133 research outputs found

    Molar tubes and failure rates–A review

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    Objectives: To review the failure rates of molar tubes and the effect of molar tube base design, adhesive type, and bonding technique on the failure rates of molar tubes. Data: The revolution of molar bonding greatly impacted fixed orthodontic appliance treatment by reducing chair-side time and improving patient comfort. Even with the many advantages of molar bonding, clinicians sometimes hesitate to use molar tubes due to their failure rates. Sources: Internet sources, such as Pubmed and Google Scholar. Study selection: studies testing the bond failure rate of molar tubes. Conclusions: The failure rate of the molar tubes can be reduced and the bond strength of the molar tubes can be improved by changing the design of the molar tube base, the adhesive type, and the bonding techniqu

    Contemporary orthodontic archwires: A literature review

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    Archwires are the principal force generators used in orthodontic treatment. They are one of the fixed appliances’ active components. They produce various tooth movements by interaction with brackets and buccal tubes. Recent advancements in orthodontics have resulted in a wide variety of archwire alloys with a broad spectrum of characteristics. The proper application of these wires can shorten treatment duration, improve patient comfort, and reduce chairside time. Furthermore, the need for esthetic orthodontic treatment alternatives resulted in the introduction of esthetic archwires. These innovative archwires attempt to combine both the esthetics and good clinical performance.  Understanding recen

    Prediction and analysis of fabric-evoked prickle properties of different textile woven fabrics using Artificial Neural Networks method

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    This paper aims to discuss the design and development of an Artificial Neural Networks (ANNs) model to understand a human perception of the tactile prickliness properties of textile wear fabric materials, and create an objective system to express those prickle perceptions in terms of measurable mechanical properties. The objective and also subjective hand measurement of the textile materials used for wear fabric has been check up on with consideration given the aspects of both dermatitis and comfort. In this study, attempt to predict the prickliness (itchiness) of wear fabric by their physical properties using a back-propagation network and a stepwise regression. Handle properties of fabrics were measured by universal test equipment (KES-F) and total prickle-score (TPS) values of the wear fabrics were determined by a group of panelists consisting of some textile experts. The optimum construction of neural network was investigated through the change of layer and neuron number. The results showed that the back-propagation network could predict the (TPS) values of wear fabric with a meaningful difference. These wear fabrics were used to show that the results of neural network were in good agreement with subjective test results

    Study of the Rheological Behavior of Polyamide 5,6 (PA5,6

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    The rheological behavior of polymer melts and polymer solutions are of great importance in polymer processing, particularly for the analysis and design of processing operations as well as understanding the relationship between structures and properties of the final-products. The objective of the present work was to investigate the rheological behavior of polyamide 5,6  (PA5,6) to obtain information on the effect of temperature on the melt behavior of polyamide 5,6 compared to that of polyamide 6. The rheological properties of polyamide 5,6 (PA5,6) have been studied by means of a Haake  rheometer. The effect of temperature on the storage modulus, loss modulus, and complex viscosity was studied. The obtained results showed that the complex viscosity, storage modulus, and loss modulus of PA5,6 and PA6 decrease with increase of the temperature. It is worth noting that the complex viscosity of PA5,6 remains almost constant showing a Newtonian behavior, on the other hand, the complex viscosity of PA6 slightly decreases with the increase of shear rate exhibits a much nearly Newtonian behavior. Similar behavior was observed for other polyamides such as polyamide 6.6 and polyamide 6.,1

    Comparison of conjugated linoleic acid and other fatty acid content of milk fat of mafriwal and jersey cows.

