Background: Sliding mechanics is widely used during orthodontic treatment. One of the disadvantages of this mechanics is the friction generated at the bracket/archwire interface, which may reduce the amount of desired orthodontic movement obtained. The aim of the present in vitro study was to evaluate and compare the static frictional forces produced by two passive self-ligating brackets stainless-steel and hybrid and two conventional brackets stainless-steel and monocrystal ligated with stainless-steel ligature wire at two degrees of torque(zero and twenty) under dry condition. Materials and method: One hundred and sixty brackets were used in this study divided into four groups each group consisted of forty brackets these are: Two self-ligating (stainless-steel and Hybrid) while the two conventional types are the (stainless-steel and monocrystal).twenty of each group examined with 0.016"x0.022"archwire, ten at 0? torque and ten at 20? torque while the other twenty of each group examined with 0.019"x0.025", ten at 0? torque and ten at 20? torque. Results: There was a significant different between all groups except in case when self-ligating brackets (both types) ligated to both wires at 0?torque there was no significant difference. Conclusions: The self- ligating brackets produce significantly lower static friction than the conventional types at both degrees of torque. There was no significant different between both self-ligating brackets at0?torque while at 20? torque the stainless- steel self –ligating produce lower static friction than the clear self-ligating type.
Fine aggregates used for concrete works in Sulaymaniyah city frequently fail to meet the standard requirements for gradation and fineness modulus in cement concrete. This paper aims to critically evaluate gradation, fineness modulus, and clay contents of various natural sands produced and used for concrete work in the region. Sixteen field sand samples were collected from various sites in Darbandikhan (5 samples), Qalat Dizah (5 samples), Koysinjaq (5 samples), and Piramagroon (1 sample) confirming to ASTM D75. The field samples were parted into test specimens based on ASTM C702. Then, sieve analysis was carried out on the oven-dry test specimens in compliance with ASTM C136. The test results of fine aggregates wer
... Show MoreIn this research work, a simulator with time-domain visualizers and configurable parameters using a continuous time simulation approach with Matlab R2019a is presented for modeling and investigating the performance of optical fiber and free-space quantum channels as a part of a generic quantum key distribution system simulator. The modeled optical fiber quantum channel is characterized with a maximum allowable distance of 150 km with 0.2 dB/km at =1550nm. While, at =900nm and =830nm the attenuation values are 2 dB/km and 3 dB/km respectively. The modeled free space quantum channel is characterized at 0.1 dB/km at =860 nm with maximum allowable distance of 150 km also. The simulator was investigated in terms of the execution of the BB84 prot
... Show MorePolymeric microsphere devices occupy a wide range in the field of controlled drug delivery. Subcutaneous injectable preparations of Poly(Lactide-co-Glycolide) (PLGA) microsphere of Daptomycine were prepared by solvent extraction/evaporation technique using different copolymers ratio and molecular weights. Four formulations were prepared (F1-F4) and characterized in term of particle size, surface morphology, bulk density and porosity in addition to the drug content. The effects of the above parameters on the in-vitro release study were evaluated. These formulas were evaluated also for their in-vivo release profile using rat (as an animal model) and
... Show MoreAs a well-known oral and intravenous antifungal, voriconazole (VRN) has an extensive history of usage in the medical field. Solid lipid nanoparticles (SLNs) have been produced to treat ocular fungal keratitis in the eye. A 32Box-behnken design was used to produce a variety of new formulas for hot-melt extrusion. The SLNs were evaluated by entrapment efficiency (EE percent), particle size (PS), polydispersity index (PDI), and zeta potential (ZP). A series of in-vitro and in-vivo studies were carried out on the new formula. The produced vesicles’ EE, PS, PDI, and ZP values were all good. SLNs eye drops were numerically adjusted to include carbopol, a stabilizer, lipids, and a surfactant, among other substances. ZP of -36.5 ± 0.20 m
... Show MoreOlanzapine (OLZ) is classified as a typical antipsychotic drug utilized for the treatment of schizophrenia. Its oral bioavailability is 60% due to its low solubility and pre-systemic metabolism. Hence, the present work aims to formulate and evaluate OLZ nanoparticles dissolving microneedles (MNs) for transdermal delivery to overcome the problems associated with drug administration orally. OLZ nanoparticles were prepared by the nanoprecipitation method. The optimized OLZ nanoparticle formula was utilized for the fabrication of dissolving MNs by loading OLZ nanodispersion into polydimethylsiloxane (PDMS) micromould cavities, followed by casting the polymeric solution of polyvinylpyrrolidone(PVP-K30) and polyvinyl alcohol (PVA) to form
... Show MoreA new series of 5-methoxy-2-mercapto benzimidazole derivatives were synthesized by the reaction of 5-methoxy- 2-mercaptobenzimidazole with chloroacetic acid and affords 2-((5-methoxy-1H-benzo[d]imidazol-2-yl)thio) acetic acid (1),which on cyclization with acetic anhydride and pyridine gives 7- methoxybenzo[4,5]imidazo[2,1-b]thiazol- 3(2H)-one(2), which on condensation with different aryl aldehydes in the presence of anhydrous sodium acetate in glacial acetic acid, furnishes a arylidene thiazolidinone. The purity of the synthesized compounds was confirmed by melting point and TLC.The structures were established by different spectral analysis such as FTIR,1HNMR, and CHN analysis. The newly synthesized compounds (3a-d) were in vivo evaluated f
... Show MoreBaghdad city has been faced numerous issues related to freshwater environment deteriorations due to many reasons, mainly was the discharge of wastewater without adequate treatment. Al- Rustamiya Wastewater Treatment Plant (WWTP) have been constructed among many plants in Baghdad city to reduce the amount of wastewater discharged into natural environment and its subsequent adverse effects. This study was conducted to evaluate the performance of the plant which consist of a conventional activated sludge (CAS) and sequencing batch reactors (SBR) systems as secondary treatment units and its ability to meet Iraqi specifications. A reliability level determination and analysis also were conducted to find the plant's stability and its capabi
... Show MoreBackground: low back pain is one of the most common public health problems and of the most common musculoskeletal complaint. Many risk factors have been considered for developing low back pain include smoking, obesity and sedentary lifestyle.
Aim of study: To evaluate smoking, obesity, and sedentary lifestyle associations with low back pain in young adults aged (18 – 39 years).
Methods: a comparative cross sectional study for young adults aged 18 – 39 years, participants with low back pain as a symptom constitutes the first group, others free of this symptom considered as the control group. Age and gender matched in both groups. Smoking, obesity and sedentary life sty
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