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Pożytek z badań żywic kopalnych świata metodą spektroskopii w podczerwieni (IR)

Kosmowska-Ceranowicz B.

Przegląd Geologiczny

2017

Vol. 65, nr 8

505--510

Infrared absorption spectroscopy was introduced at the Museum of the Earth of the Polish Academy of Sciences in Warsaw in 1985for research on fossil and subfossil resins of the world. As new reports on previously unknown findings have been made, a collection of resins from across the world has been developed according to the identifications based on the preliminary IRS method, documented by a catalogue of about 1200IR spectra, of which 344 are presented in the published ATLAS. The results of research, conducted with the participation of various teams, are presented. These include very useful activities that organize the terminology to protect against counterfeiting, and indications of the areas of differentiation of highly resin-producing forest communities, both in time and with regard to their migration over considerable distances. In search for the source tree of succinite, Pseu- dolarix vehri has been indicated based on both the IR spectra from Axel Heiberg (Canada) and the Paleogene paleogeography. In the studies of Indonesian glessites, the hypothesis of the contribution of volcanic processes to increased production of resin by trees has been proved. In amber (= succinite) with a solidfoam structure, SEM investigations revealed the presence of succinellite microcrystals (= succinic acid), hitherto known only as one of the components of dry distillation of the Baltic amber.

Time-resolved reflectometry and spectroscopy for assessment of brain perfusion and oxygenation

Liebert A., Kacprzak M., Maniewski R.

Biocybernetics and Biomedical Engineering

2007

Vol. 27, no. 1-2

217-225

Time-resolved optical methods and instrumentation for non-invasive assessment of the cerebral cortex perfusion and oxygenation are presented. The oxygenation can be calculated using the moments of the distributions of times of flight of photons measured at two wavelengths in the near infrared region. For assessment of the brain perfusion, the kinetics of the inflow and washout of an exogenous dye injected intravenously is analyzed. The instrument developed at the Institute of Biocybernetics and Biomedical Engineering PAS is equipped with picosecond diode lasers, fast photodetectors and time correlated single photon counting electronics for acquisition of the distributions of times of flight of photons. This technique allows for a depth-resolved estimation of the changes of absorption and, in consequence, for an assessment of the changes occurring in the cerebral cortex. Combination of the data from multiple sources and detectors placed on the surface of the head with the depth-resolved analysis based on the moments enables to obtain images of the cortex perfusion and/or oxygenation. Potential applications of the instrument and its limitations are also discussed.