Background: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500˚C for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves samples that were polished using (karat diamond polishing set, Vita zahnfabrik, Germany), group II involves samples that were polished with (zirconia polishing kit, SMEdent, Shanghai, China), group III involves samples that were polished with (OptraFine® diamond polishing system, Ivoclar Vivadent, Germany), while group IV involves samples that were glazed using glazing medium (VITA Akzent Glaze AKZ 25, Vita zahnfabrik, Germany). Surface roughness values (Ra) (in µm) of all the specimens were recorded at each stage of surface treatment of zirconia disks (leveling and finishing, adjustment of the samples and polishing / glazing) using surface roughness tester. Statistical analysis was carried out using one-way ANOVA and LSD tests. Results: The results showed that the glazing group recorded the lowest surface roughness mean value, followed by (OptraFine® polishing system), then (zirconia polishing kit) and finally (karat polishing set) which showed the highest mean of surface roughness. For all groups, there was a statistically very high significant difference of (Ra) value before and after adjustment of the samples. Moreover, there was a statistically very high significant difference in (Ra) value when comparing the adjusted samples with the polished and glazed ones. Karat polishing set group showed a statistically highly significant difference with zirconia polishing kit group (P<0.01). Both, karat polishing set and zirconia polishing kit groups showed a statistically very highly significant difference (P<0.001) with (OptraFine® polishing system) and glazing groups. On the other hand, no statistically significant difference was found between glazing and (OptraFine® polishing system) groups (P>0.05). Conclusions: Adjusting full-contour zirconia with diamond bur or disk resulted in a significant increase in (Ra) that necessitates its polishing or glazing to restore the surface smoothness. Furthermore, both glazing and OptraFine® polishing system provided the best surface smoothness, so glazing can be substituted with chairside polishing using OptraFine® polishing system.
This study confirms the ubiquitin conjugating enzyme 2B (Rad6) plays a significant role in the DNA repair pathway also because the ubiquitin-conjugating pathway. The DNA repair pathway could be a variety of bypass repair mechanism where the broken base pair is bypassed by permitting the replication fork to labor under the site of injury. This is often done by a shift mechanism wherever deoxyribonucleic acid enzyme - δ is switched with DNA enzyme - η (DNAP - η). Site of DNAP - η is massive enough to permit the broken ester to labor under, and so bypass the broken nucleotide. However, this is often potential solely through the involvement of Proliferating cell nuclear antigen (PCNA) that could be a processivity issue and it acts as a plat
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In this work, yttrium oxide particles (powder) reinforced AL-Si matrix composites (Y2O3/Al-Si) and Chromium oxide particles reinforced AL-Si matrix composites (Cr2O3/AL-Si) were prepared by direct squeeze casting. The volume percentages of yttrium oxide used are (4, 8.1, 12.1, 16.1 vol %) and the volume percentages of the chromium oxide particles used are (3.1, 6.3, 9.4, 12.5 vol. %). The parameters affecting the preparation of Y2O3/Al-Si and Cr2O3/AL-Si composites by direct squeeze casting process were studied. The molten Al-Si alloy with yttrium oxide particles or with chromium oxide particles was stirred again using an electrical stirrer at speed 500 rpm and the molten alloy was poured into the squeeze die cavity. Th
... Show MoreMetal (III) and (II) coordination compounds of o- phenylenediamine, oxalic acid dihydrate and 8-hydroxyquinoline were synthesized for mixed ligand complexes and characterized using FT-IR, UV-Vis and mass spectra, atomic absorption, elemental analysis, electric conductance and magnetic susceptibility measurements. In addition, thermal behavior (TGA) of the metal complexes (1-6) showed good agreement with the formula suggested from the analytical data. The stoichiometric reaction between the metal (III) and (II) ions with three various ligands in molar ratio at aqueous ethyl alchol for (1:1:1:1) (M: O-PDA: OA: 8-HQ) [where M = Cr+3, Mn+2, Co+2, Ni+2. Cu+2 and Zn+2; O-PDA = O-Phenylenediamine; OA = Oxalic acid and 8-HQ = 8-Hydroxyquinoline]. R
... Show MoreProteus mirabilis ? -lactamase of local isolates number 4TF represent karkh side and 20TF represent rusafa side of Baghdad were extracted and purified 23.17, 25.23 fold with yield of 36.66 %, 37.5% and specific activity 11.8, 12.6 of unit/ mg protein by DEAE –cellulose and Sepharose 4B (respectively ).Molecular weight of both enzyme was about 35500 Dalton determined by gel filtration. The study indicated that the isoelectric point of purified ? -lactamase that extracted from isolate number 4TF and 20TF was 5.4.
