Antioxidant and antimicrobial activity evaluation and essential oil analysis of Semenovia tragioides Boiss. from Iran

This study reports the essential oil composition, antioxidant and antimicrobial activity of the essential oil and methanol extract of aerial parts of Semenovia tragioides. GC and GC/MS analysis identified 17 compounds representing 99.4% of the oil. The main components comprising 61.9% of the oil were lavandulyl acetate (25.5%), geranyl acetate (12.5%), trans-β-ocimene (8.8%), p-cymene (7.7%) and γ-terpinene (7.4%). The samples were screened for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and β-carotene/linoleic acid assay methods. None of the plant samples showed appreciable antioxidant activity in DPPH test. However, methanol extract exhibited considerable linoleic acid oxidation inhibition (77.4%) in the β-carotene/linoleic acid test, a value near to that of butylated hydroxytoluene (BHT, 95.6%). Total phenolic content of the plant extract as gallic acid equivalents was 7.5 μg/mg. The essential oil exhibited strong antimicrobial activity against all but one of the tested microorganisms while the plant extract only inhibited two of them weakly.     

The frequency and predictors of helmet use among Iranian motorcyclists: A quantitative and qualitative study

Objective

This study examines the rate of helmet use and identifies barriers and facilitators of wearing helmets among Iranian motorcyclists. A mixed-method approach was used, including a structured seasonal survey with specific observations of a random sample of 6010 riders and qualitative methods that included 29 in-depth interviews and seven focus groups (n = 31).

Results

Only 10% of motorcyclists wear a standard helmet while riding. However, another 23% of motorcyclists used non-standard or partial helmets that covered only part of the head and do not prevent head trauma injuries effectively. We observed only 2 of 264 child passengers and 22 of 1951 adult passengers wearing helmets. Almost no one used protective pants or clothing made to be more visible in traffic. Themes emerged from qualitative interviews and were grouped into three main categories: (1) helmet characteristics; (2) social and cultural factors; and (3) personal and psychological factors.

Conclusion

Overall, the motorcyclists in our study believed that wearing a safety helmet protects them against serious injuries or death during a crash; however, only a small percentage of the motorcyclists used safety helmets. National intervention programs addressing motorcycle safety should aim to overcome barriers to and promote facilitators of helmet use, including providing inexpensive standard helmets, banning manufacturing/using unsafe partial or dummy helmets, as well as enforcing helmet use on a consistent basis.     

Project Delivery System Selection under Uncertainty: Multicriteria Multilevel Decision Aid Model

Selecting an optimal project delivery system is a critical task that owners should do to ensure project success. This selection is a complex decision-making process. The complexity arises from the uncertain or not well-defined parameters and/or the multiple criteria structure of such decisions. In this study, a decision aid model using the analytical hierarchy process (AHP) coupled with rough approximation concepts is developed to assist the owners. The selection criteria are determined by studying a number of benchmarks. The model ranks the alternative delivery systems by considering both benchmark results and owner’s opinion. In interval AHP, an optimization procedure is performed via obtaining the upper and the lower linear programming models to determine the interval priorities for alternative project delivery systems. In cases having incomparable alternatives, which is the most likely case in uncertain decision making, the model uses rough set-based measures to reduce the number of decision criteria to a subset, which is able to fully rank the alternatives. To illustrate the applicability and usefulness of this methodology, a real world case study will be demonstrated.     

Elastic interactive buckling strength of corrugated steel shear wall under pure shear force

Different ways have been presented to prevent elastic buckling of steel shear walls. One of these solutions is corrugated shear wall. In this type of wall, shear buckling strength increases without increasing the thickness of the panel. Numerical modeling results indicate that, always, shear buckling strength of corrugated panels is more than the flat panels and with the right choice of the geometric parameters of corrugated panels; without increasing the thickness of the panel, we can improve buckling strength significantly. In the trapezoidal corrugated panels, reducing the width of the subpanels do not always increase buckling strength of the panel, but it changes the panel buckling shape from the local buckling mode to the global buckling. In addition, in panels, with the low width of the subpanels, elastic buckling does not happen in the subpanels. Comparing numerical analysis with the theoretical relations showed that the results of numerical analysis with the relations that include local buckling, global buckling, and shear yielding stress, have a better approximation and in another word, interaction buckling is the combination of the local buckling, global buckling, and shear yielding stress.     

