Staphylococcus aureus is a common pathogenic agent due to its ability to cause various types of infections, ranging from mild skin infections to sever systemic diseases. One of the most virulence factors of this bacterium is its ability to from biofilms on solid surfaces by anchoring the planktonic cells and by producing a protective layer of extra polymeric substances. Biofilm formation is controlled through many genes. The most important ones are icaA and icaD. Dentures are prosthetic devices that are made of different materials to replace lost teeth. The aim of this study is to examine the ability of different types of denture materials to support the biofilm formation of S. aureus at phenotypic level by detecting bacterial growth on them using crystal violet and scanning electron microscope, as well as genotypic level through detection and estimation of gene icaA and icaD expression. Our findings showed that the denture materials do support biofilm formation and there is elevation in gene expression of icaA and icaD.
We report a method of converting non-conductive plastic surfaces into conductive by plating either copper electroless or copper electroplating -carbon black containing bending Agent onto Perspex plastics . Various approaches have been studied in order to comparing properties of the plated copper for two methods such as scanning electron microscopy (SEM),thickness, roughness, porosity, tensile Strength and elongation. The results show that the surface of electroplating was uniform, compact, and continuous and it had an obvious metallic sheen, while the surface of plated copper for electroless for it had many pores. Also observed that the coating was composed of small cells. Thes
... Show MoreAbstract. Froth flotation is a solid-liquid separation technique that uses hydrophobicity as a driving force. Bacteria and other drinking water microorganisms tend to be hydrophobic and can be removed from water using this application. The biggest limitation against using froth flotation in the drinking water industry is the difficulty of producing froth without chemical frothers and holding bacteria in this froth without chemical collectors which deteriorate water taste and odor. Recently, researchers at the University of Sheffield described a method for producing froth using only water and compressed air. This has enabled froth flotation to be studied as an alternative to biocides for the removal of bacteria from drinking water. T
... Show MoreIn this research the subject of human ability to change, as it is proven in the Koran , which is proof of the argument against the ability of human change , whether the change in the positive or negative direction .
Here the limits of the research are limited to a study of analysis of human ability to change and this establishes the important of knowing that man has the ability while in the wrong way to change the path to the right path which Gifts and guidance .
The search required three demands and conclusion
- The first required :- is to try the idolaters to take out believers by right .
- The second required :- is to change what is inside the soul as a reason to enter blessings on man .
- The third required :- is good
Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time
... Show MoreBackground: One of the most common complications of dentures is its ability to fracture, so the aim of this study was to reinforce the high impact denture base with carbon nanotubes in different concentrations to improve the mechanical and physical properties of the denture base. Materials and methods: Three concentrations of carbon nanotubes was used 0.5%, 1%, 1.5% in a pilot study to see the best values regarding transverse strength, impact, hardness and roughness test, 1 wt% was the best concentration, so new samples for control group and 1wt% carbon nanotubes and the previous tests were of course repeated. Results: There was a significant increase in impact strength and transverse strength when we add carbon nanotubes in 1wt%, compared
... Show MoreThe increasing use of antiseptic compounds creates selective pressure cause emergence of antiseptic resistance among Staphylococcus aureus .Resistance mechanism of antiseptic is driven mainly by multi drug resistant (MDR) efflux protein.Sixty five isolates of S.aureuswere collected from different clinical sources and subjected to 11 antibiotics most of them are recognized by efflux systems as extruded substrates. Range of efflux activity was estimated using cartwheel method. Simultaneous discrimination of antiseptic coding genes (qacA/B, smr and norA)as well as nuc and mecA genes among multidrug resistantS.aureus(MRSA) isolates was preformed using multiplex PCR assay
... Show MoreBackground: The combination of thermoplastic nylon resin materials and auto polymerizing resin is necessary in some situation for repair and adjustment. This study evaluated shear bond strength between thermoplastic nylon material (flexible) and auto polymerizing acrylic resin subjected to holes and silica coated layer. Materials and Method: Forty five (45) specimens were prepared from flexible acrylic bonded to auto-polymerizing acrylic resin and divided into three groups according to the surface treatments as follows: Group A: 15 specimens of flexible acrylic bonded with cold-cure acrylic by holes. Group B: 15 specimens of flexible acrylic bonded with cold-cure acrylic by silica coated layer. Group C: 15 specimens of flexible acrylic bon
... Show MoreThe term of ability (Al qoudra) is of the common terms which used by speech scientists to relate to one of the important verbal issues which called “Fate and destiny”. the issues of fate and destiny has been raised by Muslims since the dawn of Islam and It was researched among speech scientists, there are many opinions about this issues as the man can do or leave anything or he forced to do something that mean he hasn’t ability.
Also the term was used by jurists and they mention to the ability conditions (Assigning the Divine) and when this conditions are not available that means the man is not commissioning, the conditions are Mind, puberty and other conditions which mentioned in the books of jurisp
... Show MoreHot-wire cutting is one of the important, non-traditional thermomechanical way to cut polymer, usually expanded foam and extruded foam, in low volume manufacturing. The study and analysis of Hot-Wire cutting parameters play an important role to enhance the quality and accuracy of the process and products. The effects on the surface have been investigated by using experimental tests designed according to the Taguchi orthogonal array (OA). In this study, four parameters with five levels for each parameter have been used: [temperature of wire (A) (100, 120, 130, 150, 160) °C], [diameter of wire (B) (0.3,0.4,0.5,0.7,0.8) mm], [velocity of cutting (C) (200, 300,400,500,600) mm/min], [and density of foam (D) (0.01,0.0
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