Analytical investigation of a four-variable model of the BZ reaction

It is proved analytically that the four-variable model reported in the preceding paper [1] has a unique stationary solution for each set of rate constants. An upper and a lower boundary for the stationary concentrations are established.

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Experiment on the optical tunneling process of electrons from a gold surface induced by mode-locked CO2 laser pulse trains

Using intense mode-locked CO₂ laser pulse trains we verified the occurrence of the laser-induced, new-type dynamic optical tunneling of electrons from a gold surface. The results are in accordance with the theoretical predictions and our previous experiments carried out for both atoms and gold surface using single longer (ns) CO₂ laser pulses. Unknown properties of the development of the CO₂ laser train are revealed based on our higher-order coherence detection of electron emission.     

Influence of the carrier-envelope phase of few-cycle pulses on ponderomotive surface-plasmon electron acceleration

Control over basic processes through the electric field of a light wave can lead to new knowledge of fundamental light-matter interaction phenomena. We demonstrate, for the first time, that surface-plasmon (SP) electron acceleration can be coherently controlled through the carrier-envelope phase (CEP) of an excitation optical pulse. Analysis indicates that the physical origin of the CEP sensitivity arises from the electron's ponderomotive interaction with the oscillating electromagnetic field of the SP wave. The ponderomotive electron acceleration mechanism provides sensitive (nJ energies), high-contrast, single-shot CEP measurement capability of few-cycle laser pulses.     

Effects of potassium on the adsorption of methanol on β-Mo2C(001) surface

We have studied the effect of K on the adsorption of methanol on the β-Mo₂C(001) surface and compared our experimental data with theoretical calculations. We have also performed high resolution electron energy loss spectroscopy (HREELS) (LK, ELS3000). For calculations we used the density functional theory under the VASP implementation. The most favorable sites for methanol adsorption are on top of a Mo atom in the clean surface and on top of a K atom in the pre-dosed surface. The changes in the work function fit our model as the surface withdraws charge from the adsorbate. The changes in the computed vibrational frequencies also agree with the HREELS results at very low coverage. The C–O bond distance increases while the O–H bond decreases making a C–O bond breakage a possibility on K covered surfaces.     

The universal theta divisor over the moduli space of curves

By computing the class of the universal antiramification locus of the Gauss map, we obtain a complete birational classification by Kodaira dimension of the universal theta divisor over the moduli space of curves.     

A recursive least-squares algorithm for pairwise comparison matrices

Pairwise comparison matrices are commonly used for setting priorities among competing objects. In a leading decision making method called the analytic hierarchy process the principal right eigenvector components represent the weights of the alternatives. The direct least-squares method extracts the weight vector by first finding a rank-one matrix which minimizes the Euclidean distance from the original ratio matrix. We develop a recursive least-squares algorithm and reveal a striking correspondence between these two approaches for these matrices. The recursion applies for merely positive matrices also. We prove that a convergent iteration leads to matrices by which the Perron-eigenvectors and the Perron approximation of the original matrix may be produced. We show that certain useful properties of the recursion advance the development of reliable measures of perturbations of transitive matrices. Numerical analysis is included for a macroeconomic problem taken from the literature.     

The Nano-Jackhammer effect in probing near-surface mechanical properties

Because of its ease of implementation and insensitivity to indenter drift, dynamic indentation techniques have been frequently used to measure mechanical properties of bulk and thin film materials as a function of indenter displacement. However, the actual effect of the oscillating tip on the material response has not been examined. Recently, it has been shown that the oscillation used with dynamic indentation techniques alters the measured hardness value of ductile metallic materials, especially at depths less than 200 nm. The alteration in the hardness is due to the added energy associated with the oscillation which assists dislocation nucleation. Atomistic simulations on nickel thin films agree with experiments that more dislocations are nucleated during dynamic indents than with quasi-static indents. Through the analysis of quasi-static and dynamic indents made into nickel single crystals and thin films, a theory to describe this phenomenon is presented. This is coined the Nano-Jackhammer effect, a combination of dislocation nucleation and strain rate sensitivity caused by indentation with a superimposed dynamic oscillation.     

Complexation of hydroxamate-based siderophores with cobalt(II/III): growth inhibitory effect of cobalt(III)-desferricoprogen complex on fungi

Solution equilibrium results for Co(II) and Co(III) complexes of two natural hydroxamate-based siderophores, the exocyclic desferricrocin (DFR) and the endocyclic triacetylfusarinine (TAF) are presented. The three hydroxamate chelating functions of TAF were found to complete the octahedral coordination sphere of a Co(II) ion in stepwise processes, but following the coordination of two hydroxamates of DFR practically in one step, the third function, most probably because of sterical reasons, remained uncoordinated. A comparison with corresponding results for the previously studied acyclic desferrioxamine B (DFB) and desferricoprogen (DFC) provided some information about the effects of the molecular framework of siderophores on their cobalt-binding ability. The oxidation of the central metal ion under basic conditions and investigation of the cobalt(III) complexes by cyclic voltammetry were also made. Compared to Fe(III), by several orders of magnitude, higher stability complexes were formed with Co(III). The possibility of any effect of the Co(III)-siderophore complex on microbial Fe(III) uptake was tested by investigation of the antifungal effect of Co(III)-DFC in comparison with that of CoCl₂ on two fungi cultures, Penicillium brevicompactum and Aspergillus fumigatus.     

Biomedical Applications of Translational Optical Imaging: From Molecules to Humans

Light is a powerful investigational tool in biomedicine, at all levels of structural organization. Its multitude of features (intensity, wavelength, polarization, interference, coherence, timing, non-linear absorption, and even interactions with itself) able to create contrast, and thus images that detail the makeup and functioning of the living state can and should be combined for maximum effect, especially if one seeks simultaneously high spatiotemporal resolution and discrimination ability within a living organism. The resulting high relevance should be directed towards a better understanding, detection of abnormalities, and ultimately cogent, precise, and effective intervention. The new optical methods and their combinations needed to address modern surgery in the operating room of the future, and major diseases such as cancer and neurodegeneration are reviewed here, with emphasis on our own work and highlighting selected applications focusing on quantitation, early detection, treatment assessment, and clinical relevance, and more generally matching the quality of the optical detection approach to the complexity of the disease. This should provide guidance for future advanced theranostics, emphasizing a tighter coupling—spatially and temporally—between detection, diagnosis, and treatment, in the hope that technologic sophistication such as that of a Mars rover can be translationally deployed in the clinic, for saving and improving lives.