Continuous VOC flux measurements on boreal forest floor

Background and Aims

Volatile organic compound (VOC) emissions from biogenic sources are important contributors to chemical reactions in the air. Soil/forest floor VOCs contribute significantly to the ecosystem scale emissions, however, these emissions and their temporal and spatial variations are poorly characterised. The below-canopy VOC emissions have been measured mainly in campaigns; continuous measurements over the whole growing season are rare.

Methods

VOCs were measured from boreal forest floor over the snow-free season 2010 in southern Finland with automated flow-through chambers connected to proton transfer reaction-mass spectrometer (PTR-MS). We measured 10 masses in total, of which five quantitatively (M33, M45, M59, M69, M137).

Results

All of the fluxes showed clear diurnal and seasonal variation, being at their highest in early summer. Spatial variation in the fluxes was great and the lowest rates were found in chambers with dense vegetation cover. Also, VOCs deposition was observed regularly. Monoterpene (M137) emissions were one magnitude higher (up to 264 ng?m^?2?s^?1) than other emissions. The VOC fluxes correlated positively with temperature and light, while relative humidity correlated negatively.

Conclusions

Results indicated that forest floor plays a substantial role in the boreal forest total VOC emissions. Understanding the processes controlling VOC emissions requires more detailed analysis and long-time measurements with sufficient time resolution and analytical accuracy.     

Detection and quantitation of colored deposit-forming <Emphasis Type="Italic">Meiothermus</Emphasis> spp. in paper industry processes and end products

Colored biofilms cause problems in paper industry. In this work we used real-time PCR to detect and to quantitate members of the genus Meiothermus from the process samples and end products from 24 machines manufacturing pulp, paper and board in four countries. The results obtained from 200 samples showed the importance of members of the genus Meiothermus as ubiquitous biofoulers in paper machines. This genus was the dominant biofouler in some mills. From ≤10⁴ to 10¹¹ copies of Meiothermus 16S rRNA genes were found per gram of process deposit (wet weight). Meiothermus spp. were found in paper and board products with colored defects and connection between deposit-forming microbes and end-product spots was shown. 16S rRNA gene sequences of 29 biofilm producing bacterial isolates from different mills were determined. Based on sequence data, 25 of the isolates were assigned to the genus Meiothermus, with Meiothermus silvanus and M. ruber as the most frequent species.     

Immeasurable levels of serum phosphate--an unidentified cause of respiratory failure in a diabetic patient

We report a case of immeasurable levels of serum phosphate in a patient with juvenile type Diabetes mellitus and diabetic ketoacidosis who developed respiratory failure. A 27-year-old female with juvenile type insulin-dependent Diabetes mellitus was admitted because of suspected acute mediastinitis and respiratory failure, probably, among other responsible factors, caused and complicated by undetectable levels of serum phosphate. The serum phosphate concentration three days after aggressive treatment was only 0.2 mmol/L. Furthermore, a significant improvement in weakness and lethargy was observed. To the best of our knowledge, this is the first described case of immeasurable levels of serum phosphate. In patients with Diabetes mellitus, serum phosphate concentrations should be routinely checked in order to avoid additional complications.     

Body mass index, waist circumference and waist-to-hip ratio: which anthropometric indicator is better predictor for the hypertension development in women population of the island Cres

The aim of this research was to investigate the prevalence of obesity and high blood pressure and to prove which of three anthropometric indicators of obesity - waist circumference, body mass index (BMI) waist-to-hip ratio - is better predictor for the development of hypertension in women population of the island of Cres. We approached separately groups of women with measured high blood pressure and with previously diagnosed. The research was preformed within the research project "Genetic and biomedical characteristics of the population of the island of Cres". This was the cross sectional study and data were obtained on the sample of 247 females over 18 years old that voluntarily participated in this study. In our study group the prevalence of overweight was 39.0%, obesity 27.5%, increased waist circumference was present in 69.4% while increased blood pressure was found in 53.0% examinees. Our results indicate that age, BMI, impaired glucose concentration and serum cholesterol could be considered as predictors for the development of arterial hypertension, whether measured or previously diagnosed.     

