New microorganism isolation techniques with emphasis on laser printing.

The study of biodiversity, growth, development, and metabolism of cultivated microorganisms is an integral part of modern microbiological, biotechnological, and medical research. Such studies require the development of new methods of isolation, cultivation, manipulation, and study of individual bacterial cells and their consortia. To this end, in recent years, there has been an active development of different isolation and three-dimensional cell positioning methods. In this review, the optical tweezers, surface heterogeneous functionalization, multiphoton lithography, microfluidic techniques, and laser printing are reviewed. Laser printing is considered as one of the most promising techniques and is discussed in detail.

Oscillator strengths of UV absorption and luminescence for oxygen-deficient centers in germanosilicate fibers.

The time-resolved measurements of triplet and singlet luminescence from germanium oxygen-deficient centers (GODC's) in germanosilicate fibers excited by short UV laser pulses are used to determine the cross section of UV absorption of GODC's at lambda = 248 nm (sigma = 5 x 10(-18) cm(2)), the oscillator strength of UV absorption (f(abs) = 0.027), and UV luminescence (f(lum) = 0.031). The basis for these measurements is the direct luminescence detection of lifetimes of electronically excited states of GODC's, the saturation of triplet luminescence signals, and the analysis of the rate equations that govern the laser photoexcitation and relaxation processes in GODC's.