Secure FSM-based arithmetic codes

Recently, arithmetic coding has attracted the attention of many scholars because of its high compression capability. Accordingly, in this paper, a method that adds secrecy to this well-known source code is proposed. Finite state arithmetic code is used as source code to add security. Its finite state machine characteristic is exploited to insert some random jumps during source coding process. In addition, a Huffman code is designed for each state to make decoding possible even in jumps. Being prefix-free, Huffman codes are useful in tracking correct states for an authorized user when he/she decodes with correct symmetric pseudo-random key. The robustness of our proposed scheme is further reinforced by adding another extra uncertainty by swapping outputs of Huffman codes in each state. Several test images are used for inspecting the validity of the proposed Huffman finite state arithmetic coding (HFSAC). The results of several experimental key space analyses, statistical analyses, key and plaintext sensitivity tests show that HFSAC with a little effect on compression efficiency provides an efficient and secure method for real-time image encryption and transmission.     

Phase noise characterization of oscillators through Ito calculus

Recent phase noise analysis techniques of oscillators mainly rely on solving a stochastic differential equation governing the phase noise process. This equation has been solved in the literature using a number of mathematical tools from probability theory like deriving the Fokker–Planck equation governing the phase noise probability density function. Here, a completely different approach for solving this equation in presence of white noise sources is introduced that is based on the Ito calculus for stochastic differential equations. Time‐domain analytical expressions for the correlation of the noisy variables of the oscillator are derived that in asymptotically large times give the steady‐state stochastic correlations as well as the power spectral densities of the variables. The validity of the new approach is verified by comparing its results against extensive Monte‐Carlo simulations. This approach is applied to an oscillator with a dielectric resonator at 4.127 GHz, and a very good agreement between its results with those of the Monte‐Carlo simulations and the previous approaches is observed. Copyright © 2014 John Wiley & Sons, Ltd.     

Cloud point preconcentration and flame atomic absorption spectrometry: application to the determination of manganese in milk and water samples

Cloud point extraction has been used for preconcentration of trace amount of manganese. The analyte was complexed with 1-(2-pyridylazo)-2-naphtol (PAN) and Triton X-114 was added as surfactant. After phase separation, based on the cloud point of the mixture, and dilution of the surfactant-rich phase with methanol, the enriched analyte was determined by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, enhancement factor of 49.1 was obtained. The detection limit was 0.39 ng ml⁻¹ for manganese. The proposed method was applied to the determination of manganese in milk and water samples.     

Impact of fruit processing methods on DNA extraction from transgenic frozen banana products

Isolation of high yield and quality of genomic DNA is paramount for ensuring confidence in molecular analyzing food. This study evaluated five different DNA extraction procedures based on laboratory protocols and commercial kits for their efficiency and also assessed the impact of processing procedures on the DNA degradation in various frozen banana products such as frozen-sliced banana, frozen banana puree, frozen plantain banana, and freeze-dried banana powder. The purity and concentration of DNA obtained from the samples were evaluated by spectrophotometric and gel electrophoresis analysis. Of the various extraction procedures, we applied modified protocols that allow for effective extraction of DNA from banana. This protocol derived from traditional cetyltrimethylammonium bromide method with modifications that allowed removing unwanted polyphenols and polysaccharides. The results confirm that a profound impact on DNA degradation was seen during the processing of banana products, DNA could still be reliably quantified by real-time PCR. Furthermore, frying resulted in further degradations and drying resulted in the most severe changes. It was noted that in different frozen banana products, nopaline synthase fragment is most stable followed by cauliflower mosaic virus 35S and NPTII gene.     

Antioxidant activity of some edible plants of the Turkmen Sahra region in northern Iran

The antioxidant properties of 10 edible plants of the Turkmen Sahra region in Golestan province in northern Iran, including Allium paradoxum, Allium rubellum, Foeniculum vulgare, Mentha longifolia, Origanum vulgare, Prunus divaricata, Rubus sanctus, Rumex tuberosus, Satureja mutica and Spinacia turkestanica were evaluated by four different methods; free radical scavenging using 2,2-diphenyl-1-picrylhydrazyl (DPPH), evaluation of xanthine-oxidase activity, inhibition of lipid peroxidation by the ferric thiocyanate method, and the deoxyribose degradation assay. All species tested except A. paradoxum and P. divaricata showed antioxidant activity at least in one assay.     

