Preparation and characterization of acrylonitrile‐ethyl methacrylate copolymers and the effect of LiClO4 salt on electrical properties of copolymer films

Copolymers of poly(acrylonitrile‐co‐ethyl methacrylate), P(AN‐EMA), with three different EMA content and parent homopolymers were synthesized by emulsion polymerization. The chemical composition of copolymers were identified by FTIR, ¹H‐NMR and ¹³C‐NMR spectroscopy. The thermal properties of copolymers were modified by changing the EMA content in copolymer compositions. Various amounts of LiClO₄ salt loaded (PAN‐co‐PEMA) copolymer films were prepared by solution casting. The dielectric properties of these films at different temperatures and frequencies were investigated. It was found that the dielectric constant and ac‐conductivity of copolymer films were strongly influenced by the salt amounts and EMA content in copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Symmetry breaking in a plasmonic metamaterial at optical wavelength

We numerically study the effect of structural asymmetry in a plasmonic metamaterial made from gold nanowires. It is reported that optically inactive (i.e., optically dark) particle plasmon modes of the symmetric wire lattice are immediately coupled to the radiation field, when a broken structural symmetry is introduced. Such higher order plasmon resonances are characterized by their subradiant nature. They generally reveal long lifetimes and distinct absorption losses. It is shown that the near-field interaction strongly determines these modes.     

Hydrogen sensing properties of ZnO nanorods: Effects of annealing,temperature and electrode structure

In this study, the hydrogen (H₂) sensing properties of vertically aligned zinc oxide (ZnO) nanorods were investigated depending on annealing, Pd coating, temperature and electrode structure. ZnO nanorods were fabricated by using hydrothermal method on a glass substrate and an indium tin oxide (ITO) coated glass substrate. In order to determine the effects of annealing on the H₂ sensor performance, the nanorods were heated at 500 °C in dry air. H₂ sensing measurements were done in the temperature range of 25–200 °C. It was found that, the sensor response of Pd coated ZnO nanorods were much higher than the un-coated nanorods due to the catalytic effect of Pd thin film. Moreover, the un-annealed samples showed better sensor response than the annealed samples due to the number of oxygen deficiency. In addition, the lateral electrode structure showed higher sensor response than the sandwich electrode structure.     

Xanthan gum production under different operational conditions by <Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv <Emphasis Type="Italic">vesicatoria</Emphasis> isolated from pepper plant

The influence of operational conditions (pH, stirrer speed, and temperature) used in the process of xanthan production by Xanthomonas axonopodis pv vesicatoria (XCVA3-1) isolated from pepper plant were evaluated through yield of xanthan and compared with control strain Xanthomonas campestris NRRL-B 1459. Different conditions used during the fermentation affected the xanthan production. In this study the best combination of yield was obtained, reaching 1.325 g/100 mL with the use of pH 7.0, 30°C, and 250 rpm during fermentation. Increased yield of xanthan production can be obtained at high agitation values, with the maximum at 400 rpm. Higher yields of gum production can be obtained at 30°C and the optimum pH was found 7.0. This results were similar for the X. campestris NRRL-B 1459.     

Evaluation of acrylamide and selected parameters in some Turkish coffee brands from the Turkish market

The purpose of this study was to measure acrylamide (AA) levels and selected parameters of different traditional Turkish coffees. AA, 5-hydroxymethylfurfural (HMF), total reducing sugar, protein, pH, moisture, dry matter (DM) as well as ash, caffeine and soluble solids content (SSC) in DM, L*, a*, b* colour parameters of coffee samples were determined and the correlation between AA level and these parameters were investigated. A total of 36 coffee samples (20 Turkish, 8 Dibek and 8 Terebinth coffee) from the Turkish market were examined. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated for the detection and quantitation of AA in coffee samples. The calibration curve was linear (R² ≥ 0.999) over the range of 30–1000 μg kg^?1. The limit of detection (LOD) and limit of quantification (LOQ) were found as 4.6 μg kg^?1 and 15.5 μg kg^?1, respectively. The amounts of AA in analysed coffee samples were in the range 31.1 ± 0.6 to 323.4 ± 5.4 µg kg^?1. The highest mean AA levels were found in Terebinth coffees (240.3 μg kg^?1) followed by Turkish coffees (204.3 µg kg^?1) and then Dibek coffees (78.6 µg kg^?1). No tested Turkish coffee samples had an AA concentration above the indicative value (450 µg kg^?1) for roast coffee recommended by the European Commission (EC) in 2011. In addition, a strong positive correlation was found between HMF values and AA amounts of selected coffee types.     

