The 10 most-cited articles in Heliyon, 2017

The present study explored the relationship between risky cybersecurity behaviours, attitudes towards cybersecurity in a business environment, Internet addiction, and impulsivity. 538 participants in part-time or full-time employment in the UK completed an online questionnaire, with responses from 515 being used in the data analysis. The survey included an attitude towards cybercrime and cybersecurity in business scale, a measure of impulsivity, Internet addiction and a 'risky' cybersecurity behaviours scale. The results demonstrated that Internet addiction was a significant predictor for risky cybersecurity behaviours. A positive attitude towards cybersecurity in business was negatively related to risky cybersecurity behaviours. Finally, the measure of impulsivity revealed that both attentional and motor impulsivity were both significant positive predictors of risky cybersecurity behaviours, with non-planning being a significant negative predictor. The results present a further step in understanding the individual differences that may govern good cybersecurity practices,…

Poloxamers are triblock copolymers with a center block of hydrophobic polypropylene oxide (PPO) flanked by two hydrophilic polyethyleneoxide (PEO) blocks. Among this family of copolymers, poloxamer 407 is a non-ionic surfactant with reversible gelation properties above a particular polymer concentration and a particular temperature. Easy preparation of poloxamer 407 based sterile injectable formulations have made this copolymer a good candidate for drug delivery, specifically when controlled release of the drug is required. Previously, the applications of compendial poloxamer 407 preparations were demonstrated; however, low viscosity, poor elasticity, and sol-to-gel transition temperature (T sol-gel ) over a wide temperature range were observed. A purification process was introduced to eliminate impurities and low molecular weight copolymer molecules from the compendial poloxamer 407 resulting in higher viscosity values with T sol-gel in a narrow temperature range. Here, poloxamer 407 was purified based on the proposed process and the rheological and analytical evaluation of the…

Micro-ring structured zinc oxide (ZnO) thin films were prepared on glass substrates by spray pyrolysis and their structural, morphological, optical and electrical properties were investigated. X-ray Diffraction (XRD) analysis revealed the films' hexagonal wurtzite phase with a preferred (002) grain orientation. The mean crystallite size calculated on the basis of the Debye-Scherrer model was 24 nm and a small dislocation density of [Formula: see text] was obtained, indicating the existence of few lattice defects and good crystallinity. Scanning Electron Microscopy (SEM) micrographs revealed the film's granular nature composed of rod-shaped and spherical nanoparticles which agglomerated to form micro-ring like film clusters on the film surface. The average transmittance in the visible region, optical band gap and Urbach energy were approximately 75-80%, 3.28 eV and 57 meV, respectively. The refractive index and extinction coefficient were determined using Swanepoel's envelope method. Raman spectroscopy revealed the presence of small amounts of residual tensile stress and low density…

The late persistence in Southern Iberia of a Neandertal-associated Middle Paleolithic is supported by the archeological stratigraphy and the radiocarbon and luminescence dating of three newly excavated localities in the Mula basin of Murcia (Spain). At Cueva Antón, Mousterian layer I-k can be no more than 37,100 years-old. At La Boja, the basal Aurignacian can be no less than 36,500 years-old. The regional Middle-to-Upper Paleolithic transition process is thereby bounded to the first half of the 37th millennium Before Present, in agreement with evidence from Andalusia, Gibraltar and Portugal. This chronology represents a lag of minimally 3000 years with the rest of Europe, where that transition and the associated process of Neandertal/modern human admixture took place between 40,000 and 42,000 years ago. The lag implies the presence of an effective barrier to migration and diffusion across the Ebro river depression, which, based on available paleoenvironmental indicators, would at that time have represented a major biogeographical divide. In addition, (a) the Phlegraean Fields…

The health of children in Ghana has improved in recent years. However, the current prevalence rates of malnutrition remain above internationally acceptable levels. This study, therefore, revisits the determinants of child health by using Ghana's Multiple Indicator Cluster Survey to investigate the effect of infant feeding practices on child health. We used the World Health Organization's Infant and Young Children Feeding guidelines to measure dietary quality. The econometric analyses show that dietary diversity may cause improvement in children's health in Ghana. This suggests that educational campaigns on proper infant feeding and complementary dieting could be an effective means of improving the health of children in Ghana.

