Background: The demand for better esthetic during orthodontic treatment has increased nowadays, so orthodontists starting using esthetic arch wires, brackets and ligatures.Tooth colored brackets were introduced in different types of materials. Sapphire ceramic brackets are one type of esthetic brackets and their color stability remains the main concern for the clinicians and patients at the same time. The present study design to evaluate the effect of three different staining materials (pepsi, black tea and cigarette smoke) on the stainability of sapphire ceramic brackets bonded with three types of light cure orthodontic adhesives which include: Resilience, Enlight and Transbond. Materials and Methods: The sample consisted of three hundred sixty sapphire brackets. The brackets were divided according to bonding materials into three groups each group consist of one hundred twenty brackets, then each subgroup farther subdivided into four groups according to the material they were immersed (distilled water, black tea, Pepsi and cigarette smoke) with thirty brackets each, then Each group with ten brackets farther subdivided according to time interval of immersion in each media into three groups one day, seven days and fourteen days at 37°C in the incubator.A UV-Visible spectrophotometer (Shimadzu, UV -1800) was used to perform a light absorption test. Results: ANOVA and LSD post Hoc tests were used to identify the significant effects of the staining materials at a significance level P ≤ 0.05.It was found that the immersion time gradually influenced the color stability of the adhesive materials with sapphire brackets with the highest activity observed at fourteen days interval. The brackets bonded with Resilience light cure adhesive are the most type affected by staining materials, then followed by the brackets bonded with Transbond and finally the brackets bonded with Enlight light cure adhesive. For the staining materials it was found that the cigarette smoke is the most powerful staining material, followed by tea and finally pepsi. Conclusions: From the above result we can conclude that the type of adhesive must take in consideration when the esthetic brackets have been used.
The thermal performance of a flat-plate solar collector (FPSC) using novel heat transfer fluids of aqueous colloidal dispersions of covalently functionalized multi-walled carbon nanotubes with β-Alanine (Ala-MWCNTs) has been studied. Multi-walled carbon nanotubes (MWCNTs) with outside diameters of (< 8 nm) and (20–30 nm) having specific surface areas (SSAs) of (500 m2/g) and (110 m2/g), respectively, were utilized. For each Ala-MWCNTs, waterbased nanofluids were synthesized using weight concentrations of 0.025%, 0.05%, 0.075%, and 0.1%. A MATLAB code was built and a test rig was designed and developed. Heat flux intensities of 600, 800, and 1000 W/m2; mass flow rates of 0.6, 1.0, and 1.4 kg/min; and inlet fluid temperatures of 30, 40, an
... Show MoreThis study was designed to determine the percentage and the main causative agent causing bacteremia among children aged up to 12 years and complaining from different types of infections (Respiratory, intestinal, and urinary tract infection) in Baghdad. Results showed that the percentage of infection was 46.19 % the main causative agents were Enterobacteriaceae including (E.coli , Pseudomonas , Salmonella.typhi .Serratia , Enterobacter , Klebsiella )and other than Enterobacteriaceae which includes(Staph.aureus , Staph.epidermidis , Streptococcus.Pneumonia and ?-hemolytic streptococci ) .Regarding the age factor ,results showed that the highest infection rate was among the age group (1 day-12 month ) and (12 -36month ) (64.89%)an
... Show MoreThis study was designed for isolation and molecular identification of Nontuberculous Mycobacterium (NTM) from fish during the period between October and December 2017 from Karbla province, Iraq. This study included 200 fresh fish samples from four different species including Spondyliosoma cantharus, Liza abu, Carassius carassius and Cyprinuscarpio. Three samples of each fish were taken including gills, muscles and all internal organs. The samples were processed by decontamination, concentration of 4% sodium hydroxide, and 0.1 ml of sediment was streaking on Löwenstein Johnson (LJ) media; then the bacterial cultures were incubated at 28-30 °C for 3days up to 4 weeks and suspected colonies were stained with acid fast stain to confir
... Show MoreABSTRACT
Naproxen(NPX) imprinted liquid electrodes of polymers are built using polymerization precipitation. The molecularly imprinted (MIP) and non imprinted (NIP) polymers were synthesized using NPX as a template. In the polymerization precipitation involved, styrene(STY) was used as monomer, N,N-methylenediacrylamide (N,N-MDAM) as a cross-linker and benzoyl peroxide (BPO) as an initiator. The molecularly imprinted membranes and the non-imprinted membranes were prepared using acetophenone(AOPH) and di octylphathalate(DOP)as plasticizers in PVC matrix. The slopes and detection limits of the liquid electrodes ranged from)-18.1,-17.72 (mV/decade and )4.0 x 10-
... Show MoreIn wide range of chemical, petrochemical and energy processes, it is not possible to manage without slurry bubble column reactors. In this investigation, time average local gas holdup was recorded for three different height to diameter (H/D) ratios 3, 4 and 5 in 18" diameter slurry bubble column. Air-water-glass beads system was used with superficial velocity up to 0.24 m/s. the gas holdup was measured using 4-tips optical fiber probe technique. The results show that the axial gas holdup increases almost linearly with the superficial gas velocity in 0.08 m/s and levels off with a further increase of velocity. A comparison of the present data with those reported for other slurry bubble column having diameters larger than
... Show MoreThe compound chalcon originally is extracted form some plant and herbs, the studies of the antiviral activity of this compound were done in two cell line cultures the L2OB and RD, the compound relatively non toxic to both cell lines of the concentration of 32?g/ml or less ,the compound have significantly anti poliovirus activity in both L2OB cell line and RD cell line, we find that the concentration of 0.03 ?g/ml or more inhibit the 100TCDID50 of the poliovirus .The therapeutic index(TI)used in this study to evaluate the drug activity ,( TI is the ratio of dose of drug which is just toxic to the cells to the does which is just inhibit the viral multiplication, if this index more than one the margin of safety of drug is according great ) .In
... Show MoreThe study aims to introduce the Islamic sites available on the Internet and determine the criteria that contribute to evaluating these sites to indicate their value, topics, and services, while evaluating a simple random sample of the general Islamic sites, which number (35) sites. The results were presented in (8) tables. The study concluded To a set of conclusions, including: (465) “Islamic” websites were seized during the research period, and they are constantly increasing. They were classified according to the name of the website (domain name) com, org, net, edu, and also according to topics such as general Islamic websites and websites of holy places. Mosques, sites of sheikhs, etc. Among the best general Islamic websites are: Isla
... Show MoreThe interplay of predation, competition between species and harvesting is one of the most critical aspects of the environment. This paper involves exploring the dynamics of four species' interactions. The system includes two competitive prey and two predators; the first prey is preyed on by the first predator, with the former representing an additional food source for the latter. While the second prey is not exposed to predation but rather is exposed to the harvest. The existence of possible equilibria is found. Conditions of local and global stability for the equilibria are derived. To corroborate our findings, we constructed time series to illustrate the existence and the stability of equilibria numerically by varying the different values
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