The Meaning of Home among Elderly Immigrants: Directions for Future Research and Theoretical Development

The paper discusses the notion that, in research on elderly immigrant housing, it is not enough to delineate the residential geography of different elderly immigrant groups or to study the economic and social reasons for their segregated habitations and exclusiveness. It is also necessary to understand, in the spatial context, the degree of integration and the differences between groups. In explaining these differences, consideration should be given to each elderly immigrant group's own value system, norms and preferences. It is argued that one necessary task in this endeavour is to gain knowledge about different elderly immigrant groups' understandings of what a home symbolises - what home means to them in the context of their particular ways of thinking and culture. From this point of view, the paper concludes that, when investigating the meaning of 'home' among elderly immigrants, an integrative theoretical approach based on an experiential perspective and a phenomenological and developmental perspective are deemed appropriate to be adopted.     

A reversible ALU using HNG and Ferdkin gates in QCA nanotechnology

Quantum dot cellular automata (QCA) with the characteristics such as low energy dissipation and high density is a suitable alternative technology to CMOS technology. Arithmetic logic unit (ALU) is one of the most important critical components of a microprocessor, and it is the core component of central processing unit (CPU). In this work, a novel reversible ALU in QCA nanotechnology is proposed. The reversible ALU contains three Ferdkin gates and one HNG gate. The proposed structure needs one constant input and generates only one garbage output. The proposed circuit does not need any rotated cells and only uses one layer that improves the manufacturability of the design interestingly. This circuit can perform 20 operations such as AND, OR, XOR, XNOR, COPY, addition, and increment. Our design contains only 480 cells and 12 majority voters and requires 15 clock phases. The proposed structures are simulated using QCADesigner version 2.0.3. The reversible ALU, despite a 25% increase in operations, has a 28% improvement in cell numbers and a 6% improvement in delay.     

Production of polyvinylpyrrolidone/chiral diacid modified nanocrystalline Mg‐substituted fluorapatite nanocomposites: Morphological and thermal characterization

The main objective of this work was the production of novel polyvinylpyrrolidone/diacid modified Mg‐substituted fluorapatite (DM‐MFA) nanocomposites (NC)s, by sonication process. Mg‐substituted fluorapatite (MFA) powders with a chemical composition of Ca_9.5Mg_0.5(PO₄)₆F₂ were prepared by mechanical alloying technique. Initially, surface of MFA was modified by bioactive chiral diacid monomer, N‐trimellitylimido‐l ‐leucine as a coupling agent to form DM‐MFA nanoparticles. DM‐MFA NPs were utilized as a filler, to give the NCs with potential bioactivity. Examination of transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE‐SEM) microphotographs displayed that, there is no aggregation of a large quantity of particles. The above NCs showed rather improved thermal stability compared with pure polymer. The improvement of thermal behavior was related to the uniform and good dispersion of DM‐MFA in the polymer matrix as well as the strong hydrogen bonding between C?O of PVP and OH of DM‐MFA. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44254.     

Catalytic Oxidation of CO over Nanocrystalline La1–xCexNiO3 Perovskite‐Type Oxides

Nanocrystalline La_1–xCe_xNiO₃ (x = 0.1, 0.3, 0.5, 0.7, 0.9) perovskite‐type oxide catalysts prepared by the Pechini method were employed in catalytic CO oxidation and the effect of substitution of La by Ce on CO conversion was evaluated. The results indicated the remarkable effect of La substitution with Ce on the catalytic performance at low temperatures. The reaction temperature had a significant influence on the stability of the catalysts. The La_0.1Ce_0.9NiO₃ sample exhibited the highest activity among the prepared catalysts in CO oxidation reaction. In addition, the influence of different parameters including pretreatment condition, feed ratio, and gas hourly space velocity (GHSV) on the catalytic performance was examined. The optimum catalyst proved high stability under severe reaction conditions in the presence of water vapor and CO₂ in the feed stream.     

Effect of electrostatic functional monomers on lysozyme recognition by molecularly imprinted hydrogel

Electrostatic functional monomers (EFMs) play an important role in noncovalent molecular imprinting due to their formed complexes with the complementary segment(s) of the template molecule. In this work using UV difference spectroscopy, interaction saturations of methacrylic‐acid and 2‐dimethyl‐amino‐ethyl‐methacrylate in complex formation with lysozyme (Lyz) surface was found to occur at molar ratios to Lyz of 400 and 100, respectively. Based on these results and the estimated free to total EFMs ratios, four sets of imprinted/nonimprinted hydrogel samples were synthesized alongside the two sets based on lysozyme surface charges and equal EFMs. Comparisons showed that the highest absorption capacity of 59 mg/g and imprinting effect of 1.58 correspond to samples with EFM/Lyz ratios at saturation and minimum free to total EFM/Lyz ratios, respectively. Minimization of free monomers is hence important in recognition of proteins by avoiding the nonspecific binding. This can have generic application for specific separation of other macromolecules. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41366.