Piezoelectricity of the Transmembrane Protein ba3 Cytochrome c Oxidase

Controlling the electromechanical response of piezoelectric biological structures including tissues, peptides, and amino acids provides new applications for biocompatible, sustainable materials in electronics and medicine. Here, the piezoelectric effect is revealed in another class of biological materials, with robust longitudinal and shear piezoelectricity measured in single crystals of the transmembrane protein ba₃ cytochrome c oxidase from Thermus thermophilus. The experimental findings from piezoresponse force microscopy are substantiated using a range of control measurements and molecular models. The observed longitudinal and shear piezoelectric responses of ≈ 2 and 8 pm V⁻¹, respectively, are comparable to or exceed the performance of commonly used inorganic piezoelectric materials including quartz, aluminum nitride, and zinc oxide. This suggests that transmembrane proteins may provide, in addition to physiological energy transduction, technologically useful piezoelectric material derived entirely from nature. Membrane proteins could extend the range of rationally designed biopiezoelectric materials far beyond the minimalistic peptide motifs currently used in miniaturized energy harvesters, and the finding of robust piezoelectric response in a transmembrane protein also raises fundamental questions regarding the molecular evolution, activation, and role of regulatory proteins in the cellular nanomachinery, indicating that piezoelectricity might be important for fundamental physiological processes.     

Characterization and antibacterial properties of nanoboron powders and nanoboron powder coated textiles

The antibacterial properties of boron-containing compounds are well known although there are limited studies available on the pure boron nanoparticles. In this paper, nanoboron particles are characterized in terms of their particle size, shape, stability and surface charge before and after their application onto textile surfaces to study their impact on bacterial activity. It was observed that the boron nanoparticles are effective in limiting the bacterial growth of both Gram-negative and positive species without requiring any stimulation to initiate the antibacterial action. In addition to the antibacterial functionality evaluation of the free boron nanoparticles, nanoboron coated textiles were also characterized and determined to change the wettability and surface charge of the textiles with a variable antimicrobial response to the different species. Consequently, we propose pure nanoboron as a new anti-bacterial agent that can function without external stimulation.     

N-3 Polyunsaturated Fatty Acids Modulate In-Vitro T Cell Function in Type I Diabetic Patients

In this work, we assessed the in-vitro effects of eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) (final concentration, 15 microM) on T cell blastogenesis, interleukin-2 and -4 (IL-2, IL-4) secretion, fatty acid composition and intracellular oxidative status in type I diabetic patients with or without complications. Con A stimulated lymphocyte proliferation, glucose uptake, intracellular reduced glutathione levels and catalase activity were lower in diabetics as compared to controls, regardless to the presence of complications. EPA and DHA diminished T-lymphocyte proliferation and IL-2 production but enhanced IL-4 secretion in both diabetic and control groups. No changes in the levels of reduced glutathione and in the activities of catalase and SOD were observed in control T cells cultured in the presence of EPA and DHA. However, in diabetic patients, addition of n-3 PUFA to culture induced an increase in T cell levels of reduced glutathione and hydroperoxide, and in activities of catalase and SOD. Low levels of arachidonic acid (C20:4n-6) were found in plasma membrane phospholipids of lymphocytes from diabetic patients compared to controls. Incubation of lymphocytes with EPA and DHA was associated with an incorporation of these fatty acids in membrane phospholipids. In conclusion, the beneficial effects of n-3 PUFA on T cell functions in type I diabetes could be attributed to their suppressive action and modulation of cytokine secretion, and to the improvement of intracellular oxidative status.     