Glycoalkaloids (α-chaconine and α-solanine) contents of selected Pakistani potato cultivars and their dietary intake assessment

Glycoalkaloids (α-solanine and α-chaconine) are naturally occurring toxic compounds in potato tuber (Solanum tuberosum L.) that cause acute intoxication in humans after their consumption. Present research was conducted to evaluate α-chaconine, α-solanine, and total glycoalkaloids (TGAs) contents in the peel and flesh portions by high-performance liquid chromatography method in selected Pakistani potato cultivars. The α-solanine content varies 45.98 ± 1.63 to 2742.60 ± 92.97 mg/100 g of dry weight (DW) in peel and from 4.01 ± 0.14 to 2466.56 ± 87.21 mg/100 g of DW in flesh. Similarly, α-chaconine content varied from 4.42 ± 0.16 to 6818.40 ± 211.07 mg/100 g of DW in potato peel and from 3.94 ± 0.14 to 475.33 ± 16.81 mg/100 g DW in flesh portion. The TGA concentration varied from 177.20 ± 6.26 to 5449.90 ± 192.68 mg/100 g of DW in peel and from 3.08 ± 0.11 to 14.69 ± 0.52 mg/100 g of DW in flesh portion of all the potato cultivars tested. All the potato cultivars contained lower concentration of TGA than the limits recommended as safe, except 2 cultivars, that is FD8-3 (2539.18 ± 89.77 mg/100 g of DW) and Cardinal (506.16 ± 17.90 mg/kg). The dietary intake assessment of potato cultivars revealed that Cardinal, FD 35-36, FD 8-3, and FD 3-9 contained higher amount of TGA in whole potato, although FD 8-3 only possessed higher content of TGA (154.93 ± 7.75) in its flesh portion rendering it unfit for human consumption. Practical Application: This paper was based on the research conducted on toxic compounds present in all possible potato cultivars in Pakistan. Actually, we quantify the toxic compounds (glycoalkaloids) of potato cultivars through HPLC and their dietary assessment. This paper revealed safety assessment and their application in food industries especially potato processing.     

The effect of ultrasonic treatments on turbidity,microbial load,and polyphenol oxidase (PPO) activity of plum nectar

This study examined the effects of ultrasound on several quality parameters of plum nectars, such as turbidity, microbial load, PPO activity, phenolic content, and physicochemical quality. The ultrasonic treatment was applied to the plum nectars at different treatment temperatures (40, 50, 60, and 70?°C) and durations (2.5, 5, 7.5, and 10 min). Ultrasound processing caused a significant increase in the turbidity level and stability of the plum nectars, which were correlated with increases in treatment temperature and duration. Similar effects were also observed in reduction of microbial load. Ultrasonic treatments at 7.5 min at 60?°C and 5 min at 70?°C reduced the total yeast and mold counts (<?1 log cfu/mL). The total mesophilic-aerobic microorganism (TMAB) count was also reduced by up to 2 log. The maximum inactivation of polyphenol oxidase (PPO) was ~46?% at 70?°C. No dramatic trends were observed for the pH, brix, and the total phenolic compound content of the plum nectar, while the flavonoid content dramatically increased. The ultrasonic treatment caused a slight positive color change by increasing the L* value of the plum nectars. In conclusion, the ultrasonic treatment was important process for increasing the turbidity quality and for inactivation of yeasts and molds, but it was not effective at inactivating the PPO enzyme.     

Antibiotic susceptibility patterns of Enterococcus strains isolated from Turkish Tulum cheese

The aim of this study was to detect the plasmid profiles, haemolytic activity and antibiotic susceptibility patterns of 47 Enterococcus strains isolated from Turkish Tulum cheese. Enterococcus strains were found to comprise 1–9 plasmids with molecular weight from 2.0 to 47.6 kb. None of the Enterococcus strains displayed haemolytic activity. The Enterococcus strains were found mostly resistant to tetracycline (30 μg) followed by high‐level streptomycin (300 μg). The Enterococcus faecalis strains were found to be highly resistant to antibiotics than Enterococcus faecium and Enterococcus durans strains. In total, 4.3% of the strains exhibited multiple antibiotic resistance patterns.     

Securing Cloud Storage by Remote DataIntegrity Check with Secured Key Generation

In recent decades, a number of protocols for Remote data integrity checking (RDIC) have been proposed.Identity (ID) based RDIC protocols are constructed to guarantee cloud data integrity and data privacy. The known protocols for RDIC always assume that the Private key generator (PKG) is a trusted one, but in real-world applications by corrupt PKG, malicious Cloud server (CS) can easily cheat the third party auditor that the data owner's outsourced data are kept safe through the data has been deleted or altered. In this paper, we explore the novel model of RDIC with untrusted PKG and malicious CS, by employing the partial key method and Authentication, authorization, accounting (AAA) service. We construct a new ID-based RDIC, which provides the ID revocation and key updation. The experimental evaluations show that our scheme is more efficient than known ones.