Microbial adhesion to surface-grafted polyacrylamide brushes after long-term exposure to PBS and reconstituted freeze-dried saliva

Polyacrylamide (PAAm) brushes, covalently grafted from silicon wafer surfaces were examined for their ability to inhibit microbial adhesion after long-term exposure to PBS or reconstituted freeze-dried saliva for time intervals from 48 h up to 1 month at 37 degrees C. Microbial adhesion after exposure was studied in a parallel plate flow chamber. Infrared spectra showed that PAAm brushes exhibit good chemical stability upon incubation in both PBS and reconstituted freeze-dried saliva up to 1 month. Reductions in microbial adhesion on PAAm brushes after exposure to PBS or reconstituted freeze-dried saliva varied from 63 to 93% depending on the microbial strain considered, even after 1 month of exposure of the brushes to reconstituted freeze-dried saliva. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 997-1000,2010

Synthesis and characterization of surface-grafted polyacrylamide brushes and their inhibition of microbial adhesion

A method is presented to prevent microbial adhesion to solid surfaces exploiting the unique properties of polymer brushes. Polyacrylamide (PAAm) brushes were grown from silicon wafers by atom transfer radical polymerization (ATRP) using a three-step reaction procedure consisting of immobilization of a coupling agent gamma-aminopropyltriethoxysilane, anchoring of an ATRP initiator 4-(chloromethyl)benzoyl chloride, and controlled radical polymerization of acrylamide. The surfaces were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ellipsometry, and contact-angle measurements. The calculated grafting density pointed to the presence of a dense and homogeneous polymer brush. Initial deposition rates, adhesion after 4 h, and detachment of two bacterial strains (Staphylococcus aureus ATCC 12600 and Streptococcus salivarius GB 24/9) and one yeast strain (Candida albicans GB 1/2) to both PAAm-coated and untreated silicon surfaces were investigated in a parallel plate flow chamber. A high reduction (70-92%) in microbial adhesion to the surface-grafted PAAm brush was observed, as compared with untreated silicon surfaces. Application of the proposed grafting method to silicone rubbers may offer great potential to prevent biomaterials-centered infection of implants.</p

Different virucidal activities of hyperbranched quaternary ammonium coatings on poliovirus and influenza virus

Virucidal activity of immobilized quaternary ammonium compounds (IQACs) coated onto glass and plastic surfaces was tested against enveloped influenza A (H1N1) virus and nonenveloped poliovirus Sabin1. The IQACs tested were virucidal against the influenza virus within 2 min, but no virucidal effect against poliovirus was found in 6 h

Аудит промышленной безопасности организации

Цель выпускной квалификационной работы: Разработка способа быстрого перерасчета пожарного риска для зданий класса функциональной пожарной опасности Ф4.3 офисного типа. В процессе исследования проводилась теоретическая подготовка в исследовании пожарного аудита, анализ литературы в области проведения аудита по пожарной безопасности, разработка способа быстрого перерасчета пожарных рисков на основе "Методика определения расчетных величин пожарного риска в зданиях, сооружениях и строениях различных классов функциональной пожарной опасности".The purpose of the final qualifying work: the Development of a method of rapid recalculation of fire risk for buildings of functional fire hazard class F4.3 office type. In the course of the study, theoretical training was conducted in the study of fire audit, literature analysis in the field of fire safety audit, development of a method for rapid recalculation of fire risks based on the "Method of determining the calculated values of fire risk in buildings, structures and buildings of various classes of functional fire danger"

Microbial biofilm growth vs. tissue integration: "the race for the surface" experimentally studied

Biomaterial-associated infections constitute a major clinical problem. Unfortunately, microorganisms are frequently introduced onto an implant surface during surgery and start the race for the surface before tissue integration can occur. So far, no method has been forwarded to study biofilm formation and tissue integration simultaneously. The aim of this study is to describe an in vitro method to investigate this “race for the surface”. First, a suitable growth medium was prepared that allowed both bacterial and tissue growth in a parallel plate flow chamber. Staphylococci were deposited on the glass bottom plate of the flow chamber in different surface densities, after which U2OS osteosarcoma cells were seeded. U2OS cells did not grow in the absence of flow, possibly due to poisoning by bacterial endotoxins, but under flow both staphylococci and U2OS cells grew. The number of adhering cells and area per spread cell were determined after 48 h in relation to the initial number of bacteria present. Both the number and spread area per cell decreased with increasing density of adhering staphylococci. This demonstrates that the outcome of the race for the surface between bacteria and tissue cells is dependent on the number of bacteria present prior to cell seeding.\u

Innovative Regional Cluster, Model of Tourism Development

AbstractThe cluster is a useful tool for performance companies with a key role in regional development, so it is important to analyze the potential in the tourism sector. Through researches conducted on the competitiveness have been highlighted patterns in tourism and starting from these patterns, the paper identifies a model applicable to South-West Oltenia Region, on the basis of touristic potential, tourism diversity, strengths and weaknesses of the region and the local specificity. This paper aims to find the reason for the formation of clusters of tourism in the region and to develop the main attributes of the cluster, by proposing a conceptual model of cluster innovation, as a catalyst for regional development. The theoretical and methodological approach for this model consists in systematic and comparative analysis of scientific literature regarding the concept and typology of clusters and cluster models applicable in tourism and in the use of methods of analysis of tourist destinations.The competitive advantages of tourism cluster enables orientation of public policies and strategies of tourism competitiveness of private companies and institutions

MODEL OF HEALTH TOURISM DEVELOPMENT - SPA TOURISM CLUSTER IN ROMANIA

Health tourism occupies an important place in the preferences of tourists and represents one of the major sources of revenue for Romania, a country rich in resources spas. Romania holds spas with tourism potential, but which require investments in infrastructure, to work to the standards required of a modern tourism. The need of valorization of balneology potential of the regions to increase regional competitiveness, global and national, has led to the appearance of PPP forms adapted to the particularities of the tourist industry. We develop a collaborative model in which the balneology destinations can become leaders of European health tourism