A flexible receiver for CDMA multiuser communications

Code division multiple access (CDMA) capacity is limited by interference amongst users. The effect of this interference on receiver outputs depends on the users' signatures and the actual detector used in the receiver. A matched filter receiver is particularly sensitive to interference, whereas an optimum multiuser receiver is less sensitive but infeasible due to its exponential complexity. We propose a receiver structure that trades detection performance for reduced complexity. It can interpolate between the performances and complexities of these two receivers. Our detector uses a tree structure, and some of its special cases are the decision feedback detector, the decorrelating detector, and the optimal linear detector. We show that at equal complexity levels, a particular implementation of our detector outperforms these detectors. We also show that our approach can be used with a minimum-mean-square-error design criterion and coded CDMA transmission     

Analysis of the IAEA research reactor benchmark problem by the RETRAC-PC code

A basic approach to perform safety analysis of a nuclear research reactor consists in using deterministic methods to verify that the established acceptance criteria related to fuel integrity are fulfilled during all the stages of the facility lifetime. These methods should be validated against a large set of experimental and postulated transients. Since measured data are not easily available in the literature, the IAEA defined typical transients in a generic 10-MW MTR nuclear reactor core as a benchmark test for computational tools verification. In this framework, an assessment study of the coupled kinetic–thermal–hydraulic RETRAC-PC code is presented herein. The considered cases include the analysis of core dynamic under ramp positive reactivity insertion, and loss of flow transients. In general, the obtained results are satisfactory and agree with results obtained by other similar codes.     

Data hiding for multimedia personalization, interaction, andprotection

The advantages of digital media have opened up many new possibilities to hide data (information) within audio, image and video files. In order to provide copyright protection digital watermarking has been proposed as a means of identifying the owner or distributor of digital data. Data hiding and watermarking research builds on ideas and concepts developed in cryptography, communications theory, algorithm design, and signal processing. The data hiding problem is inherently more difficult than any of the problems that have traditionally been addressed in these fields. All data hiding algorithms combine and extend, in a sense, many of the solutions developed in these areas     

Phase Behavior of Poly(butyl acrylate) Networks in Nematic Liquid Crystal Solvents

Summary: This paper reports the phase behavior of photochemically crosslinked poly(butyl acrylate) networks in nematic liquid crystal (LC) solvents. The swelling properties are studied as a function of temperature for two low molecular weight nematic LCs, 4‐cyano‐4′‐pentylbiphenyl (5CB) and the eutectic mixture of cyanoparaphenylenes (E7). Chemically crosslinked polymer networks were formed by the UV radiation of initial solutions of the reactive monomer, butyl acrylate, a crosslinker (hexanediol diacrylate), and a photoinitiator. To obtain different network densities, the ratio of butyl acrylate to hexanediol diacrylate was varied prior to polymerization/crosslinking reactions. Immersion in an excess of the LC solvent allowed for the measurement of size increase by polarized optical microscopy in terms of temperature. Length, width, and diagonal ratios were calculated considering swollen to dry network states of the samples. In general, swelling leads to an increase in the network size by increasing the temperature with a significant dependence on the degree of crosslinking. A large shift in the swelling ratio was found in the vicinity of the nematic to isotropic transition temperatures of the LCs.

     

RELAP5/3.2 assessment against low pressure onset of flow instability in parallel heated channels

Best Estimate computer codes have been, so far, developed for safety analysis of nuclear power plants and were extensively validated against a large set of separate effects and integral test facilities experimental data relevant to such kind of reactors. Their application to research reactors is not fully straightforward. Modelling problems generally emerge when applying existing models to low pressure and more particularly to subcooled flow boiling situations. The objective of the present work is to investigate the RELAP5/3.2 system code capabilities in predicting phenomena that could be encountered under abnormal research reactor’s operating conditions. For this purpose, the separate effect related to the static onset of flow instability is investigated. The cases considered herein are the flow excursion tests performed at the Oak Ridge National Laboratory thermal hydraulic test loop (THTL) as well as some representative Whittle and Forgan (W & F) experiments. The simulation results are presented and the capabilities of RELAP5/Mod 3.2 in predicting this critical phenomenon are discussed.     

Cogan''s syndrome: a review of otologic management and 10-year follow-up of a pediatric case

Benign hereditary chorea is an uncommon inherited form of childhood chorea that can be mistaken for much more serious disorders, such as Huntington disease. The clinical manifestations of this condition are reviewed, emphasizing the differential diagnosis, treatment modalities, and evaluation of childhood chorea.