Zero–Hopf bifurcation in a hyperchaotic Lorenz system

We characterize the zero–Hopf bifurcation at the singular points of a parameter codimension four hyperchaotic Lorenz system. Using averaging theory, we find sufficient conditions so that at the bifurcation points two periodic solutions emerge and describe the stability of these orbits.     

Plasma Modification of Surface Wettability and Morphology for Optimization of the Interactions Involved in Blood Constituents Spreading on Some Novel Copolyimide Films

Novel copolyimides (cPIs) based on 3,3??,4,4??-benzophenonetetracarboxylic dianhydride, 4,4??-diaminodiphenylmethane (DDM) and 1,6-diaminohexane (DAH) were synthesized. Their surface wettability was improved by plasma enhancement of polar component contribution to surface tension from 10 to 50?%. Interfacial energy reduction up to 2.07?C2.95?mN/m was depicted in spreading work values that reveal the manner in which cPIs interact with blood constituents. The results showed that by increasing of the aliphatic DAH content in the polymer chain, the rejection of platelets is higher, prohibiting thrombosis and favoring cohesion with plasma proteins. The different water sorptions of the samples were evaluated by considering their morphologies and chemical affinities to water. When DAH prevails to DDM, water sorption capacity is lowered from 6.36 to 4.96?%?db, presumably due to a higher chain packing efficiency. Atomic force microscopy data revealed that surface roughness is <8?nm for all polymers, even after plasma treatment, preventing clot formation.     

Synthesis of Enantiopure Sulfonimidamides and Elucidation of Their Absolute Configuration by Comparison of Measured and Calculated CD Spectra and X‐Ray Crystal Structure Determination

Straightforward syntheses of enantiopure N‐benzoyl‐ and N‐tert‐butyloxycarbonyl‐protected sulfonimidamides, which can be used as building blocks in newly designed catalysts, are presented. Key synthetic step is a dynamic resolution of a racemic sulfinic acid sodium salt. All subsequent transformations proceed stereospecifically. The absolute configurations at the sulfur atoms of both sulfonimidamides were determined by comparison of measured and calculated CD spectra. An X‐ray crystal structure determination of a sulfonimidoylguanidine derivative confirmed this result.     

Microfluidics in macro-biomolecules analysis: macro inside in a nano world

Use of microfluidic devices in the life sciences and medicine has created the possibility of performing investigations at the molecular level. Moreover, microfluidic devices are also part of the technological framework that has enabled a new type of scientific information to be revealed, i.e. that based on intensive screening of complete sets of gene and protein sequences. A deeper bioanalytical perspective may provide quantitative and qualitative tools, enabling study of various diseases and, eventually, may offer support for the development of accurate and reliable methods for clinical assessment. This would open the way to molecule-based diagnostics, i.e. establish accurate diagnosis and disease prognosis based on identification and/or quantification of biomacromolecules, for example proteins or nucleic acids. Finally, the development of disposable and portable devices for molecule-based diagnosis would provide the perfect translation of the science behind life-science research into practical applications dedicated to patients and health practitioners. This review provides an analytical perspective of the impact of microfluidics on the detection and characterization of bio-macromolecules involved in pathological processes. The main features of molecule-based diagnostics and the specific requirements for the diagnostic devices are discussed. Further, the techniques currently used for testing bio-macromolecules for potential diagnostic purposes are identified, emphasizing the newest developments. Subsequently, the challenges of this type of application and the status of commercially available devices are highlighted, and future trends are noted.     

An Extension of the Weak Law of Large Numbers for Exchangeable Sequences

We prove an extension of the Kolmogorov-Feller weak law of large numbers for exchangeable sequences, by relaxing the finite mean condition therein.     

On the Kolmogorov–Feller law for exchangeable random variables

We prove a Kolmogorov–Feller weak law of large numbers for exchangeable sequences, under a second order hypothesis on the truncated mixands.     

Room-temperature SiGe light-emitting diodes

In the present paper the electroluminescence of PIN diodes with either strained SiGe/Si or Ge islands in the i-region has been investigated experimentally and by quantitative modelling. The modelling helped to improve the diode structure. Consequently, diodes with strained Si_0.80Ge_0.20 could be improved so as to reveal emission up to room temperature, if the thickness was high enough. To overcome the thickness limitation due to plastic relaxation, we used selective epitaxy on small areas. We also present results for diodes with Ge islands in the active region. The internal quantum efficiency of light emitting diodes with strained SiGe was at room temperature 10⁻⁴, while diodes with islands emitted ten times less light.     

Microorganism response to atmospheric pressure helium plasma DBD treatment

The effect of an atmospheric pressure plasma dielectric barrier discharge on some microorganisms was investigated, due to the possible extent of plasma applications in controlling microbial contamination. The present investigation involved both Gram-positive and Gram-negative germs – bacteria and yeasts – treated in helium plasma (asymmetric dielectric barrier discharge) for various time durations between 25 s and 100 s. Circular growth inhibition zones were measured for two distances between the discharge electrodes, the correlations with the plasma treatment time being analyzed. Differences between the sensitivities of the four tested microorganisms to helium plasma in open atmosphere were discussed.