237 research outputs found

    Factors determining the fluctuation of fluoride concentrations in PM10 aerosols in the urbanized coastal area of the Baltic Sea (Gdynia, Poland)

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    Fluoride concentrations were determined in PM10 samples collected in the urbanized coastal area of the Baltic Sea (Gdynia) in the period between 1 August 2008 and 8 January 2010. F(−) concentrations remained within the range of 0.4–36.6 ng · m(−3). The economic transformations which have taken place in Poland increasing ecological awareness have had an excellent effect on the levels of fluoride pollution in the air of the studied region. In our measurements, fluoride concentrations increased in wintertime, when air temperature dropped, at low wind speeds (<1 m · s(−1)) and with low dispersion of pollutants originating from local sources (traffic, industry, domestic heating). At times when wind speed grew to >10 m · s(−1), fluorides were related to marine aerosols or else brought from distant sources. Apart from wind speed and air temperature, other significant meteorological parameters which determined the variability of F(−) turned out to be air humidity and precipitation volume. Aerosols were washed out effectively, even with small precipitation (h = 4 mm), and if a dry period lasted for several days, their concentrations grew rapidly to over 30.0 ng · m(−3)

    Dioxins : validation of food frequency questionnaire and intake in a group of adolescents

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    Introduction A lot of has been heard about dioxins and dioxins-like compounds. These molecules are typically connected in public awareness with affairs. The main source of dioxins for humans is food (90% of typical exposition); thus, assessment of dioxins intake and monitoring of levels of dioxins in food remain an important issue. Objective The aim of the presented work was checking the reproducibility of the authors’ semi-quantitative food frequency questionnaire, focusing on products that may contain dioxins and related compounds among adolescents. The uptake of these compounds was also assessed using obtained data. For survey purposes, an album of food products from the questionnaire was constructed. Material and Methods A modified semi-quantitative food frequency questionnaire was constructed and distributed twice in a 2-week time span among 55, 15-year-old, students of secondary schools. Results The correlation coefficient for both declared frequencies and assessed amounts in the case of the majority of food items was above 0.70. The average assessed intake of dioxins and related compounds was 1.57pgWHO-TEQ/kg body weight per day, and 1.85 pgWHO-TEQ/kg body weight per day, during test and retest, respectively. Conclusions The modified semi-quantitative food frequency questionnaire is a reproducible tool that can be used for adolescents. Average intake in the analyzed group was lower than the Tolerable Daily Intake, but in contrast to other countries remains one of the highest intakes in a comparable age group. The main sources of dioxins exposition were fish (38%), and meat products

    Structure and properties of slow-resorbing nanofibers obtained by (co-axial) electrospinning as tissue scaffolds in regenerative medicine

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    With the rapid advancement of regenerative medicine technologies, there is an urgent need for the development of new, cell-friendly techniques for obtaining nanofibers—the raw material for an artificial extracellular matrix production. We investigated the structure and properties of PCL10 nanofibers, PCL5/PCL10 core-shell type nanofibers, as well as PCL5/PCLAg nanofibres prepared by electrospinning. For the production of the fiber variants, a 5–10% solution of polycaprolactone (PCL) (Mw = 70,000–90,000), dissolved in a mixture of formic acid and acetic acid at a ratio of 70:30 m/m was used. In order to obtain fibers containing PCLAg 1% of silver nanoparticles was added. The electrospin was conducted using the above-described solutions at the electrostatic field. The subsequent bio-analysis shows that synthesis of core-shell nanofibers PCL5/PCL10, and the silver-doped variant nanofiber core shell PCL5/PCLAg, by using organic acids as solvents, is a robust technique. Furthermore, the incorporation of silver nanoparticles into PCL5/PCLAg makes such nanofibers toxic to model microbes without compromising its biocompatibility. Nanofibers obtained such way may then be used in regenerative medicine, for the preparation of extracellular scaffolds: (i) for controlled bone regeneration due to the long decay time of the PCL, (ii) as bioscaffolds for generation of other types of artificial tissues, (iii) and as carriers of nanocapsules for local drug delivery. Furthermore, the used solvents are significantly less toxic than the solvents for polycaprolactone currently commonly used in electrospin, like for example chloroform (CHCl3), methanol (CH3OH), dimethylformamide (C3H7NO) or tetrahydrofuran (C4H8O), hence the presented here electrospin technique may allow for the production of multilayer nanofibres more suitable for the use in medical field

    Activation of Extrinsic Coagulation Pathway in Myeloproliferative Neoplasms – Preliminary Report

