45 research outputs found
Footprint Areas of Pollen From Alder (Alnus) and Birch (Betula) in the UK (Worcester) and Poland (Wrocław) During 2005–2014
In this study we analyzed daily pollen concentrations of Alnus spp. and Betula spp. from Worcester, UK and Wrocław,
Poland. We analyzed seasonality, annual pollen index and footprint areas for the observed pollen concentrations by using the trajectory model hybrid single particle Lagrangian integrated trajectory (HYSPLIT). We examined 10 years of data during the period 2005–2014 and found substantial differences in the seasonality, pollen indices and footprint areas. For both genera, concentrations in Wrocław are in general much higher, the seasons are shorter and therefore more intense than in Worcester. The reasons appear to be related to the differences in overall climate between the two sites and more abundant sources in Poland than in England. The footprint areas suggest that the source of the pollen grains are mainly local trees but appear to be augmented by remote sources, in particular for Betula spp. but only to a small degree for Alnus spp. For Betula spp., both sites appear to get contributions from areas in Germany, the Netherlands and Belgium, while known Betula
spp. rich regions in Russia, Belarus and Scandinavia had a very limited impact on the pollen concentrations in Worcester and Wrocław. Substantial and systematic variations in pollen indices are seen for Betula spp. in Wrocław with high values every second year while a similar pattern is not observed for Worcester. This pattern was not reproduced for Alnus spp
Extension of WRF-Chem for birch pollen modelling – a case study for Poland.
In recent years, allergies due to airborne pollen have shown an increasing trend, along with the severity of allergic symptoms in most industrialised countries, while synergism with other common atmospheric pollutants has also been identified as affecting the overall quality of citizenly’ life. In this study we propose the state-of-the-art WRF-Chem model, which is a complex Eulerian meteorological model integrated on-line with atmospheric chemistry. We used a combination of the WRF-Chem extended towards birch pollen, and the emission module based on heating degree days, which has not been tested before. The simulations were run for the moderate season in terms of birch pollen concentrations (year 2015) and high season (year 2016) over Central Europe, which were validated against 11 observational stations located in Poland. The results show that there is a big difference in the model’s performance for the two modelled years. In general, the model overestimates birch pollen concentrations for the moderate season and highly underestimates birch pollen concentrations for the year 2016. The model was able to predict birch pollen concentrations for first allergy symptoms (above 20 pollen m-3) as well as for severe symptoms (above 90 pollen m-3) with Probability of Detection at 0.78 and 0.68 and Success Ratio at 0.75 and 0.57, respectively for the year 2015. However, the model failed to reproduce these parameters for the year 2016. The results indicate the potential role of correcting the total seasonal pollen emission in improving the model’s performance, especially for specific years in terms of pollen productivity.
The application of chemical transport models such as WRF-Chem for pollen modelling provides a great opportunity for simultaneous simulations of chemical air pollution and allergic pollen with one goal, which is a step forward for studying and understanding the co-exposure of these particles in the air
Enhanced ERbeta immunoexpression and apoptosis in the germ cells of cimetidine-treated rats