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    Special attention has been given to the milk Fatty Acids (FA) that have a beneficial effect for human health such as mono and poly unsaturated fatty acids in particularly the Conjugated Linoleic Acids (CLA). This study was undertaken to investigate the milk fat contents of CLA variables (CLA and CLA-desaturase index) and other FA composition of Mafriwal and Jersey cows under same feeding system. In addition, the relationship between these two CLA variables with milk production and milk fat percent was determined. All the cows were grazed on pasture and given 5.5 kg of concentrate per head daily. Milk FA composition was determined using gas chromatography after extraction of milk fat using modified Folch's method. The results showed a significant variation (p<0.05) in the FA contents of the two breeds. The cis-9, trans-II CLA and CLA-desaturase index in milk fat of Mafriwal were significantly higher (p<0.05) than that of Jersey cows. Mafriwal cows produced significantly (p<0.05) higher concentrations of C18:0, C18:1cis-9, C18:3 and C20:1 than that of Jersey, while Jersey cows produced significantly (p<0.05) higher concentrations of C12:0 and C14:0 than Mafriwal cows. Additionally, significant positive correlations were observed between CLA variables and milk production. This study indicates that the breed of cows has an effect on CLA and other FA composition of milk fat and Mafriwal cows produced significantly higher percentages of CLA than Jersey cows which would provide better benefits for human health. Furthermore, the milk fat content of CLA and CLA-desaturase index were positively related to the milk production

    Detection of Trypanozoon trypanosomes infections on Glossina fuscipes fuscipes (Diptera: Glossinidae) using polymerase chain reaction (PCR) technique in the Blue Nile State, Sudan

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    Tsetse flies transmit many species of trypanosomes in Africa, some of which are human and livestock pathogens of major medical and socio-economic impact. Identification of trypanosomes is essential to assess the disease risk imposed by particular tsetse populations. The present study was carried out to determine the trypanosomal infection rate of tsetse flies (Glossina fuscipes fuscipes) in the Blue Nile State of Sudan. A polymerase chain reaction (PCR) assay was used because of the inherent difficulty of speciating trypanosomal parasites in the fly. Our results show that 4.44% (8/180) of the flies were positive for a Trypanosoma brucei group. Three of eight positive flies reacted with primers for Trypanosoma b. rhodesiense. We did not detect flies infected with T. b. gambiense. Thus, the burden of flies harboring T. b. rhodesiense and T. b. brucei trypanosomes were 1.67 and 2.78%, respectively. This is the first evidence of T. b. rhodesiense in the Yabus District. Thus, HAT case-detection active surveillance and tsetse fly control campaigns should be conducted before the establishment of human settlement, investment of natural resources into agricultural and animal husbandry.Key words: Glossina fuscipes fuscipes, Trypanosoma brucei, T. b. gambiense, T. b. rhodesiense, infection rate, PCR technique, Blue Nile State

    Structural changes in FeOx/γ-Al2O3 catalysts during ethylbenzene dehydrogenation

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    The structural changes that occur in a FeOx/γ-Al2O3 catalyst during the dehydrogenation of ethylbenzene in a fluidized CREC Riser Simulator have been investigated. Chemical and morphological changes are observed to take place as a result of reaction. Electron microscopy reveals the formation of needle-like alumina structures apparently enclosing iron oxide particles. The formation of such structures at relatively low temperatures is unexpected and has not previously been reported. Additionally, X-ray diffraction and Mössbauer spectroscopy confirmed the reduction of the oxidation state of iron, from Fe2O3 (haematite) to Fe3O4 (magnetite). Iron carbides, Fe3C and ɛ-Fe2C, were detected by electron microscopy through electron diffraction and lattice fringes analysis. Carbon deposition (coking) on the catalyst surface also occurs. The observed structural changes are likely to be closely correlated with the catalytic properties of the materials, in particular with catalyst deactivation, and thereby provide important avenues for future study of this industrially important reaction. Fe2O3/Al2O3 catalyst undergoes chemical and morphological changes during ethylbenzene dehydrogenation forming Al2O3 needles which appear to contain reduced Fe3O4 particles. Fe3C also forms during reaction

    Use of Treponema pallidum PCR in Testing of Ulcers for Diagnosis of Primary Syphilis(1.).

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    Treponema pallidum PCR (Tp-PCR) has been noted as a valid method for diagnosing syphilis. We compared Tp-PCR to a combination of darkfield microscopy (DFM), the reference method, and serologic testing in a cohort of 273 patients from France and Switzerland and found the diagnostic accuracy of Tp-PCR was higher than that for DFM
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