Soliton algebra by vortex-beam splitting

We experimentally demonstrate the possibility of breaking up intense vortex light beams into stable and controllable sets of parametric solitons. We report observations performed in seeded second-harmonic generation, but the scheme can be extended to all parametric processes. The number of generated solitons is shown to be determined by a robust arithmetic rule.     

Proton nuclear magnetic resonance characterisation of glycosaminoglycans using chemometric techniques

Various types of glycosaminoglycans (GAGs) including heparins, chondroitin sulfates, dermatan sulfate and hyaluronic acid were studied from their proton nuclear magnetic resonance (1H NMR) spectra using chemometric techniques. Despite the complexity of the 1H NMR signals, data analysis using principal component analysis enabled the different GAG classes to be distinguished and permitted their classification according to their chemical structure. The analysis of the composition of the major disaccharide unit and other relevant chemical structures in the heparin samples was performed using partial least squares regression.     

Real time electroporation control for accurate and safe in vivo non-viral gene therapy

In vivo cell electroporation is the basis of DNA electrotransfer, an efficient method for non-viral gene therapy using naked DNA. The electric pulses have two roles, to permeabilize the target cell plasma membrane and to transport the DNA towards or across the permeabilized membrane by electrophoresis. For efficient electrotransfer, reversible undamaging target cell permeabilization is mandatory. We report the possibility to monitor in vivo cell electroporation during pulse delivery, and to adjust the electric field strength on real time, within a few microseconds after the beginning of the pulse, to ensure efficacy and safety of the procedure. A control algorithm was elaborated, implemented in a prototype device and tested in luciferase gene electrotransfer to mice muscles. Controlled pulses resulted in protection of the tissue and high levels of luciferase in gene transfer experiments where uncorrected excessive applied voltages lead to intense muscle damage and consecutive loss of luciferase gene expression.     

Enhancing the axial resolution of quantum optical coherence tomography by chirped quasi-phase matching

We show theoretically that a chirped quasi-phase-matching nonlinear crystal structure can significantly enhance the axial resolution in quantum optical coherence tomography by increasing the spectral width of the generated entangled photon pairs. For pulsed pumps we show how the pump-pulse duration affects the maximum resolution attainable.     

On Blocks with Nilpotent Coefficient Extensions

For modular group algebras over an arbitrary field we define new type of blocks: blocks with nilpotent extensions, and describe their source algebras. To do it, a general pattern is proposed for relations between the source algebra of a block and the source algebra of a block appearing in its decomposition in a suitable extension of the field of coefficients.     

Change of strength of polymeric materials in the process of orientation

In the process of orientation the strength of polymeric materials changes as a result of a net increase in the number of ordered structural elements. It is shown that the model obtained can be used to predict the effect of orientation on the strength of polymers. The theoretical relations satisfactorily describe the available experimental data.Scientific-Research Institute of the Tire Industry, Moscow. Translated from Mekhanika Polimerov, No. 5, pp. 848–853, September–October, 1970.     

Breakdown of high-pressure polyethylene in bulk

The mechanism of polyethylene breakdown in bulk at low initial stresses, relaxing during the breakdown process, is discussed. Optical, electron, and scanning microscopy were used to investigate the surface of disintegrating polyethylene for cable insulation. It was found that in prolonged tests the breakdown surface has an appearance typical for the brittle breakdown of glass polymers. It was also established that in the case of brittle breakdown with clearly expressed mirror-like and rough zones, the disintegration process passess passes through an evident deformation of the surface layer and the formation of micronecks prior to rupture.Translated from Mekhanika Polimerov, No. 5, pp. 935–936, September–October, 1972.