Beryllium-7 and (210)Pb atmospheric deposition measured in moss and dependence on cumulative precipitation.

This paper focuses on analysis of the time series of (7)Be and (210)Pb activity measured in moss, and the amount, as well as duration of precipitation, to gain a better understanding of the possible relationships between airborne radionuclide deposition and precipitation. Here we consider whether the amount of these airborne radionuclides in moss samples is a cumulative measure of radionuclide deposition and decay, and a new approach for analyses of the relationships between precipitation and moss activity concentrations is suggested. Through these analyses it was shown that comparison of cumulative activity measured at one location using moss, normalized by values of cumulative amount or duration of precipitation, showed different regimes of airborne radionuclide deposition.

Correlation of unsupported ²¹°Pb activity in soil and moss.

The activities of unsupported (210)Pb, a naturally occurring radionuclide, were measured in samples of soil and terrestrial mosses collected in Serbia. Considering that clay particles in soil have a high affinity for Pb adsorption, and that mosses usually capture aerosol particles to obtain necessary nutrients, measurable amounts of airborne (210)Pb, the daughter of (222)Rn, can be registered in both soil and mosses. The objective of the present study was to determine if it is possible to compare the activity of unsupported (210)Pb in soil and moss collected at the same sampling site, and to establish if a correlation exists between these measured values.

Airborne radionuclides in mosses collected at different latitudes.

Terrestrial mosses are a promising medium for investigation and monitoring of airborne radionuclide depositions due to their widespread occurrence, ease of sampling, and the possibility of high-resolution gamma spectrometry measurements without preparatory chemical treatment of samples. The overall objective of the present study was to compare (7)Be, (210)Pb and (137)Cs activity concentrations (in Bq/kg) in moss samples collected at two different climate zones: the south of Thailand (7 °N) and in Serbia (∼45 °N) in order to examine deposition of airborne radionuclide in these distant areas. Significant difference of the (210)Pb content (almost a factor of 2) in mosses was observed. The mean value of (7)Be activity in samples from Serbia was almost 40% higher than activity of those collected in Thailand. Level of (137)Cs in Thailand mosses was below the detection limit. It was shown that air transport of water droplets in the area of waterfalls and strong turbulence can deposit U and Th daughter nuclei.

Country-specific correlations across Europe between modelled atmospheric cadmium and lead deposition and concentrations in mosses.

Previous analyses at the European scale have shown that cadmium and lead concentrations in mosses are primarily determined by the total deposition of these metals. Further analyses in the current study show that Spearman rank correlations between the concentration in mosses and the deposition modelled by the European Monitoring and Evaluation Programme (EMEP) are country and metal-specific. Significant positive correlations were found for about two thirds or more of the participating countries in 1990, 1995, 2000 and 2005 (except for Cd in 1990). Correlations were often not significant and sometimes negative in countries where mosses were only sampled in a relatively small number of EMEP grids. Correlations frequently improved when only data for EMEP grids with at least three moss sampling sites per grid were included. It was concluded that spatial patterns and temporal trends agree reasonably well between lead and cadmium concentrations in mosses and modelled atmospheric deposition.

Temporal variations of 7Be, 210Pb and 137Cs in moss samples over 14 month period.

Concentrations of (210)Pb, (7)Be and (137)Cs in moss samples were continuously measured, using low-background HPGe spectrometer at Novi Sad, Serbia (45 degrees 14'45''N, 19 degrees 51'35''E). Weekly data collected over 14 month period from January 2007 to March 2008 are presented and discussed. Measured values of (7)Be activity concentrations in dry moss samples are ranged from 201 to 920 Bq/kg showing prominent increase in summer and autumn season. Data for (210)Pb, ranged from 347 to 885 Bq/kg do not show such trend. The average concentration of (137)Cs is 8.9 Bq/kg. It is shown that yield of (7)Be can be estimated using average values of activity concentrations. Precipitation amount and duration of precipitation are measured and their possible influence on activity concentrations measured in moss samples was considered.

Possible use of terrestrial mosses in detection of atmospheric deposition of 7Be over large areas.

The activities of naturally occurring radionuclides (7)Be, (214)Bi and (210)Pb were measured in samples of terrestrial mosses collected in Serbia (42 degrees 26'19''N-45 degrees 23'12''N). The objective of this work was to establish if detectable amounts of (7)Be and (210)Pb can be found in mosses and investigate their possible variabilities over some area. These are the first steps in introducing mosses as a medium in possible monitoring of spatial distribution of (7)Be atmospheric deposition. The mean value of 360 Bq/kg of (7)Be activity was found in collected moss samples and some nonuniformity in spatial distribution (a 2.8-fold range in measured values) was observed.

Engineering of stable recombinant bacteria for production of chiral medium-chain-length poly-3-hydroxyalkanoates.

In order to scale up medium-chain-length polyhydroxyalkanoate (mcl-PHA) production in recombinant microorganisms, we generated and investigated different recombinant bacteria containing a stable regulated expression system for phaC1, which encodes one of the mcl-PHA polymerases of Pseudomonas oleovorans. We used the mini-Tn5 system as a tool to construct Escherichia coli 193MC1 and P. oleovorans POMC1, which had stable antibiotic resistance and PHA production phenotypes when they were cultured in a bioreactor in the absence of antibiotic selection. The molecular weight and the polydispersity index of the polymer varied, depending on the inducer level. E. coli 193MC1 produced considerably shorter polyesters than P. oleovorans produced; the weight average molecular weight ranged from 67,000 to 70,000, and the polydispersity index was 2.7. Lower amounts of inducer added to the media shifted the molecular weight to a higher value and resulted in a broader molecular mass distribution. In addition, we found that E. coli 193MC1 incorporated exclusively the R configuration of the 3-hydroxyoctanoate monomer into the polymer, which corroborated the enantioselectivity of the PhaC1 polymerase enzyme.

[Regulation of intraocular pressure using argon laser trabeculoplasty in various forms of open-angle glaucoma]. / Mogucnosti regulacije intraokularnog pritiska argon laser trabekuloplastikom raznih oblika glaukoma otvorenog ugla.

Argon laser trabeculoplasty was applied in 43 patients, 46 eyes. 34 eyes had had primary open-angle glaucoma, while 12 eyes had secondary open-angle glaucoma where no compensation of intraocular pressure was achieved although maximal medical therapy was conducted. Applying argon laser trabeculoplasty the intraocular pressure was normalized in 86% of eyes with a primary glaucoma considering period of 18.31 +/- 2.80 months. In 58.4% of eyes with secondary glaucoma satisfactory reduction of intraocular pressure was achieved considering period of 14.57 +/- 7.91 month.

[Dry eye as a therapeutic problem]. / Suvo oko kao terapijski problem.

Effects of substitution therapy was investigated in 42 patients having the dry eye syndrome associated with systemic diseases of connective tissues (systemic lupus, Sjögren's syndrome, etc). Artificial tears were applied: Liquifilm sol, Hydroxypropyl methylcellulose 0.3% (HPMC) and Ocutal sol. After the one-month application of each preparation, mean values of Schirmer's test were approximately identical and the differences were not statistically significant (4.5 +/- 3.5; 4.95 +/- 4.4; 4.01 +/- 3.6), differing slightly from mean values of Schirmer's test prior to the treatment (4.4 +/- 3.4; 3.9 +/- 2.5). The lacrimal secretion did not increase after the administration of the above therapy. The therapy with artificial tears resulted in the improvement of subjective complaints (scratching, dryness and burning sensation) in 65% of cases treated with Liquifilm sol, in 69% upon the administration of HMPC 0.3% and in 60% after the application of Ocutal sol.