Some new negative-impedance convertors

Three new realisations of a negative impedance convertor are proposed. Two of them are of the voltage-inversion type, and the other is of the current-inversion type. In order to satisfy the necessary conditions required of a negative-impedance convertor, certain constraints are imposed on the choice of circuit elements. These conditions are briefly discussed. The proposed new circuits have not been tried out in practice.     

Effect of natural ageing on the dielectric properties of some synthetic rubber mixtures

The dielectric constant ε′ and dielectric loss ε″ have been investigated for SBR samples loaded with some white fillers and for perbunan rubber loaded with silica and carbon black in the frequency range from 60 to 10⁷ Hz at room temperature. The samples were exposed to normal weathering conditions for about five years. The results are compared with those obtained five years before and the differences are interpreted.     

On the performance of ENDF/B-VII.0 data for fast neutron fluence calculations

The newest release of the Evaluated Nuclear Data File, ENDF/B-VII.0, has recently become available, along with the announcement of its significant advances over previous versions. The older ENDF/B releases, however, have been assessed for numerous applications in the past and, as such, currently find wide application in the nuclear industry. An analysis of the influence of the recent upgrade in the data file is thus needed with respect to specific practical applications. The present technical note addresses the effects of modifications of the neutron cross-sections in the ENDF/B-VII.0 library, relative to the preceding ENDF/B-VI.8 release, on calculations of the fast neutron fluence accumulated in a PWR reactor pressure vessel, which is of direct relevance for the licensing and safe operation of nuclear power plants.     

Breaking an image encryption scheme based on Arnold map and Lucas series

Multimedia Tools and Applications - Recently, a novel image encryption based on Arnold scrambling and Lucas series has been proposed in the literature. The scheme design is based on...     

Optimisation of used nuclear fuel canister loading using a neural network and genetic algorithm

Neural Computing and Applications - This paper presents an approach for the optimisation of geological disposal canister loadings, combining high resolution simulations of used nuclear fuel...     

Application of swarm techniques to requirements tracing

We posit that swarm intelligence can be applied to effectively address requirements engineering problems. Specifically, this paper demonstrates the applicability of swarm intelligence to the requirements tracing problem using two techniques: a simple swarm algorithm and a pheromone swarm algorithm. The techniques have been validated using two real-world datasets from two problem domains. The simple swarm technique generated requirements traceability matrices between textual requirements artifacts (high-level requirements traced to low-level requirements, for example). When compared with a baseline information retrieval tracing method, the swarm algorithms showed mixed results. The swarms achieved statistically significantly results on one of the secondary measurements for one dataset compared with the baseline method, lending support for continued investigation into swarms for tracing.     

Security analysis of an audio data encryption scheme based on key chaining and DNA encoding

Multimedia Tools and Applications - Fairly recently, a new audio encryption scheme has been proposed. The cryptosystem is based on a substitution-permutation algorithm using DNA encoding. The...     

Biocontrol of Listeria monocytogenes in a model cultured milk (lben) by in situ bacteriocin production from Lactococcus lactis ssp. lactis

Bacteriocin‐producing (Bac⁺) Lactococcus lactis ssp. lactis CCMM/IAV/BK1 isolated from traditional lben was used in the preparation of lben from pasteurized milk to assess its potential inhibitory activity against Listeria monocytogenes ATCC 7644. Production of bacteriocin (arbitrary units, AU) in MRS broth fortified with yeast extract (MRSY) in a fermentor under controlled and uncontrolled pH conditions was also investigated. This Bac⁺ strain yielded about 35 times more bacteriocin when the pH was maintained constant at 6.5 than under varying pH conditions. To test the effect of in situ bacteriocin production against L. monocytogenes, lben was made from cow's milk artificially contaminated with approximately 10⁷ cfu/mL and fermented with a mixed mesophilic starter culture consisting of the lactococcal Bac⁺ organism and Lc. lactis ssp. lactis biovar diacetylactis 66, a diacetyl‐producing strain, in a ratio of 1 : 1. Numbers of L. monocytogenes were monitored during fermentation and storage of lben at refrigeration temperature (c. 7°C) for up to 6 days. Performances of the Bac⁺ starter were compared to those of an isogenic Bac^? derivative strain obtained from the Bac⁺ starter by curing with ethidium bromide. The results showed that the amount of L. monocytogenes decreased to below the detectable level in a 1‐mL sample within 24 h of storage at 7°C in lben fermented with the Bac⁺ starter culture. On the contrary, L. monocytogenes survived for 6 days of storage at 7°C in lben made with the Bac^? starter. The Bac⁺ wild strain of the starter studied could be adequately used to produce lben or similar indigenous fermented milks of improved hygienic quality on an industrial scale. Alternatively, it could be used as an adjunct in minimally processed products or in products obtained from raw milk to add a safety factor.     

The Role of Dietary Advanced Glycation End Products in Metabolic Dysfunction

Advanced glycation end products (AGEs) are a heterogeneous group of molecules produced, non‐enzymatically, from the interaction between reducing sugars and the free amino groups of proteins, nucleic acids, and lipids. AGEs are formed as a normal consequence of metabolism but can also be absorbed from the diet. They have been widely implicated in the complications of diabetes affecting cardiovascular health, the nervous system, eyes, and kidneys. Increased levels of AGEs are also detrimental to metabolic health and may contribute to the metabolic abnormalities induced by the Western diet, which is high in processed foods and represents a significant source of AGEs. While increased AGE levels are a consequence of diabetic hyperglycaemia, AGEs themselves activate signaling pathways, which compromise insulin signaling and pancreatic β‐cell function, thus, contributing to the development of type 2 diabetes mellitus (T2DM). Furthermore, AGEs may also contribute to the obesogenic effects of the Western diet by promoting hypothalamic inflammation and disrupting the central control of energy balance. Here, the role of dietary AGEs in metabolic dysfunction is reviewed with a focus on the mechanisms underpinning their detrimental role in insulin resistance, pancreatic β‐cell dysfunction, hypothalamic control of energy balance, and the pathogenesis of T2DM and obesity.     

Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO_10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering.