Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of the crown, closer to the lateral incisor. The linear displacement of the teeth, strains of the periodontal ligament, and stresses in PEEK wire and composite were evaluated. The data was numerically produced with color coded display by the software. Selected values were tabulated and compared among models. Results: The amount of linear displacement and strain was very low. Stresses in the wire and composite were affected by the size and position of the composite bonding spot. The safe limits were identified at 235 MPa for PEEK and 100 MPa for composite. The basic model had a von Mises stress in the PEEK wire of 122.09 MPa, and a maximum principal stress in the composite of 99.779 MPa. Both stresses were within the safe limits, which means a lower risk of failure in PEEK and composite. All other models had stresses that exceeded the safe limit of the composite. The 3 mm composite model was the only one that developed stresses in the wire more than the safe limits of PEEK. Conclusions: Within the limitations of this study, bonding PEEK wires with 4 mm bonding spots to the clinical crown center provided the best mechanical performance of the wires and spots; otherwise, the mechanical properties of the wire and composite would be affected and, therefore, might affect the retention process. Keywords: Retention, PEEK, Finite element analysis
Parkinson’s disease (PD) consider as a progressive ageing neurodegenerative disease, Parkinson’s consider as a heterogenous disease, with mainly initiate through correlation between genetic and epigenetic by inducing of different factors on some related genes, these factors like (environmental, toxicants, nutrition, heavy metals, pesticides, some drugs) and also(trauma on head ,strokes) in addition to unknown reasons which cause an idiopathic PD .Current study aims to focusing on specific related PD gene called SNCA by single nucleotides polymorphism (rs2619363) as a risk factor for PD initiation disease in PD patients in addition to study the effect of polymorphisms on random Iraqi patients with different gastrointestinal
... Show MorePolycrystalline Cadmium Oxide (CdO) thin films were prepared
using pulsed laser deposition onto glass substrates at room
temperature with different thicknesses of (300, 350 and 400)nm,
these films were irradiated with cesium-137(Cs-137) radiation. The
thickness and irradiation effects on structural and optical properties
were studied. It is observed by XRD results that films are
polycrystalline before and after irradiation, with cubic structure and
show preferential growth along (111) and (200) directions. The
crystallite sizes increases with increasing of thickness, and decreases
with gamma radiation, which are found to be within the range
(23.84-4.52) nm and (41.44-4.974)nm before and after irradiation for
An experiment was carried out to study the effect of soil organic carbon (SOC) and soil texture on the distance of the wetting front, cumulative water infiltration (I), infiltration rate (IR), saturated water conductivity (Ks), and water holding capacity (WHC). Three levels ( 0, 10, 20, and 30 g OC kg-1 ) from organic carbon (OC) were mixed with different soil materials sandy, loam, and clay texture soils. Field capacity (FC) and permanent wilting point (PWP) were estimated. Soil materials were placed in transparent plastic columns(12 cm soil column ), and water infiltration(I) was measured as a function of time, the distance of the wetting front and Ks. Results showed that advance we
Background: Heterocyclic compounds and its derivatives have biological activities and used as analgesic, anti-helminthic, antituberculer, antifungal, antiviral, anticancer and inhibitor of some enzymes. Oxazepine (benzodiazepine) derivative used in relief of psychoneuroses characterized by anxiety and tension. Alkaline phosphatase (ALP) hydrolyzes phosphate monoesters, while Lactate dehydrogenase (LDH) catalyses oxidation of L-lactate to pyruvate utilizing NAD+Objective: The study was carried out to know of the impact of 1,3-oxazepine derivative on the ALP and LDH enzyme activity on human serum in vitro.Methods: The study included the effect of synthesized 1,3-oxazepine divertive [(Z)-3-(5-mercapto-1-3,4-Thiadizol-2-yl)-2-(4-nitroph
... Show MoreThe poor hole cleaning efficiency could causes many problems such as high torque, drag, poor hydraulics and pipe stuck. These inherent problems result in an avoidable high operation cost which this study tried to address. In this study, the effect of cutting density on hole cleaning efficiency in deviated and horizontal wells was investigated. Experiments were conducted using 40 feet (12 m) long of flow loop made from iron and PVC. However, the test section was made from PVC with (5.1m) long and (4” ID) for outer pipe and (2” OD) inner pipe. The cutting transport ratio (CTR) was determined from weight measurements for each test. Cutting Transport Ratio has been investigated for effects of the following parameters; flow rate, cu
... Show MoreIn situ gel can be defined as a polymer solution administered as a liquid and when exposed to some physiologic condition such as thepH, ionic, temperature modulation or solvent and UV induced gelation undergo to phase transition to a semisolid gel. Ketotifenfumarate belongs to the histamine H1 receptor antagonists, and Ketotifen fumarate is used in the treatment of allergic conditions likeconjunctivitis and rhinitis. This work aims to study the natural polymer effects (xanthan gum,gellan gum) on the properties of pH-trigger in situ ocular gel, then compared the drug-releasing rate of optimized formula with the market ketotifen eye drop. Eightformulations (F1-F8) were prepared using different concentrations of xanthan gum, gellan gum with ca
... Show MoreThe photocatalyst process is considered the most promising method for the removal of water contamination. For excellent chemical and structural properties of Co3O4 nanoparticles, various Co3O4-based nanostructures can be applied as a photocatalyst. In this work, carbon quantum dots is prepared via an eco-friendly process and linked to Co3O4 effectively. X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible absorption spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The photocatalyst process reveals that prepared nanocomposites can be degraded methylene blue under solar irradiation strongly. Results showed that methylene blue and methyl orange are degraded via
... Show MoreLead acetate as one of the environmental pollutants can threats the life of living creatures in many ways, it has a long half-life, accumulates mainly in the soft tissue and leads to adverse effects in these tissues. An experiment was conducted to study the effect of oral feeding of lead acetate on histological features of liver, kidney, testis and muscle of albino mice. Mice were treated with 0.05 mg/100 ml lead acetate (LA) for 10 days (group A) and for and for 20 days (group B) and for 30 days (group C). The histological section of liver of mice group A characterized by slightly blurred trabecular structure with foci of hepatitis which increased with cytoplasmic vacules in group B but in group C liver reveal necrosis, heamorrhage,
... Show MoreKlebsiella pneumoniae have an ability to form biofilm as one of strategies to persist and overcome host defenses. The study aims to evaluate the effectiveness of rosemary essential oil alone and in combination with some antibiotics against biofilm of K. pneumoniae isolated from urine. The antibiotics resistance pattern by disc diffusion method and minimal inhibitory concentration (MIC) of gentamicin, ciprofloxacin, amoxicillin, trimethoprim/ sulfame- thoxazole, cefotoxime and rosemary essential oil were determined. The ability to form biofilm as well as inhibition of biofilm formation of K. pneumoniae was performed. MICs 128, 0.25, 768, 64, 384 and 10 µg/ml were used. The effect of MIC and 1/2 MIC of antibiotics and rosemary essential oil
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