Nickel and cobalt sulfides are promising materials in different cutting-edge research areas like solar cells, supercapacitors, catalysts, and electrode materials. Nickel and cobalt sulfides with various stoichiometries have been synthesized sonochemically from Ni(CH 3 COO) 2 ∙ 4H 2 O, Co(CH 3 COO) 2 ∙ 2H 2 O and different sulfur precursors using a direct immersion ultrasonic probe. The products were characterized by X-ray powder diffraction, transmission electron microscopy (TEM) including EDX analysis, IR and UV–Vis spectroscopy and elemental analysis. Following products have been obtained: NiS, Ni 3 S 4 , CoS 1.097 and Co 9 S 8 , with average crystallite sizes in the range 7−30 nm. Effects of different reaction conditions on the size, morphology and optical band-gap energy were evaluated. Optical band-gap energies in the range 3.3 eV−3.8 eV were observed for the obtained nanoparticles.

Waste sardine oil, a byproduct of fish industry, was employed as a low cost feedstock for biodiesel production. It has relatively high free fatty acid (FFA) content (32 mg KOH/g of oil). Lipase enzyme immobilized on activated carbon was used as the catalyst for the transesterification reaction. Process variables viz. reaction temperature, water content and oil to methanol molar ratio were optimized. Optimum methanol to oil molar ratio, water content and temperature were found to be 9:1, 10 v/v% and 30 °C respectively. Reusability of immobilized lipase was studied and it was found after 5 cycles of reuse there was about 13% drop in FAME yield. Engine performance of the produced biodiesel was studied in a Variable Compression Engine and the results confirm that waste sardine oil is a potential alternate and low-cost feedstock for biodiesel production.

Titanium dioxide (TiO 2 ) nanoparticles were prepared by the sol-gel method at different pH values (3.2–6.8) with a hydrochloric acid (HCl) solution. Raw samples were calcined at 500 °C for 2 h. The effects of pH on the structural, morphological and optical properties of TiO 2 nanoparticles were investigated. At pH 4.4–6.8, only the anatase phase of TiO 2 was observed. Under strong acidic condition at pH 3.2 rutile, brookite and anatase co-exist, but rutile is the predominant phase. The strain value increased and the crystallite size decreased as the HCl content increased. The increased crystallite sizes in the range 21–24 nm and enhanced blue emission intensity around 432 nm was obtained for the sample at pH 5.0. Experimental results showed that TiO 2 nanoparticles synthesized at pH 5.0 exhibited the best luminescence property with pure anatase phase.

Effect of hydrothermal treatment, acid washing and annealing temperature on the structure and morphology of TiO 2 nanotubes during the formation process was assessed. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy analysis were conducted to describe the formation and characterization of the structure and morphology of nanotubes. Hydrothermal treatment of TiO 2 precursor nanoparticles and acid washing are fundamental to form and define the nanotubes structure. Hydrothermal treatment causes a change in the crystallinity of the precursor nanoparticles from anatase phase to a monoclinic phase, which characterizes the TiO 2 nanosheets structure. The acid washing promotes the formation of high purity nanotubes due to Na + is exchanged from the titanate structure to the hydrochloric acid (HCl) solution. The annealing temperature affects the dimensions, structure and the morphology of the nanotubes. Annealing temperatures in the range of 400 °C and 600 °C are optimum to maintain a highly stable tubular…

Energy harvesting is a promising technology that powers the electronic devices via scavenging the ambient energy. Piezoelectric energy harvesters have attracted considerable interest for their high conversion efficiency and easy fabrication in minimized sensors and transducers. To improve the output capability of energy harvesters, properties of piezoelectric materials is an influential factor, but the potential of the material is less likely to be fully exploited without an optimized configuration. In this paper, an optimization strategy for PVDF-based cantilever-type energy harvesters is proposed to achieve the highest output power density with the given frequency and acceleration of the vibration source. It is shown that the maximum power output density only depends on the maximum allowable stress of the beam and the working frequency of the device, and these two factors can be obtained by adjusting the geometry of piezoelectric layers. The strategy is validated by coupled finite-element-circuit simulation and a practical device. The fabricated device within a volume of 13.1 mm 3…