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    The aim of the study was to assess the activation of extrinsic blood coagulation pathway, based on the TF and TFPI measurements in patients with MPNs. The study group consisted of 17 patients with MPNs (mean age 59 years). The control group was made of 30 healthy volunteers (mean age 52 years). In blood samples tissue factor TF, tissue factor pathway inhibitor (TFPI), thrombin-antithrombin complexes (TAT) concentration and antithrombin (AT) activity were determined. The present study showed a significantly higher level of tissue factor and decreased TFPI concentration in patients with polycythemia vera, essential thrombocythemia and primary myelofibrosis. Conclusions: 1. The results showed that in all groups of patients with MPNs an extrinsic activation of coagulation, resulting in a high concentration of TF in the blood of these patients, occurs. 2. It seems that in patients with ET, PMF and PV, an extrinsic activation of coagulation is inhibited by TFPI inhibitor as evidenced by its reduced concentration observed in the blood of these patients (the result of extrinsic consumption in the track).Celem pracy była ocena aktywności krzepnięcia krwi drogą zewnątrzpochodną u chorych na przewlekłe nowotwory mieloproliferacyjne (PZM), na podstawie oceny stężenia czynnika tkankowego (TF) i inhibitora drogi zewnątrzpochodnej układu krzepnięcia (TFPI). Badaniami objęto grupę 17 chorych na PZM (kobiet i mężczyzn w średnim wieku 59 lat). Grupę kontrolną stanowiło 30 zdrowych ochotników, kobiet i mężczyzn w średnim wieku 52,4 lat. W cytrynianowej krwi żylnej oznaczono stężenie TF, całkowitej puli TFPI, stężenie kompleksów TAT oraz aktywności AT. Stwierdzono we krwi chorych na PZM istotnie podwyższone stężenie TF, a obniżone stężenie TFPI u chorych na CzP, NS i MF. Wnioski: 1. Przeprowadzone badania wykazały, że we wszystkich grupach chorych z PZM występuje aktywacja krzepnięcia drogą zewnątrzpochodną, czego wyrazem jest wysokie stężenie TF we krwi tych chorych. 2. Wydaje się, że u chorych na NS, MF i CzP aktywacja układu krzepnięcia drogą zewnątrzpochodną jest hamowana przez inhibitor TFPI, o czym może świadczyć obniżone jego stężenie obserwowane we krwi tych chorych (wynik zużycia w torze zewnątrzpochodnym)

    Branched polyurethanes based on synthetic polyhydroxybutyrate with tunable structure and properties

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    Branched, aliphatic polyurethanes (PURs) were synthesized and compared to linear analogues. The influence of polycaprolactonetriol and synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments on structure, thermal and sorptive properties of PURs was determined. Using FTIR and Raman spectroscopies it was found that increasing the R,S-PHB amount in the structure of branched PURs reduced a tendency of urethane groups to hydrogen bonding. Melting enthalpies (on DSC thermograms) of both soft and hard segments of linear PURs were higher than branched PURs, suggesting that linear PURs were more crystalline. Oil sorption by samples of linear and branched PURs, containing only polycaprolactone chains in soft segments, was higher than in the case of samples with R,S-PHB in their structure. Branched PUR without R,S-PHB absorbed the highest amount of oil. Introducing R,S-PHB into the PUR structure increased water sorption. Thus, by operating the number of branching and the amount of poly([R,S]-3-hydroxybutyrate) in soft segments thermal and sorptive properties of aliphatic PURs could be controlled

    Sol-gel synthesis of iron oxide-silica composite microstructures

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    Spherical silica particles doped with iron oxide have been synthesized via base-catalyzed one-pot sol–gel process using tetraethoxysilane (TEOS) and iron(III) eth- oxide (ITE) as co-precursors. In the modified Sto ̈ ber pro- cess adopted, depending on the concentration of ITE in the starting composition, materials of various morphologies were observed under a scanning electron microscope and an atomic force microscope. The presence of ITE signifi- cantly affected the formation process of particulate silica; the spherical particles were formed accompanied by the co- presence of irregular-shaped finer aggregates. The fraction of the aggregates with rough surfaces increased with an increase of the ITE content in the reaction mixture. Both the spherical particles and irregular-shaped aggregates contained iron hydroxide and they exhibited paramagnetic behavior. The chemical composition and physicochemical properties of the materials were determined using various complementary spectroscopic methods

    Effect of elevated physical activity on changes in body composition and subcutaneous fat distribution in boys aged 10 to 16 years: a longitudinal study

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    AbstrAct: The study is aimed at evaluation of the effect of regular physical activity on total and subcutaneous body fat and its distribution in boys aged 10 to 16 years. A three-year longitudinal study was carried out in order to monitor physical development in 237 boys from sports schools and regular schools in Warsaw, Poland. The boys were selected so that their rate of puberty changes was similar based on evaluation of voice and facial hair. The authors measured 5 skinfolds in the following sites: triceps, calf, subscapular, suprailiac, and abdominal skinfolds. The percentage fraction of total body fat in body mass was measured by means of Tanita TBF 300 electronic body composition analyser. A limb fat to trunk fat ratio (LF/TF) was also calculated in order to evaluate the type of distribution of subcutaneous fat in boys and monitor its changes as affected by regular high physical activity throughout puberty. Lower total body fat and subcutaneous fat in boys from sports schools was the effect of considerably higher physical activity. It was demonstrated that with some minimal values of total body fat and subcutaneous fat, physical activity did not cause a reduction in body fat. It was found that elevated physical activity in boys is conducive to development of a more limb-oriented (peripheral) fatness, which is more favourable to human health
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