Time domain diffuse Raman spectrometer based on a TCSPC camera for the depth analysis of diffusive media.

We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212 ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106 ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.

Carcinogens in rubber production in the Soviet Union.

In a preliminary phase of a broad research project on cancer among workers in a rubber footwear plant in Moscow, exposure to several known or potential carcinogens was assessed. There were high dust contents bearing both toxic substances and carcinogens. The highest concentrations of benzo[a]pyrene (500-14,400 micrograms) were found on the soot used as a filler, and the maximum N-dimethylnitrosamine (DMNA) level was measured in thiram (150-23,868 micrograms.kg-1). Air samples from the vulcanization process and the pressing of rubber goods showed BaP levels of up to 1.43 micrograms.m-3. In the work area where polyvinyl chloride was used, the mean vinyl chloride concentration was 0.21 (SE 0.06) mg.m-3. The mean value of the acrylonitrile concentrations in the workroom area was 0.19 (SE 0.07) mg.m-3. Very high levels of DMNA and N-diethylnitrosamine were measured in the preparatory shop in the winter.

[Carcinogenic and nonspecific harmful factors in the rubber industry]. / Kantserogennye i nespetsificheskie povrezhdaiushchie faktory v proizvodstve reziny.

The hygienic analysis of working conditions at a rubber production plant revealed that measures aimed at the decrease of dust load of the preparatory process were not sufficient. High dust load was accompanied by unfavourable microclimatic conditions. The content of carcinogens, such as benz(a)--pyrene, acrylonitrile, and vinyl chloride on the average did not exceed MACs. Their highest concentrations exceeding MACs were detected in vulcanization and compaction bays. Preventive measures should be directed at reducing workers' exposure to carcinogens and nonspecific occupational damaging factors by means of automatization and hermetic sealing of the equipment along with the introduction of robotized systems.