Mechanisms of biofilm formation in paper machine by Bacillus species: the role of Deinococcus geothermalis

Mechanisms for the undesired persistence of Bacillus species in paper machine slimes were investigated. Biofilm formation was measured for industrial Bacillus isolates under paper machine wet-end-simulating conditions (white water, pH 7, agitated at 45°C for 1–2 days). None of the 40 tested strains of seven Bacillus species formed biofilm on polished stainless steel or on polystyrene surfaces as a monoculture. Under the same conditions, Deinococcus geothermalis E50051 covered all test surfaces as a patchy thick biofilm. The paper machine bacilli, however, formed mixed biofilms with D. geothermalis E50051 as revealed by confocal microscopy. Biofilm interactions between the bacilli and the deinococci varied from synergism to antagonism. Synergism in biofilm formation of D. geothermalis E50051 was strongest with Bacillus coagulans D50192, and with the type strains of B. coagulans, B. amyloliquefaciens or B. pumilus. Two B. licheniformis, one B. amyloliquefaciens, one B. pumilus and four B. cereus strains antagonized biofilm production by D. geothermalis. B. licheniformis D50141 and the type strain of B. licheniformis were the strongest antagonists. These bacteria inhibited deinococcal growth by emitting heat-stable, methanol-soluble metabolite(s). We conclude that the persistence of Bacillus species in paper machine slimes relates to their ability to conquer biofilms formed by primary colonizers, such as D. geothermalis. Journal of Industrial Microbiology & Biotechnology (2001) 27, 343–351. Received 17 April 2001/ Accepted in revised form 16 July 2001     

Risk behaviors for getting HIV infection among the Croatian men who have sex with men in 2007

This survey was conducted with the aim of obtaining the information on the sexual risk behavior of Croatian men who have sex with men (MSM) two years after the first research. There was total of 820 respondents recruited at seven frequent meeting places of Croatian MSM in Zagreb and Rijeka, as well as one gay-oriented web-site. The overall response rate was 17.6% which is 1.4 percentage point less than it was two years ago. The rate of condom use during last anal intercourse was 53.2% and 69% of those who used a lubricant had chosen a correct water-based product which is increase of 15% comparing to the last research. Only 27% of those who had also had sex with women (MSM/MSW) during last 12 months regularly used protection. The results of this research suggest that there are trends in declining of some risk behaviors among Croatian MSM but there is a lot of space for focused and effective prevention activities on increasing the risk perception and reducing risk behaviors.     

Bursts of CO2 released during freezing offer a new perspective on avoidance of winter embolism in trees

MethodsCO₂ efflux measurements were conducted during freezing experiments for saplings of three Scots pine (Pinus sylvestris) and three Norway spruce (Picea abies) trees under laboratory conditions, and the magnitudes of the freezing-related bursts of CO₂ released from the stems were analysed using a previously published mechanistic model of CO₂ production, storage, diffusion and efflux from a tree stem. The freezing-related bursts of CO₂ released from a mature Scots pine tree growing in field conditions were also measured and analysed.ConclusionsAll gases dissolved in the xylem sap are not trapped within the ice in the stem during freezing, as has previously been assumed, thus adding a new dimension to the understanding of winter embolism formation. The conduit water volume not only determines the volume of bubbles formed during freezing, but also the efficiency of gas efflux out of the conduit during the freezing process.     

Effect of Sodium Nitrite and Sodium Nitrate on Botulinal Toxin Production and Nitrosamine Formation in Wieners

Wieners were formulated and processed approximating commercial conditions as closely as possible. Twenty-four batches of product were made with the addition of six levels of sodium nitrite (0, 50, 100, 150, 200, and 300 mug/g), four levels of sodium nitrate (0, 50, 150, and 450 mug/g), and two levels of Clostridium botulinum (0 and 620 spores/g). After formulation, processing, and vacuum packaging, portions of each batch were incubated at 27 C or held for 21 days at 7 C followed by incubation at 27 C for 56 days. The latter storage condition approximated distribution of product through commercial channels and potential temperature abuse at the consumer level. Samples were analyzed for botulinal toxin, nitrite, and nitrate levels after 3, 7, 14, 21, 28, and 56 days of incubation. When nitrite was not added, toxic samples were detected after 14 days of incubation at 27 C. At the lowest level of nitrite added (50 mug/g), no toxic samples were observed until 56 days of incubation. Higher levels of nitrite completely inhibited toxin production throughout the incubation period. Nine uninoculated samples, representing various levels and combinations of nitrite and nitrate, were evaluated organoleptically. The flavor quality of wieners made with nitrite was judged significantly higher (P = 0.05) than of wieners made without nitrite. The nine samples were negative for 14 volatile nitrosamines at a sensitivity level of 10 ng/g. The results indicated that nitrite effectively inhibited botulinal toxin formation at commercially employed levels in wieners and that detectable quantities of nitrosamines were not produced during preparation and processing of the product for consumption.