179 research outputs found

    Study of fish meal substitution with earthworm in diet of rainbow trout (Oncorhynchus mykiss)

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    This experiment was carried out to evaluate the effect of earthworm (Eisenia fetida) in diet for rainbow trout in a complete randomized design with 5 treatments in triplicates using 15 cages in a pound for 8 weeks. Ten fish with average weight 120 g was stocked in each replication. The earthworm (as fed) at the levels of 0, 25, 50, 75 and 100% was replaced with fish meal in rainbow trout diet. Results showed that feed intake decreased significantly (P b0.05). The chemical composition analysis of fish meat showed that there were no significant effects between control and 25% and 50% earthworm in diet for dry matter, crude protein and ash, but fat content significantly decreased as earthworm increased (P < 0.05). This present study showed that the earthworm (Eisenia fetida) can be used in rainbow trout diet up to 50% instead of fish meal

    Optimized Er: YAG Laser Irradiation Distance to Achieve the Strongest Bond Strength Between Orthodontic Brackets and Zirconia-Ceramics

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    Introduction: In recent decades zirconium oxide has been introduced in the field of dentistry as a high-strength ceramic. Unlike its mechanical advantages, however, due to its inert chemical properties, it bonds poorly to other substrates, so improving bonding strength to an adhesive material is necessary.Methods: In this experimental study, 70 ceramic zirconia blocks were prepared and distributed randomly among 7 groups. Then the shear bond strengths were determined and the samples were examined by a scanning electron microscope (SEM). Statistical analysis was performed by one-way ANOVA and multiple Tukey comparisons.Results: One-way analysis of variance (ANOVA) showed that laser irradiation distance has a significant effect on orthodontics brackets bond strength to zirconia-ceramics. Based on the Tukey post hoc test, each group was compared with other groups and the contact mode and 2 mm distance groups showed significantly higher bond strength than other groups (P-value &lt;0.05).Conclusion: Orthodontic bracket bond strength to zirconia-ceramics will be reduced by increasing Er: YAG laser irradiation distance from samples. The highest bond strength will be achieved when the laser irradiation distance is 2 mm or when the laser beam is in contact with samples.

    Facile synthesis of B/g-C3N4 composite materials for the continuous-flow selective photo-production of acetone

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    In this work versatile boron–carbon nitride composite materials were synthesized and utilized in a sustainable process using sunlight as the energy source for the continuous-flow selective photocatalytic production of acetone from 2-propanol. It is worth highlighting that the sample preparation was carried out by an environmentally friendly strategy, without a solvent or additional reagents. Samples containing boron in 1–10 wt% were subjected to physico-chemical characterization using XRD, porosimetry, UVvisible spectroscopy, TEM, energy-dispersive X-ray spectroscopy and XPS. The reaction output was analyzed on the basis of the reaction rate, selectivity and quantum efficiency of the process. A correlation analysis between catalytic properties with two observables, the boron phase distribution in the materials and charge handling efficiency (measured using photoluminescence), rationalizes photoactivity. Such an analysis indicates that the presence of an amorphous boron metallic phase and its contact with the carbon nitride component are key to setting up a renewable and easily scalable chemical process to obtain acetone.MINECO (Spain) ENE2016-77798-C4-1-RConsejo Superior de Investigaciones Cientificas (CSIC)Secretaria de Ciencia Tecnologia e Innovacion of CDMX (SECTEI, Mexico)MINECO CTQ2016-78289-PEuropean Union (EU)RUDN University Program 5-10

    Economic Analysis of Law on Limitation (Lapse of Time)

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    In very simple words, Economic Analysis of Law is an instrumental use of law in order to bring efficiency. In this regard, many aspects of legal thought and institutions may be evaluated according to their role in bringing economic efficiency to the society. In this essay, we will discuss the so-called Prescription as a legal institution. The most important questions which in this essay we are going to answer are: Is the economic analysis of prescription the same as evaluating advantages of prescription –which has a profound literature– or it is another concept? Is prescription an efficient policy to the economists or it is wholly or partly inefficient? By assuming that it is an efficient device, how should be its start, end, suspension, interruption and resume? This essay is divided into two topics of discourse: First, we will explain related key concepts. Then, in the last topic of discourse, the economic analysis of prescription as a matter of law will be rendered

    Connective tissue graft vs. emdogain: A new approach to compare the outcomes

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    Background: The aim of this clinical trial study was to clinically evaluate the use of enamel matrix protein derivative combined with the coronally positioned flap to treat gingival recession compared to the subepithelial connective tissue graft by a new method to obtain denuded root surface area. Materials and Methods: Thirteen patients, each with two or more similar bilateral Miller class I or II gingival recession (40 recessions) were randomly assigned to the test (enamel matrix protein derivative + coronally positioned flap) or control group (subepithelial connective tissue graft). Recession depth, width, probing depth, keratinized gingival, and plaque index were recorded at baseline and at one, three, and six months after treatment. A stent was used to measure the denuded root surface area at each examination session. Results were analyzed using Kolmogorov-Smirnov, Wilcoxon, Friedman, paired-sample t test. Results: The average percentages of root coverage for control and test groups were 63.3% and 55%, respectively. Both groups showed significant keratinized gingival increase ( P 0.05). The results of Friedman test were significant for clinical indices ( P < 0.05), except for probing depth in control group ( P = 0.166). Conclusion: Enamel matrix protein derivative showed the same results as subepithelial connective tissue graft with relatively easy procedure to perform and low patient morbidity

    Comparison of salivary calcium, phosphate and alkaline phosphatase in children with severe, moderate caries and caries free in Tehran's kindergarthens

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    Background: The most common dental disease in childhood is dental caries. This study was carried out to recognize the components of saliva which are protective factors in children in order to evaluate and predict caries susceptible and caries resistant individuals. Methods: A total of 75 subjects of either sex aged 3-5 years old from kindergartens in Tehran were selected and divided into 3 groups (case group: dmft>6, control group 1: 1<6, control group 2: dmft<1). Unstimulated whole saliva was collected and assayed by biochemical methods to determine salivary calcium, inorganic phosphate and alkaline phosphatase. Results: There was no significant changes in salivary calcium, phosphate and alkaline phosphatase activity and their ratio with progress of disease (P>0.05). However, the results showed that salivary phosphate and alkaline phosphatase in caries free group and calcium in the group with severe caries was somewhat more than those in other groups. Conclusions: Despite the results of the present study, the relationship between salivary components and caries rate in children remainslcontroversial. So, more and wide studies are necessary to achieve some practical criteria for predicting dental caries, recognition of susceptible persons and finally prevention of caries in children

    Comparison between preparative methodologies of nanostructured carbon nitride and their use as selective photocatalysts in water suspension

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    Carbon nitride photocatalysts have been prepared by different methodologies, such as chemical ultrasonic irradiation (sonochemical treatment), hydrothermal and ball milling and thermoexfoliation, and have been used for the selective oxidation of 5-hydroxymethyl-2-furaldehyde (HMF) to form 2,5-furandicarboxyaldehyde (FDC) in water suspension both under UV and natural solar irradiation. The physico-chemical features of the photocatalysts have been studied by X-ray diffraction, infrared spectroscopy, UVĂąVis diffuse reflectance spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, and specific surface area measurements. The results indicate that exfoliation of carbon nitrides can increase the conversion of HMF and the selectivity to FDC. In particular, samples exfoliated by both thermal and acidic ultrasonic irradiation treatments showed the best photocatalytic performance
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