells. This allows investigation of the hypothesis that regions of premalignant lesions develop a substrate-limited environment as proliferation carries cells away from blood vessels which remain separated by the intact basement membrane. We find that selective forces in tumoural regions furthest from the blood supply act to favour cells whose metabolism is best suited to respond to local changes in oxygen, glucose and pH levels. The model predicts three phases of somatic evolution. Initially, cell survival and proliferation is limited due to diminished oxygen levels. This promotes adaptation to a second phase of growth dominated by cells with constitutively up-regulated glycolysis, less reliant on oxygen for ATP production. Increased glycolysis induces acidification of the local environment, limiting proliferation and inducing cell death through necrosis and apoptosis. This promotes a third phase of cellular evolution, with emergence of phenotypes resistant to acid-induced toxicity. This emergent cellular phenotype has a significant proliferative advantage because it will consistently acidify the local environment in a way that is toxic to its competitors but harmless to itself. The model's results suggest this sequence is essential in the transition from self-limited premalignant growth to invasive cancer, and, therefore, that this transition may be delayed or prevented through novel strategies directed towards interrupting the hypoxiaâglycolysisâacidosis cycle
Support Requirements and Effects of Supervision on Telephone Counsellors
The aim of this research was to examine the effects of the implementation of direct one-on-one supervision in a prominent telephone counselling organization and the support requirements of their telephone counsellors. Ninety-three telephone counsellors participated in this research. The results showed that more experienced telephone counsellors were more satisfied than less experienced telephone counsellors with the support offered by the organization. Furthermore, female telephone counsellors showed significantly more satisfaction with the support offered by the organisation than their male counterparts. Implications of these findings are discussed in relation to the organisation and other helping organisations within the wider community
Determining information for inclusion in a decision-support intervention for clinical trial participation : A modified Delphi approach
Peer reviewedPostprin
Self-Healing Polyphosphonium Ionic Networks
Self healing, ionically crosslinked networks were prepared from poly(acrylic acid) (PAA) and poly(triethyl(4-vinylbenzyl)phosphonium chloride (P-Et-P) and their properties were studied. Three different ratios of PAA/P-Et-P were incorporated into the networks by varying the addition orders of the components. Swelling of the networks increased with increasing NaCl concentration when they were immersed in aqueous solution. All networks retained their structural integrity in 0.1 M NaCl. Studies of the rheological and tensile properties of the networks swelled in 0.1 M NaCl showed that PAA\u3eP-Et-Pexhibited high elongation and viscoelastic properties suitable for self-healing with a relaxation time of ~30 s, whereas the other networks exhibited predominantly elastic behavior. The moduli were similar to those of soft tissues. Self-healing of PAA\u3eP-Et-Pin 0.1 M NaCl was demonstrated through repair of a 0.5 mm diameter puncture in the material whereas healing was incomplete for the other networks and also for PAA\u3eP-Et-Pin the absence of NaCl. Healing after completely severing a tensile testing sample showed significant recovery of the modulus, strength, and elongation. The properties of these materials and their ability to self-heal in low and physiologically relevant salt concentrations make them promising candidates for a variety of applications, particularly in the biomedical area
Effect of counter ions on the self-assembly of polystyrene-polyphosphonium block copolymers
The ability to manipulate block copolymers on the nanoscale has led to many scientific and technological advances. These include nano-scale ordered bulk and thin films and also solution phase components, these are promising materials for making smaller ordered electronics, selective membranes, and also biomedical applications. The ability to manipulate block copolymer material architectures on such small scales has risen from thorough investigations into the properties that affect the architectures. Polyelectrolytes are an important class of polymers that are used to make amphiphilic block copolymers. In this context the authors synthesized polystyrene-b-polyphosphonium block copolymers with different anions coordinated to the polyphosphonium block in order to study the effect of the anion on the aqueous self-assembly of the polymers. The anions play an important role in the solubility of the monomeric materials which results in differences in the self-assembly observed through dynamic light scattering and transmission electron microscopy
Agile methods for agile universities
We explore a term, Agile, that is being used in various workplace settings, including the management of universities. The term may have several related but slightly different meanings. Agile is often used in the context of facilitating more creative problem-solving and advocating for the adoption, design, tailoring and continual updating of more innovative organizational processes. We consider a particular set of meanings of the term from the world of software development. Agile methods were created to address certain problems with the software development process. Many of those problems have interesting analogues in the context of universities, so a reflection on agile methods may be a useful heuristic for generating ideas for enabling universities to be more creative
Antibacterial Activity of Polymers: Discussions on the Nature of Amphiphilic Balance
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The purpose of this Viewpoint is to discuss the molecular design principles that guide development of synthetic antimicrobial polymers, especially those intended to mimic the structure of host defense peptides (HDPs). In particular, we focus on the principle of âamphiphilic balanceâ as it relates to some recently developed polyphosphoniums with somewhat atypical structure. We find that the fundamental concept of amphiphilic balance is still applicable to these new polymers, but that the method to achieve such balance is somewhat unique. We then briefly outline the future challenges and opportunities in this field
Tumorigenic 3T3 cells maintain an alkaline intracellular pH under physiological conditions.
CFS prediction of winter persistent inversions in the Intermountain Region
A recent study by Gillies and others of persistent inversion events in the Intermountain West of the United States found a substantive linkage between the intraseasonal oscillation (ISO) and the development of persistent inversion events. Given that NCEPâs Climate Forecast System (CFS) has demonstrated skill in the prediction of the ISO as far out as 1 month, it was decided to examine the CFS forecastâs capability in the prediction of such winter persistent inversions. After initial analysis, a simple regression scheme is proposed that is coupled to the CFS output of geopotential height as a way to predict the occurrence of persistent inversion events for Salt Lake City, Utah. Analysis of the CFS hindcasts through the period 1981â2008 indicates that the regression coupled with the CFS can predict persistent inversion events with lead times of up to 4 weeks. The adoption of this coupled regressionâCFS prediction may improve the forecasting of persistent inversion events in the Intermountain West, which is currently restricted to the more limited time span (;10 days) of medium-range weather forecast models
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