On the Difference in Action of the Laser Light with Wavelength Near 2mm on Biotissue in Gas and Water Media

It is shown that unlike action in the air environment, section of the biotissue in the water environment (physiological solution) is performed by the steam-gas stream which is formed as a result of superintensive boiling in thin (about 0.1 mm) a liquid layer in which absorbed laser radiation. Coagulation of the biotissue, adjacent to a section, happens due to heat which is produced via vapor condensation. Keywords: laser radiation in urology, a laser enucleation of the BPH, laser removal of the bladder cancer

Features of Polymeric Structures By Surface—Selective Laser Sintering of Polymer Particles Using Water as Sensitizer

The development of scaffolds with strictly specific properties is a key aspect of functional tissue regeneration, and it still remains one of the greatest challenges for tissue engineering. This study is aimed to determine the possibility of producing three-dimensional polylactide (PLA) scaffolds using the method of surface-selectiv  laser sintering (SSLS) for bone tissue regeneration. In this work, the authors also improved PLA scaffold adhesion properties, which are crucial for successful cellular growth and expansion. Thus, SSLS method proved to be effective in designing threedimensional porous scaffolds with differentiated mechanical properties. Keywords: regenerative medicine, scaffolds, polylactide, surface – selective laser . sintering, tissue engeneering

Flame front propagation IV: Random Noise and Pole-Dynamics in Unstable Front Propagation II

The current paper is a corrected version of our previous paper arXiv:adap-org/9608001. Similarly to previous version we investigate the problem of flame propagation. This problem is studied as an example of unstable fronts that wrinkle on many scales. The analytic tool of pole expansion in the complex plane is employed to address the interaction of the unstable growth process with random initial conditions and perturbations. We argue that the effect of random noise is immense and that it can never be neglected in sufficiently large systems. We present simulations that lead to scaling laws for the velocity and acceleration of the front as a function of the system size and the level of noise, and analytic arguments that explain these results in terms of the noisy pole dynamics.This version corrects some very critical errors made in arXiv:adap-org/9608001 and makes more detailed description of excess number of poles in system, number of poles that appear in the system in unit of time, life time of pole. It allows us to understand more correctly dependence of the system parameters on noise than in arXiv:adap-org/9608001Comment: 23 pages, 4 figures,revised, version accepted for publication in journal "Combustion, Explosion and Shock Waves". arXiv admin note: substantial text overlap with arXiv:nlin/0302021, arXiv:adap-org/9608001, arXiv:nlin/030201

Temperature effects in low-frequency Raman spectra of corticosteroid hormones

Experimental Raman spectra of the corticosteroid hormones corticosterone and desoxycorticosterone are recorded at different temperatures (in the range of 30–310 K) in the region of low-frequency (15–120 cm−1) vibrations using a solid-state laser at 532.1 nm. The intramolecular vibrations of both hormones are interpreted on the basis of Raman spectra calculated by the B3LYP/6-31G(d) density functional theory method. The intermolecular bonds in tetramers of hormones are studied with the help of the topological theory of Bader using data of X-ray structural analysis for crystalline samples of hormones. The total energy of intermolecular interactions in the tetramer of desoxycorticosterone (−49.1 kJ/mol) is higher than in the tetramer of corticosterone (−36.9 kJ/mol). A strong intramolecular hydrogen bond O21-H⋯O=C20 with an energy of −42.4 kJ/mol was revealed in the corticosterone molecule, which is absent in the desoxycorticosterone molecule. This fact makes the Raman spectra of both hormones somewhat different. It is shown that the low-frequency lines in the Raman spectra are associated with skeletal vibrations of molecules and bending vibrations of the substituent at the C17 atom. The calculated Raman spectrum of the desoxycorticosterone dimer allows one to explain the splitting and shift of some lines and to interpret new strong lines observed in the spectra at low temperatures, which are caused by the intermolecular interaction and mixing of normal vibrations in a crystal cell. On the whole the calculated frequencies are in a good agreement with the experimental results

Extended Emission from Short Gamma-Ray Bursts Detected with SPI-ACS/INTEGRAL

The short duration (T90 < 2 s) gamma-ray bursts (GRBs) detected in the SPI-ACS experiment onboard the INTEGRAL observatory are investigated. Averaged light curves have been constructed for various groups of events, including short GRBs and unidentified short events. Extended emission has been found in the averaged light curves of both short GRBs and unidentified short events. It is shown that the fraction of the short GRBs in the total number of SPI-ACS GRBs can range from 30 to 45%, which is considerably larger than has been thought previously.Comment: 27 pages, 10 figure