<p>Abstract</p> <p>Background</p> <p>Cimetidine, refereed as antiandrogenic drug, causes hormonal changes in male patients such as increased testosterone and FSH levels. In the rat testis, structural alterations in the seminiferous tubules have been related to germ cell loss and Sertoli cell death by apoptosis. Regarding the important role of Sertoli cells in the conversion of testosterone into estrogen, via aromatase, the immunoexpression of estrogen receptors-beta (ERbeta) was evaluated in the germ cells of untreated and treated rats with cimetidine. A relationship between ERbeta immunoreactivity and apoptosis was also investigated in the germ cells of damaged tubules.</p> <p>Methods</p> <p>Immunohistochemistry for detection of ERbeta and TUNEL method were performed in testicular sections of adult male rats treated with 50 mg/Kg of cimetidine (CmG) or saline solution (CG) for 52 days.</p> <p>Results</p> <p>In CG, a cytoplasmic immunoexpression for ERbeta was observed in spermatogonia, primary spermatocytes and spermatids. An evident ERbeta immunoreactivity was always observed in the flagellum and residual bodies of late spermatids. In CmG, the cytoplasm or cytoplasm and nuclei of germ cells of the damaged tubules by cimetidine showed enhanced ERbeta immunostaining. TUNEL-labeling was usually observed in the same germ cell types exhibiting enhanced ERbeta immunoreactivity.</p> <p>Conclusion</p> <p>The presence of ERbeta immunolabeling in the flagellum and residual bodies of spermatids reinforces the role of estrogen in spermiogenesis. The overexpression of ERbeta in the germ cells of CmG could be related to a possible interference of cimetidine on tubular androgenization and/or on the intratubular aromatase due to Sertoli cell damage. The parallelism between ERbeta overexpression and apoptosis indicates a participation of ERbeta on germ cell death.</p
Oxidative stress in pregnancy and fertility pathologies
Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders
Modelowanie kinetyki procesu ozonowania Reactive Black 5
C.I. Reactive Black 5 (RB5) is the most commonly used dye in the textile industry. Ozone is a strong oxidan that can decompose many barely degradable pollutants, including dyes. Although there are many literature reports devoted to the treatment of textile wastewater and dye solutions by ozone, the ozonation mechanism and modeling of the kinetics is still not well covered. In this work a kinetic model of the process of RB5 decolourisation by ozone has been proposed and validated on the basis of experimental data. The experiments were carried out in a liquid-liquid system to avoid mass transfer limitation. A model was established for acid reaction medium. The main RB5 reaction was direct oxidation of the dye with molecular ozone. The self-decomposition of ozone in liquid phase was taken into account and described by an empirical equation. The reaction rate constants of RB5 with ozone were estimated from the experimental data in the range of (1.88 ± 0.08) × 104 – (2.53 ± 0.10) × 105 M-1s-1 (invariant with initial dye concentration). An empirical equation k′ 2 = 1.06 × 108(COH−)0.31 was built for the constant to make it dependent on the pH value. A solution of the non-linear inverse problem allowed for identification of the kinetic constants on the basis of the experimental data obtained. The model gave a good match between the prediction and experimental data for pH between 1.88 and 4.0.Reactive Black 5 (RB5) jest powszechnie stosowanym barwnikiem w przemyśle włókienniczym. Ozon, będący silnym utleniaczem, jest w stanie rozłożyć wiele trudno degradowalnych substancji w tym barwniki. Pomimo, iż oczyszczanie ścieków włókienniczych i roztworów barwników ozonem było tematem wielu pozycji literaturowych, niewiele pośród nich dotyczyło badań nad poznaniem mechanizmu utleniania oraz modelowania kinetyki tego procesu. W niniejszej pracy zaproponowano matematyczny model opisujący kinetykę procesu odbarwiania barwnika RB5 za pomocą ozonu. Walidacji dokonano poprzez porównanie wyników modelowania do danych eksperymentalnych. Eksperymenty prowadzono w układzie homogenicznym ciecz-ciecz, aby uniknąć limitacji transferu masy między fazami układu. Model został opracowany dla procesu przebiegającego w środowisku kwaśnym, gdzie główną reakcją było bezpośrednie utlenianie barwnika cząsteczkowym ozonem z jednoczesnym uwzględnieniem rozkładu ozonu w fazie ciekłej. Model opisano równaniem empirycznym. Wartości stałych szybkości reakcji RB5 z ozonem oszacowane na podstawie danych eksperymentalnych znajdowały się w zakresie od do M-1s-1 i były niezależne od początkowego stężenia substratu. W celu uzależnienia stałych szybkości od wartości pH, wyznaczono zależność empiryczną w postaci. Rozwiązanie nieliniowego problemu odwrotnego pozwoliło na identyfikację stałych kinetycznych na podstawie danych eksperymentalnych. Otrzymano dobrą zgodność pomiędzy wynikami modelowania a danymi doświadczalnymi dla wartości pH w zakresie 1,88-4,0