Background: The development of orthodontic biomaterials that attract less biofilm has been a goal for decades. Adhesion and colonization of cariogenic streptococci are considered to play key roles in the development of enamel demineralization related to orthodontic materials. The aim of this study was to quantitatively evaluate the Mutans streptococci adhesion to coated orthodontic archwires (Epoxy and Teflon) and uncoated archwires (stainless steel and nickel-titanium) with respect to incubation time in the presence and absence of saliva. Material and Method: Six types of archwires stainless steel and nickel titanium with two type of coating (Epoxy, Teflon) were used in this study. Twelve specimens of each archwire were incubated in sterilized unstimulated whole saliva (for the study group) and phosphate-buffered saline (for control group) for 2 hours, then incubated with suspension of Mutans streptococci allowed to adhere for (5,90,180 minutes). Adhesion was quantitated by a microbial culture technique by treating the archwires with adhering bacteria with trypsin and enumerating the colony forming unit (CFU) counts of bacteria recovered after cultivation by using Dentocult SM kit. Results: There was significant difference among the tested archwire types in each time interval with the highest bacterial adhesion on the NiTi archwires in the absence of saliva. In the presence of saliva, the results revealed non-significant difference at 5 min. while there was significant difference at 90 min and highly significant difference at 180 min. Conclusion: The adherence of Mutans streptococci was decreased in the presence of saliva on different archwires and the extended incubation time was significantly related to increase colony forming unit of Mutans Streptococci.
The ability of Cr (VI) removal from aqueous solution using date palm fibers (leef) was investigated .The effects of pH, contact time, sorbets concentration and initial metal ions concentration on the biosorption were investigated.
The residual concentration of Cr (VI) in solution was determined colorimetrically using spectrophotometer at wave length 540 nm .The biosorption was pH-dependent, the optimum pH was 7 and adsorption isotherms obtained fitted well with Langmuir isotherms .The Langmuir equation obtained was Ce/Cs = 79.99 Ce-77.39, the correlation factor was 0.908.These results indicate that date palm fibers (leef) has a potential effect for the uptake of Cr (VI) from industrial waste water.
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Background The traditional management of appendicular mass is an initial conservative treatment followed by interval appendectomy. Recently interval appendicectomy has been questioned.
Objective: The purpose of this study was to clarify the need and the role of interval appendicectomy after successful initial conservative treatment.
Method: This is a prospective study conducted in a major hospital in Basra from April 2006 to Septemper2010, included 65 patients with appendicular mass which subsequently proved postinflammmatory (phlegmonous) changes of the appendix were treated conservatively.
Results: Routine interval appendicectomy was not performed and needed after successful treatment in the majority of the patients (84.6%). F
Melanoides tuberculata (O. F. Müller, 1774), a freshwater snail native to eastern Mediterranean, eastern Africa, southeast Asia, southern Asia, India, and Malaysia, it is an effective invader and is now nearly globally distributed. This snail has been studied with interest because of its rapidly distributed, and because of being can serve as compatible intermediate host for many of trematodes in the world. We have summarized information from many articles in order to highlight the most important aspects of this invader snail life.
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This paper presents a study to investigate the behavior of post-tensioned segmental concrete beams that exposed to high-temperature. The experimental program included fabricating and testing twelve simply supported beams that divided into three groups depending on the number of precasting concrete segments. All specimens were prepared with an identical length of 3150 mm and differed in the number of the incorporated segments of the beam (9, 7, or 5 segments). To simulate the genuine fire disasters, nine out of twelve beams were exposed to a high-temperature flame for one hour. Based on the standard fire curve (ASTM – E119), the temperatures of 300◦C (572◦F), 500◦C (932◦F), and 700◦C (1292◦F) were adopted. Consequently,
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In this work, the switching nonlinear dynamics of a Fabry-Perot etalon are studied. The method used to complete the solution of the differential equations for the nonlinear medium. The Debye relaxation equations solved numerically to predict the behavior of the cavity for modulated input power. The response of the cavity filled with materials of different response time is depicted. For a material with a response time equal to = 50 ns, the cavity switches after about (100 ns). Notice that there is always a finite time delay before the cavity switches. The switch up time is much longer than the cavity build-up time of the corresponding linear cavity which was found to be of the order of a few round-trip ti
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Distributed Denial of Service (DDoS) attacks on Web-based services have grown in both number and sophistication with the rise of advanced wireless technology and modern computing paradigms. Detecting these attacks in the sea of communication packets is very important. There were a lot of DDoS attacks that were directed at the network and transport layers at first. During the past few years, attackers have changed their strategies to try to get into the application layer. The application layer attacks could be more harmful and stealthier because the attack traffic and the normal traffic flows cannot be told apart. Distributed attacks are hard to fight because they can affect real computing resources as well as network bandwidth. DDoS attacks
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