Background: With the increasing demands for adult orthodontics, a growing need arises to bond attachments to porcelain surfaces. Optimal adhesion to porcelain surface should allow orthodontic treatment without bond failure but not jeopardize porcelain integrity after debonding.The present study was carried out to compare the shear bond strength of metal bracket bonded to porcelain surface prepared by two mechanical treatments and by using different etching systems (Hydrofluoric acid 9% and acidulated phosphate fluoride 1.23%). Materials and Methods: The samples were comprised of 60 models (28mm *15mm*28mm) of metal fused to porcelain (feldspathic porcelain). They were divided as the following: group I (control): the porcelain surface left untreated and glazed, group II (Diamond bur group): the porcelain surface was treated with fine diamond bur at speed of 350000 rpm for 20 seconds, group III (Red stone bur): the porcelain surface was treated with coarse red stone bur at speed of 8500 rpm for 20 seconds. Each group consists of 20 samples, then each group subdivided into two subgroups; one treated with acidulated phosphate fluoride 1.23% and the other subgroup treated with Hydrofluoric acid 9 % with silane coupling agent. Results: The result of this study revealed that there was very high significant difference among all tested groups and the highest shear bond strength was for diamond bur group with HFA and Silane (8.67 MPa), the 2nd highest strength was for control group with HFA and Silane (7.52 MPa), the 3rd was (7.38 MPa) in red stone bur with HFA and Silane, the least shear bond strength values were obtained for subgroups treated with acidulated phosphate fluoride gel 1.23%. Conclusions: The most reliable procedure for bonding orthodontic brackets to the porcelain surfaces is through the surface treatment combinations of mechanical roughening by using diamond bur, 9% Hydrofluoric acid and Silane coupling agent application.
Gas and Downhole Water Sink, Gravity Drainage, GDWS-AGD, Enhance the Recovery of Oil
(4)
A fracture is a damage to bone tissue that causes damage to the tissue surrounding the bone and may penetrate the skin. Subjects and methods: the present study included (80) fractured Iraqi patients (and 40) patients with DM2 and (40) without DM2 and compared them with (40) healthy control. Patients and control are matched in age. This study showed a significant increase in retinol-binding protein 4 (RBP4) and a considerable decrease in Vit .A GPT and GOT in fracture patients with and without DM2. In addition, there was a significant negative correlation between RBP4 with (GPT and GOT) in fracture patients with DM2 and a significant positive correlation between RBP4 with (GPT and GOT) in fracture patients without DM2.
... Show More
Background: Recent research indicates that persistent inflammatory responses may contribute to the rise of diabetic nephropathy (DN) and diabetic cardiovascular disease (DCVD) in type 2 diabetes mellitus patients (DM2). Numerous molecules associated with inflammation and angiogenesis have been implicated in the development and progression of DN and DCVD, respectively. Methods: The subjects were separated into five groups: healthy controls (n= 25), type 2 diabetes mellitus patients (n= 30), type 2 diabetes mellitus patients with nephropathy DN (n= 30), and type 2 diabetes mellitus patients with cardiovascular disease DCVD (n= 30). The blood levels of irisin, IL-8, HbA1C, urea, and creatinine were determined. Results: In current study there w
... Show More
(1)
The study aimed to measure the concentration of some heavy metal elements and represented by (Pb, Cd,Cu) through the use of atomic absorption spectrometer Flame AAS-7000 type SHIMADZU underwent a process modeling to twelve samples from the soil of electricity Dezlat al Jadiriyah station in the Baghdad University compound at a depth of 30-60 cm from the surface and divided the samples into two groups first included six samples from inside the station while the second included six samples from outside the station. For the element of Pb was higher concentration reached by 29.32ppm and less concentration 17.56ppm. were elements Cd and Cu are growing and less and proportions of certain while the highest concentration of copper 9.69 ppm and le
... Show MoreA direct, sensitive and efficient spectrophotometric method for the determination of nitrofurantoin
drug (NIT) in pure as well as in dosage form (capsules) was described. The suggested method was
based on reduction NIT drug using Zn/HCl and then coupling with 3-methyl-2-benzothiazolinone
hydrazone hydrochloride (MBTH) in the presence of ammonium ceric sulfate. Spectrophotometric
measurement was established by recording the absorbance of the green colored product at 610 nm.
Using the optimized reaction conditions, beer’s law was obeyed in the range of 0.5-30 μg/mL, with
good correlation coefficient of 0.9998 and limits of detection and quantitation of 0.163 and 0.544
μg/mL, respectively. The accuracy and
(3)
The importance of the research lies in preparing an experimental curriculum according to a scientific method that will contribute to the development of the special strength(endurance the strength of arms) in order to contribute to the attempt to develop the basic skills of the national team players with the goal ball for the blind As for the research problem, it lies in the weakness of the strength endurance of the national team players with the goal ball for the blind, as the research problem is clearly evident in the last minutes of the match, as well as the former studies in the field of goal ball game for the blind at the country level The research aims to prepare special exercises for endurance of strength as well as t
... Show More
(1)
Species of genus Chrotogonus (surface grasshoppers) are phytophagous and damaging to various economical important plants in their seedling stages. In order to know the biodiversity of surface grasshoppers, the detailed study has been conducted from four provinces of Pakistan. During this study, biodiversity, taxonomy, diagnosis, morphometric analysis, habitat, global distribution, and remarks of each species have been described. Total of 826 specimens were collected and sorted out into three species and three subspecies: C. (Chrotogonus) homalodemus homalodemus (Blanchard, 1836), C. (Chrotogonus) homalodemus (Blanchard, 1836), C. (Chrotogonus) trachypter
... Show More
(3)
(1)
Within the framework of big data, energy issues are highly significant. Despite the significance of energy, theoretical studies focusing primarily on the issue of energy within big data analytics in relation to computational intelligent algorithms are scarce. The purpose of this study is to explore the theoretical aspects of energy issues in big data analytics in relation to computational intelligent algorithms since this is critical in exploring the emperica aspects of big data. In this chapter, we present a theoretical study of energy issues related to applications of computational intelligent algorithms in big data analytics. This work highlights that big data analytics using computational intelligent algorithms generates a very high amo
... Show More
(1)
BP algorithm is the most widely used supervised training algorithms for multi-layered feedforward neural net works. However, BP takes long time to converge and quite sensitive to the initial weights of a network. In this paper, a modified cuckoo search algorithm is used to get the optimal set of initial weights that will be used by BP algorithm. And changing the value of BP learning rate to improve the error convergence. The performance of the proposed hybrid algorithm is compared with the stan dard BP using simple data sets. The simulation result show that the proposed algorithm has improved the BP training in terms of quick convergence of the solution depending on the slope of the error graph.