Electrospun polyurethane and soy protein nanofibres for wound dressing applications

In this report, a novel wound dressing material has been woven by electrospinning technique and tested for its various properties. For the nanofibre mat, a mixture of polyurethane (PU) and soy protein isolate (SPI) was electrospun in conjugation with zinc oxide nanoparticles (ZnO Nps) and ciprofloxacin hydrochloride (CipHCl) to produce fibrous mats viz. PU/SPI/ZnO and PU/SPI/CipHCl. An optimum ratio (1 : 1) of PU/SPI was used as suitable polymeric ratio in order to produce homogenous nanofibres without beads having an average diameter in the range of 300–350 nm. The electrospun nanofibre‐based mats were characterised using X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis and scanning electron microscope. The mechanical properties of the nanofibrous mats were tested using universal testing machine. The wettability analysis was done using the contact angle measurement based on the sessile drop test. This study revealed that the electrospun PU/SPI‐based nanofibres are non‐sensitizing, non‐allergic and non‐toxic and that it can be used as a peculiar wound healing material.Inspec keywords: polymer fibres, nanofibres, nanomedicine, biomedical materials, wounds, electrospinning, zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, X‐ray diffraction, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, thermal analysis, scanning electron microscopy, wetting, contact angle, toxicologyOther keywords: electrospun polyurethane nanofibres, soy protein nanofibres, wound dressing applications, electrospinning, nanofibre mat, soy protein isolate, zinc oxide nanoparticles, ciprofloxacin hydrochloride, X‐ray diffraction, Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, thermogravimetric analysis, scanning electron microscope, mechanical properties, universal testing machine, wettability, contact angle measurement, sessile drop test, nonsensitizing nanofibres, nonallergic nanofibres, nontoxic nanofibres, wound healing material, wavelength 300 nm to 350 nm, ZnO     

Age and domain specific usability analysis of opinion visualisation techniques

This study analysed the impact of age and domain knowledge on the usability of some of the state-of-the-art opinion visualisation techniques. A questionnaire survey was designed to ask the users’ level of agreement or disagreement about the selected opinion visualisation techniques against a set of information visualisation metrics. The data were collected by conducting seminars and using a web-based online questionnaire. We categorised participants (N?=?146) into three age groups (≤20 years: teenager; 21–30 years: young adults; >30: adults). According to domain knowledge, participants are classified into two groups, one having knowledge of human computer interaction (HCI users) and the other without this knowledge (non-HCI users). The collected data were analysed using an independent sample t-test and analysis of variance. It is concluded that there are significant differences between the perception of HCI and non-HCI users on visual appeal, understandability, user friendliness, intuitiveness, informativeness, usefulness, comprehensiveness, comparison ability, and pre-knowledge requirement. Moreover, age was found to be significant for visual appeal, comprehensiveness, intuitiveness, and pre-knowledge requirement.     

Surface treatment of plasticized poly(vinyl chloride) to prevent plasticizer migration

In this investigation, plasticized poly(vinyl chloride) (PVC) was treated with poly(azido acrylate)s to prevent plasticizer migration. This was achieved by modification of PVC sheets with poly(azido acrylate)s in a dichloromethane solution followed by irradiation under UV light. The surface‐modified PVC sheets with poly (azido acrylate)s were characterized with Fourier transform infrared spectroscopy and scanning electron microscopy analyses. The migration of the plasticizer was prevented to a large extent from modified PVC in comparison with unmodified PVC. The amount of plasticizer migration with respect to the irradiation time, incubation time, and number of dipping times was evaluated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Antioxidant Activity of Pink-Flesh Guava (Psidium guajava L.): Effect of Extraction Techniques and Solvents

The effect of commonly used techniques and solvents in the antioxidant activities of pink-flesh guava fruit were studied. The extraction techniques compared were homogenization, shaking, sonication, magnetic stirring, and maceration for 1, 2, and 3 days. The solvent systems used were methanol, ethanol, and acetone at three different concentrations (50%, 70%, and 100%) and with 100% distilled water. The antioxidant activity of the fruit was evaluated using Folin–Ciocalteu index, ferric-reducing antioxidant power assay, and 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity. Ultrasonic and homogenization were the best techniques to extract the antioxidant from guava fruit. Homogenization technique was found to be the most convenient exhaustive and time-saving extraction technique. Results showed that the extracting solvent significantly (P < 0.05) altered the antioxidant property estimations of pink-flesh guava fruit. Pure solvents were inefficient extraction media for antioxidant. Enhanced extraction yields were obtained from solvent containing higher water concentrations and 50% acetone is a recommended solvent for extracting antioxidants compounds from pink-flesh guava fruit. High correlations between phenolic compositions and antioxidant activities of pink-flesh guava extracts were observed. High levels of antioxidant activities were detected in pink-flesh guava, indicating that the fruit may serve as an excellent dietary source of natural antioxidants.     

