2 resultados para biological and biochemical activities

em Brock University, Canada


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In 2009, the Ontario Government closed the last three remaining large-scale institutions for people with Developmental Disabilities (DD). The purpose of this study is to examine the community-based recreation and leisure activities of 87 adults with DD who have recently moved into the community. Study 1 provided a descriptive insight into the community recreation and leisure activities, and revealed that people with DD engage in low levels of community activities, however are reported to have the desire to engage more often. Staff reported that people with DD do not have the opportunities to engage in their preferable activities. Study 2 investigated the prbspective predictors of the number and frequency of community, recreation and leisure activities and found that a higher level of functioning predicted a greater number of community activities ([beta] = .26, P < .05), while both a higher level of functioning ([beta] = .38,p < .001) and greater preference ([beta] = .23. p < .05) predicted more frequent access to community activities. Future research and the implications of the findings for clinical practice and policy development were discussed.

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Chlorhexidine is an effective antiseptic used widely in disinfecting products (hand soap), oral products (mouthwash), and is known to have potential applications in the textile industry. Chlorhexidine has been studied extensively through a biological and biochemical lens, showing evidence that it attacks the semipermeable membrane in bacterial cells. Although extremely lethal to bacterial cells, the present understanding of the exact mode of action of chlorhexidine is incomplete. A biophysical approach has been taken to investigate the potential location of chlorhexidine in the lipid bilayer. Deuterium nuclear magnetic resonance was used to characterize the molecular arrangement of mixed phospholipid/drug formulations. Powder spectra were analyzed using the de-Pake-ing technique, a method capable of extracting both the orientation distribution and the anisotropy distribution functions simultaneously. The results from samples of protonated phospholipids mixed with deuterium-labelled chlorhexidine are compared to those from samples of deuterated phospholipids and protonated chlorhexidine to determine its location in the lipid bilayer. A series of neutron scattering experiments were also conducted to study the biophysical interaction of chlorhexidine with a model phospholipid membrane of DMPC, a common saturated lipid found in bacterial cell membranes. The results found the hexamethylene linker to be located at the depth of the glycerol/phosphate region of the lipid bilayer. As drug concentration was increased in samples, a dramatic decrease in bilayer thickness was observed. Differential scanning calorimetry experiments have revealed a depression of the DMPC bilayer gel-to-lamellar phase transition temperature with an increasing drug concentration. The enthalpy of the transition remained the same for all drug concentrations, indicating a strictly drug/headgroup interaction, thus supporting the proposed location of chlorhexidine. In combination, these results lead to the hypothesis that the drug is folded approximately in half on its hexamethylene linker, with the hydrophobic linker at the depth of the glycerol/phosphate region of the lipid bilayer and the hydrophilic chlorophenyl groups located at the lipid headgroup. This arrangement seems to suggest that the drug molecule acts as a wedge to disrupt the bilayer. In vivo, this should make the cell membrane leaky, which is in agreement with a wide range of bacteriological observations.