2,478 research outputs found

    Fabrication and Mechanical Properties of Chitosan-Montmorillonite Nano-composite

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    Chitosan has found various applications in gastrointestinal stent, biomedical implants as well as an effective absorbent in waste water treatment. However, the material suffers from low strength and large shrinkage upon dehydration. The current project is aimed to develop a process to fabricate chitosan composites with the addition of functionalised montmorillonite nanoparticles and to examine the effect of ceramic content on the mechanical behavior of the composites. This paper describes the fabrication of chitosan with montmorrillonite composites and the mechanical testing of the samples and the mechanical behaviour of the composites, as well as the observations of the microstructure. The effects of composition and microstructure on the mechanical properties of the composite are investigated. The results indicate that the nanoparticles are dispersed uniformly in the matrix up to 40wt% using high speed homogeniser. The elastic modulus increases monotonically with the addition of nanoparticles, but the fracture strength drops due to the defects introduced by the nanoparticles.</jats:p

    A Descriptive Morphology of the Ant Genus Procryptocerus (Hymenoptera: Formicidae)

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    Morphology is the most direct approach biologists have to recognize uniqueness of insect species as compared to close relatives. Ants of the genus Procryptocerus possess important morphologic characters yet have not been explored for use in a taxonomic revision. The genus is characterized by the protrusion of the clypeus forming a broad nasus and antennal scrobes over the eyes. The toruli are located right posterior to the flanks of the nasus opposite to each other. The vertex is deflexed posteriorly in most species. An in-group comparison of the external morphology is presented focusing on the workers. A general morphology for gynes and males is also presented. Previously mentioned characters as well as new ones are presented, and their character states in different species are clarified. For the metasoma a new system of ant metasomal somite nomenclature is presented that is applicable to Aculeata in general. Finally, a Glossary of morphological terms is offered for the genus (available online). Most of the terminology can be used in other members of the Formicidae and Aculeata

    RPA using a multiplexed cartridge for low cost point of care diagnostics in the field

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    A point of care device utilising Lab-on-a-Chip technologies that is applicable for biological pathogens was designed, fabricated and tested showing sample in to answer out capabilities. The purpose of the design was to develop a cartridge with the capability to perform nucleic acid extraction and purification from a sample using a chitosan membrane at an acidic pH. Waste was stored within the cartridge with the use of sodium polyacrylate to solidify or gelate the sample in a single chamber. Nucleic acid elution was conducted using the RPA amplification reagents (alkaline pH). Passive valves were used to regulate the fluid flow and a multiplexer was designed to distribute the fluid into six microchambers for amplification reactions. Cartridges were produced using soft lithography of silicone from 3D printed moulds, bonded to glass substrates. The isothermal technique, RPA is employed for amplification. This paper shows the results from two separate experiments: the first using the RPA control nucleic acid, the second showing successful amplification from Chlamydia Trachomatis. Endpoint analysis conducted for the RPA analysis was gel electrophoresis that showed 143 base pair DNA was amplified successfully for positive samples whilst negative samples did not show amplification. End point analysis for Chlamydia Trachomatis samples was fluorescence detection that showed successful detection of 1 copy/ÎŒL and 10 copies/ÎŒL spiked in a MES buffer.Medical Research Counci

    New Symmetries in Crystals and Handed Structures

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    For over a century, the structure of materials has been described by a combination of rotations, rotation-inversions and translational symmetries. By recognizing the reversal of static structural rotations between clockwise and counterclockwise directions as a distinct symmetry operation, here we show that there are many more structural symmetries than are currently recognized in right- or left-handed handed helices, spirals, and in antidistorted structures composed equally of rotations of both handedness. For example, though a helix or spiral cannot possess conventional mirror or inversion symmetries, they can possess them in combination with the rotation reversal symmetry. Similarly, we show that many antidistorted perovskites possess twice the number of symmetry elements as conventionally identified. These new symmetries predict new forms for "roto" properties that relate to static rotations, such as rotoelectricity, piezorotation, and rotomagnetism. They also enable symmetry-based search for new phenomena, such as multiferroicity involving a coupling of spins, electric polarization and static rotations. This work is relevant to structure-property relationships in all material structures with static rotations such as minerals, polymers, proteins, and engineered structures.Comment: 15 Pages, 4 figures, 3 Tables; Fig. 2b has error

    A cross validation of Consumer-Based Brand Equity (CBBE) with Private Labels in Spain

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    Molinillo,S., Ekinci, Y., Japutra, A. (2014)'A cross validation of Consumer-Based Brand Equity (CBBE) with Private Labels in Spain'. in Martínez-López, Gázquez-Abad, J.C. and Sethuraman, R. J.A. (eds.) Advances in National Brand and Private Label Marketing. Second International Conference, 2015. Springer Proceedings in Business and Economics, pp. 113-125In recent years a number of Consumer-Based Brand Equity (CBBE) models and measurement scales have been introduced in the branding literature. However, examinations of brand equity in Private Labels (PL) are rather limited. This study aims to compare the validity of the two prominent CBBE models those introduced by Yoo and Donthu (2001) and Nam et al. (2011). In order to test the models and make this comparison, the study collected data from 236 respondents who rated private labels in Spain. A list of 30 different fashion and sportswear PL was introduced to respondents. These brands do not make any reference to the retail store in which they are sold. Research findings suggest that the extended CBBE model introduced by Nam et al. (2011) and Ciftci et al. (2014) is more reliable and valid than Yoo and Donthu’s model for assessing PL. Theoretical contributions and managerial implications are discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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