Malaysian Facebookers: Motives and addictive behaviours unraveled

Malaysians were reported to have the most number of Facebook friends, spend more time on Facebook and might be addicted to Facebook as well. This paper explored Facebook usage pattern, motivations and psychological/behavioural factors affecting the users. A focus group study was first conducted to explore motives to use Facebook and symptoms related to excessive Facebook usage. The themes emerging from this were then used in addition to Uses and Gratifications theory and Brown’s Addiction framework to further explore Facebook usage pattern, motivations and behavioural issues among a large group of students. Results show that Malaysian students use Facebook actively, similar to other studies done worldwide. Factor analyses yielded five motives to use Facebook: Social Networking, Psychological Benefits, Entertainment, Self Presentation and Skill Enhancement. As for the behavioural symptoms, Salience, Loss of Control, Withdrawal and Relapse and Reinstatement emerged as the four main symptoms. These results show that in general Malaysian students use Facebook for similar motives as reported in literature. However, it is interesting to note that they also exhibited behavioural symptoms, such as Salience, Loss of Control, Withdrawal and Relapse and Reinstatement due to excessive Facebook usage.     

Quantum mechanical compact modeling of symmetric double-gate MOSFETs using variational approach

A physics-based analytical model for symmetrically biased double-gate (DG) MOSFETs considering quantum mechanical effects is proposed. Schrödinger's and Poisson's equations are solved simultaneously using a variational approach. Solving the Poisson and Schrödinger equations simultaneously reveals quantum mechanical effects (QME) that influence the performance of DG MOSFETs. The inversion charge and electrical potential distributions perpendicular to the channel are expressed in closed forms. We systematically evaluated and analyzed the potentials and inversion charges, taking QME into consideration, in Si based double gate devices. The effect of silicon thickness variation in inversion-layer charge and potentials are quantitatively defined. The analytical solutions provide good physical insight into the quantization caused by quantum confinement under various gate biases.     

Synthesis and characterisation of starch/agar nanocomposite films for food packaging application

In the present work cassava starch/agar Ag and ZnO nanocomposite films were prepared by the solution casting method. The structural, physical and antimicrobial properties of the nanocomposite films were studied as a function of the concentration of Ag and ZnO nanoparticles. The results of the thermogravimetric analysis showed 8–15% degradation of both the nanocomposite films at 150°C endorsing the thermal stability of the films. Scanning electron microscopic analysis reveals the uniform blending of Ag and ZnO nanoparticles with a starch/agar matrix with tiny waves like appearance on the surface. The incorporation of Ag and ZnO nanoparticles in the film was found to reduce the moisture content, water solubility and water vapour permeability with increase in the concentration of Ag and ZnO nanoparticles. The growth kinetics study of Pseudomonas aeruginosa and Staphylococcus aureus in the presence of Ag and ZnO blended nanocomposite films showed promising results especially against Gram‐negative P. aeruginosa. Thus, the film synthesised in the present study bears the potential to be used as active packaging material to prevent food from bacterial contamination and spoilage.Inspec keywords: casting, microorganisms, scanning electron microscopy, nanoparticles, food preservation, solubility, thermal analysis, zinc compounds, food processing industry, food products, thermal stability, permeability, antibacterial activity, food packaging, contaminationOther keywords: water vapour permeability, food packaging, solution casting method, structural properties, physical properties, antimicrobial properties, water solubility, agar nanocomposite film, starch nanocomposite film, Pseudomonas aeruginosa, Staphylococcus aureus, bacterial contamination prevention, spoilage prevention, scanning electron microscopic analysis, thermogravimetric analysis, temperature 150.0 degC, Ag, ZnO     

An analysis of drifts and nonlinearities in electrochemical impedance spectra

The response of an electrochemical reacting system to potential perturbations during electrochemical impedance spectrum measurement is investigated using numerical simulation. Electrochemical metal dissolution via an adsorbed intermediate species is analyzed and it is shown that applying the potential perturbation causes the average surface coverage to drift. For high frequency perturbations, the final value of the average surface coverage depends mainly on the kinetic parameters and the amplitude of the applied perturbation. Acquiring the data during the first few cycles of perturbations leads to an incorrect calculation of the impedance, particularly for large amplitude perturbations. Repeating the experiments will not identify this drift, while Kramers–Kronig Transform (KKT) can successfully detect this problem. The correct experimental methodology to overcome this effect and obtain the impedance spectra is also described. Another reaction with two adsorbed intermediates is also investigated and it is shown that in certain cases, the violations of linearity criteria can also be detected by KKT. The results illustrate the importance of validating the impedance data with KKT before further analysis.     

Achieving Energy Conservation by Cluster Based Data Aggregation in Wireless Sensor Networks

In Wireless Sensor Networks (WSN), one of the major issues is to maximize the network lifetime. Since all sensor nodes directly send the data to the Base station, the energy requirement is very high. This reduces the lifetime of the network. One of the solutions is to partition the network into various clusters which avoids direct communication. In this paper we propose an Energy efficient Cluster Based Data Aggregation (ECBDA) scheme for sensor networks. In this algorithm, Cluster members send the data only to its corresponding local cluster head, there by communication overhead is reduced. Data generated from neighboring sensors are often redundant and highly correlated. So the cluster head performs data aggregation to reduce the redundant packet transmission. In our approach, clusters are formed in a non-periodic manner to avoid unnecessary setup message transmissions. Re-clustering is performed only when CH needs to balance the load among the nodes. The simulation results show that our approach effectively reduces the energy consumption and hence the network lifetime is also increased.     

A semi-supervised approach in detecting sentiment and emotion based on digital payment reviews

The Journal of Supercomputing - This paper investigates the sentiment and emotion of digital payment application consumers using a hybrid approach consisting of both supervised and unsupervised...