Facile synthesis of Co3O4 nanoparticles from a novel tetranuclear cobalt(III) complex. Application as efficient electrocatalyst for oxygen evolution reaction in alkaline media

A tetranuclear cobalt complex [Co₄^III(L′)₆] was synthesized by the direct reaction of cobalt(II) acetate with a N₂S₂ Schiff base ligand H₂L containing a disulfide bond under aerobic conditions {H₂L = 2,2′-bis(2-hydroxynaphthyliminobenzyl)disulfide}. The X-ray crystal structure of [Co₄^III(L′)₆] indicates reductive disulfide bond scission of H₂L upon reaction with Co²⁺ to give [L^′]^2–. Furthermore, cobalt oxide nanoparticles of about 30 nm size were synthesized by thermal decomposition of [Co₄^III(L′)₆] as a precursor. The Co₃O₄ nanoparticles were characterized by XRD, FE-SEM, TEM, and FT-IR spectroscopy. The electrocatalytic activity of the resulting oxide was examined in oxygen evolution reaction (OER) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in 1.0 mol L^?1 KOH. The NPs displays efficient electrocatalytic activity for oxygen evolution reaction with a current density of 10.0 mA cm^?2 at 1.65 V, good onset potential of 1.52 V vs. RHE and small Tafel slope of 44 mV dec^?1.     

Multistage decoding for an internally coded fibre-optic time-hopping/optical code division multiple access communication system

A multistage decoder for the internally convolutionally coded fibre-optic time-hopping code division multiple access system recently introduced is considered. In this system, the decoder consists of several stages. The first stage is implemented using one of the single-user decoders introduced. The following stages are maximum likelihood (ML) decoders each of which use the decisions made by the previous stage. The performance of the proposed decoder is evaluated by a Monte Carlo simulation. Numerical results show that a multistage decoder with only two stages greatly outperforms the single-stage decoder with negligible increase in complexity. The authors also derive the Chernoff bound for the ML decoder with known interference, which is the ultimate performance of the multistage decoder.     

Mixed logit analysis of bicyclist injury severity resulting from motor vehicle crashes at intersection and non-intersection locations

Standard multinomial logit (MNL) and mixed logit (MXL) models are developed to estimate the degree of influence that bicyclist, driver, motor vehicle, geometric, environmental, and crash type characteristics have on bicyclist injury severity, classified as property damage only, possible, nonincapacitating or severe (i.e., incapacitating or fatal) injury. This study is based on 10,029 bicycleinvolved crashes that occurred in the State of Ohio from 2002 to 2008. Results of likelihood ratio tests reveal that some of the factors affecting bicyclist injury severity at intersection and non-intersection locations are substantively different and using a common model to jointly estimate impacts on severity at both types of locations may result in biased or inconsistent estimates. Consequently, separate models are developed to independently assess the impacts of various factors on the degree of bicyclist injury severity resulting from crashes at intersection and non-intersection locations.Several covariates are found to have similar impacts on injury severity at both intersection and non-intersection locations. Conversely, six variables were found to significantly influence injury severity at intersection locations but not non-intersection locations while four variables influenced bicyclist injury severity only at non-intersection locations. In crashes occurring at intersection locations, the likelihood of severe bicyclist injury increases by 14.8 percent if the bicyclist is not wearing a helmet, 82.2 percent if the motorist is under the influence of alcohol, 141.3 percent if the crash-involved motor vehicle is a van, 40.6 percent if the motor vehicle strikes the side of the bicycle, and 182.6 percent if the crash occurs on a horizontal curve with a grade. Results from non-intersection locations show the likelihood of severe injuries increases by 374.5 percent if the bicyclist is under the influence of drugs, 150.1 percent if the motorist is under the influence of alcohol, 53.5 percent if the motor vehicle strikes the side of the bicycle and 99.9 percent if the crash-involved motor vehicle is a heavy-duty truck.     

How Can We Improve the Vaccination Response in Older People? Part II: Targeting Immunosenescence of Adaptive Immunity Cells

The number of people that are 65 years old or older has been increasing due to the improvement in medicine and public health. However, this trend is not accompanied by an increase in quality of life, and this population is vulnerable to most illnesses, especially to infectious diseases. Vaccination is the best strategy to prevent this fact, but older people present a less efficient response, as their immune system is weaker due mainly to a phenomenon known as immunosenescence. The adaptive immune system is constituted by two types of lymphocytes, T and B cells, and the function and fitness of these cell populations are affected during ageing. Here, we review the impact of ageing on T and B cells and discuss the approaches that have been described or proposed to modulate and reverse the decline of the ageing adaptive immune system.