In recent years , the interest in gold (III) species have gained more and more attention for cancer chemotherapy , this was stimulating by the possibility to develop new agents with mode of action and clinical profile different from the established platinum metalodrugs.
With this frame, recently new square planar Au(III) complexes (Au(L)(L')n); where L=SCH2COO- ; L'=HSCH2COO- had been synthesized with S/O – donor ligands.
In this article and by the aim to replace, one of (L') ligand by anion chloride ligand (which supposedly more relevant for the biodistribution of the compound than for its pharmacodynamic effects), new complex (Au(L')
The research summarizes the knowledge of the dimensions and denotations of T.V advertisement; and its constituents for building it through the semiotic approach of an ad sample represented by the announcement of Zain Kuwait Telecom Company which carries the title "Mr. President" using Roland Barth's approach, starting with the designation, implicit, and linguistic reading to reach the narrative features and their denotations. That makes television advertising as a semiotic and pragmatic discourse in view of the still and motion picture with its efficiency and strength to inform and communicate. And what lies in it of aesthetic, artistic elements; informational and effective power in influencing the recipients by focusing on narratives and a
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Background: Breast Cancer is the most common malignancy among the Iraqi population; the majority of cases are still diagnosed at advanced stages with poor prospects of cure. Early detection through promoting public awareness is one of the promising tools in its control. Objectives: To evaluate the baseline needs for breast cancer awareness in Iraq through exploring level of knowledge, beliefs and behavior towards the disease and highlighting barriers to screening among a sample of Iraqi women complaining of breast cancer. Methodology: Two-hundred samples were enrolled in this study; gathered from the National
Background: Obesity represents a clear and
present danger to the health of children and
adolescents. Its prevalence among American
youth has doubled in the past 3 decades, and
there are now more overweight and obese
adults in the United States than adults of
normal weight.
Objectives of the study:
1- Finding whether screen watching among
adolescents has an effect on increasing
prevalence overweight and obesity.
2- The effect of other variables like physical
activity, eating in front of screen, eating under
stress on obesity and overweight among the
subjects sample.
Patients &Methods: During 3 months period a
cross sectional survey was conducted on 4
high schools at Baghdad with total
Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorder. To determine the metabolic disorders in women with PCOS, (25) women with PCOS ages (15 - 47) years have been investigated and compared with (20) healthy individuals. All the studied groups were carried out to measure fasting blood sugar, (anti-GAD Ab, anti β-islet cell Ab by IFAT) and measured insulin level by ELISA. There was significant elevation in the concentration of fasting blood sugar than in control groups (p ≤ 0.05) and there was negative results for anti-GAD Ab and anti β-islet cell Ab by IFAT test for serum of women with PCOS, while there was significant differences in the insulin level for women with PCOS compared with control groups (p ≤ 0.05),
... Show MoreBackground: Oral lichen planus (OLP) is a relatively common chronic inflammatory muco-cutaneous disease classified among the potentially malignant lesions of oral mucosa. The aim of this study is to investigate and compare the expression of p53 and PCNA proteins in oral lichen planus and epithelial dysplasia cases. Materials and methods:Formalin-fixed and paraffin- embedded blocks of 21 lichen planusand 21 oral dysplasia cases were referred to immunohistochemical (IHC) analysis for anti p53 and anti PCNA monoclonal antibodies. Results: The results showed that positive nuclear staining for p53 was found in 11/21 (52.4%) cases of lichen planus and 17/21 (80.9%) cases of dysplasia. Positivity for PCNA was observed in 18/21(85.7%) of oral li
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