Development of a chemiluminescent optical fiber immunosensor to detect Streptococcus pneumoniae antipolysaccharide antibodies

A chemiluminescent-based optical fiber immunosensor was developed for the detection of antipneumococcal antibodies. This was accomplished by developing a different chemical procedure utilizing 3-aminopropyl trimethoxysilane and cyanuric chloride to conjugate pneumococcal cell wall polysaccharides to the optical fiber tips, and by improving the sensitivity of the photodetection system. The lowest titer of antipneumococcal antibodies detected by the optical fiber was at a 1:819,200 dilution. The lowest corresponding value by standard enzyme-linked immunosorbent assay was at a 1:98,415 dilution. It was concluded that the optical immunosensor system is an accurate and sensitive method to detect antipneumococcal antibodies and may be an adequate tool to monitor antibodies in specimens such as saliva and urine.     

Irreducible factorizations of rationalq-parameter matrices

This paper considers rational q-parameter matrices (i.e., matrices the entries of which are ratios of scalar polynomials in q variables) and extends the previous results of the authors. Bibliography: 8 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 248, 1998, pp. 147–164. Translated by V. N. Kublanovskaya.     

Damping of large-amplitude solitary waves

We consider the damping of large-amplitude solitary waves in the framework of the extended Korteweg-de Vries equation (that is, the usual Korteweg-de Vries equation supplemented with a cubic nonlinear term) modified by the inclusion of a small damping term. The damping of a solitary wave is studied for several different forms of friction, using both the analytical adiabatic asymptotic theory and numerical simulations. When the coefficient of the cubic nonlinear term has the opposite sign to the coefficient of the linear dispersive term, the extended Kortweg-de Vries equation can support large-amplitude “thick” solitary waves. Under the influence of friction, these “thick” solitary waves decay and may produce one or more secondary solitary waves in this process. On the other hand, when the coefficient of the cubic nonlinear term has the same sign as the coefficient of the linear dispersive term, but the opposite sign to the coefficient of the quadratic nonlinear term, the action of friction may cause a solitary wave to decay into a wave packet.     

Spatially-uniform temporal recompression of intense femtosecond optical pulses

A specially designed telescope with defocusing lens and off-axis parabolic mirror, which is working as a nonlinear element and producing self-phase modulation, was implemented for intense (3.1?TW/cm²) Fourier Transform Limit femtosecond laser pulses with Gaussian beam profiles. The pulse spectrum was broadened quasi- homogeneously over the beam cross-section due to the change in the lens thickness compensating for the reduction of the beam intensity from its center to periphery. In experimental demonstrations a set of chirped mirrors allowed for the spectral phase correction to a final pulse compression of 20?fs from 40?fs.     

Slow cracklike dynamics at the onset of frictional sliding

We propose a friction model which incorporates interfacial elasticity and whose steady state sliding relation is characterized by a generic nonmonotonic behavior, including both velocity weakening and strengthening branches. In 1D and upon the application of sideway loading, we demonstrate the existence of transient cracklike fronts whose velocity is independent of sound speed, which we propose to be analogous to the recently discovered slow interfacial rupture fronts. Most importantly, the properties of these transient inhomogeneously loaded fronts are determined by steady state front solutions at the minimum of the sliding friction law, implying the existence of a new velocity scale and a "forbidden gap" of rupture velocities. We highlight the role played by interfacial elasticity and supplement our analysis with 2D scaling arguments.     

Interaction of a Solitary Wave with an External Force Moving with Variable Speed

The interaction of a solitary wave with an external force moving with constant acceleration is studied within the forced Korteweg-de Vries equation. For the case of a weak isolated force an asymptotic model based on equations for the amplitude and position of the solitary wave is developed. Phase portraits for this asymptotic system are obtained analytically and numerically. Analysis has shown that an accelerated force of either sign can capture a solitary wave if the acceleration is less than a certain critical value, depending on the forcing amplitude (for the case of a constant force speed only a positive force can capture a solitary wave). Direct numerical simulation of the forced Korteweg-de Vries equation has confirmed the predictions of the asymptotic model. Also, it is shown numerically that the accelerated force can capture more than one solitary wave.     

A unified theory of ionosphere-plasmasphere transport ofsuprathermal electrons

The authors present a model of suprathermal electrons in the ionosphere and plasmasphere based on a solution to the kinetic equation along the entire length of a closed magnetic field line, that is, simultaneously for the two conjugate ionospheres and the plasmasphere. They call this the unified approach. It allows the determination of the distribution in energy and pitch-angle of photoelectrons along the complete length of the field line thereby avoiding the introduction of artificial boundaries between the ionosphere and magnetosphere and, consequently, avoids problems introduced by the uncertainty of these boundary conditions. In addition, it automatically accounts for back-scattered electrons in the atmosphere and plasmasphere, and avoids splitting photoelectrons into a loss-cone and a trapped population. The method is not limited to specific situations such as conjugated sunrise or symmetrical illumination of hemispheres, but is equally applicable to arbitrary illumination conditions