50 research outputs found

    The future of Viscum album L. in Europe will be shaped by temperature and host availability.

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    Viscum album L. is a plant of great importance due to its influence on the host trees and, by extension, entire ecosystems. The species is also significant to humans-on the one hand, because of its use in medicine, and on the other, because of the growing threat it poses to the stability of conifer stands. Therefore, it is important to recognize the future range of three mistletoe subspecies (Viscum album subsp. album, V. album subsp. austriacum, and V. album subsp. abietis). Modelling of the potential range of these subspecies was performed using MAXENT software. Locations were collected from literature and databases. A total number of 3335 stands were used. Bioclimatic data for the current conditions and three future scenarios (SSP 1.26, SSP 3.70, SSP 5.85) were downloaded from the CHELSA database. The results confirmed that the temperature is the key variable on the potential range of the analysed subspecies. V. album subsp. abietis is withdrawing from its range according to all scenarios. In the case of V. album subsp. austriacum, a slight range shift is visible. Only the V. album subsp. album will expand non-directionally. The reason is most likely a very large number of host species and greater genetic variability compared to the subspecies found on conifers

    Electrical switching of a chiral lasing from polariton condensate in a Rashba-Dresselhaus regime

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    Efficient optical classical and quantum information processing imposes on light novel requirements: chirality with low threshold non-linearities. In this work we demonstrate a chiral lasing from an optical modes due to emerging photonic Rashba-Dresselhaus spin-orbit coupling (SOC). For this purpose we developed a new electrically tunable device based on an optical cavity filled with birefringent liquid crystal (LC) and perovskite crystals. Our novel method for the growth of single crystals of CsPbBr3_3 inorganic perovskite in polymer templates allows us to reach a strong light-matter coupling regime between perovskite excitons and cavity modes, and induce polariton condensation. The sensitivity of the LC to external electric fields lets us to tune the condensate energy in situ and induce synthetic SOC. This shapes the condensate between a single linearly polarized or two circularly polarized separated in momentum, emitting coherent light. The difference in the condensation thresholds between the two SOC regimes can be used to switch on and off the chiral condensate emission with a voltage.Comment: 8 pages, 5 figure

    Glutathione-Related Antioxidant Defense System in Elderly Patients Treated for Hypertension

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    The purpose of this study was to analyze glutathione antioxidant defense system in elderly patients treated for hypertension. Studies were carried out in the blood collected from 18 hypertensive and 15 age- and sex-matched controls, all subjects age over 60. Hypertensives were on their usual antihypertensive treatment at the time of blood collection. The concentration of glutathione (GSH) in whole blood and activities of glutathione peroxidase (GPx-1), glutathione transferase (GST), and glutathione reductase (GR) in erythrocytes were measured. The data from patients and controls were compared using independent-samples t test. P value of 0.05 and less was considered statistically significant. We observed increased glutathione-related antioxidant defense in treated hypertensive elderly patients (HT) when compared with healthy controls (C). Mean GSH concentration was significantly higher in HT when compared with C: 3.1 ± 0.29 and 2.6 ± 0.25 mmol/L, respectively, P < 0.001. Mean activity of GR was significantly higher in HT group if compared with C: 83.4 ± 15.25 U/g Hb versus 64.2 ± 8.26 U/g Hb, respectively, P < 0.001. Mean activity of GST was significantly higher in HT group compared with C: 3.0 ± 0.60 mmol CDNB-GSH/mgHb/min and 2.6 ± 0.36 mmol CDNB-GSH/mgHb/min, respectively, P < 0.05. No difference in GPx activity was observed between two groups. These results show that glutathione-related antioxidant defense system was enhanced in elderly hypertensive patients treated for their conditions. This suggests important role of glutathione system in blood pressure regulation. Alterations in concentration and activity of antioxidants observed during antihypertensive medication are likely to be related to the effect of the treatment on NO bioavailability

    No systematic effects of sampling direction on climate-growth relationships in a large-scale, multi-species tree-ring data set

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    Ring-width series are important for diverse fields of research such as the study of past climate, forest ecology, forest genetics, and the determination of origin (dendro-provenancing) or dating of archaeological objects. Recent research suggests diverging climate-growth relationships in tree-rings due to the cardinal direction of extracting the tree cores (i.e. direction-specific effect). This presents an understudied source of bias that potentially affects many data sets in tree-ring research. In this study, we investigated possible direction-specific growth variability based on an international (10 countries), multi-species (8 species) tree-ring width network encompassing 22 sites. To estimate the effect of direction-specific growth variability on climate-growth relationships, we applied a combination of three methods: An analysis of signal strength differences, a Principal Component Gradient Analysis and a test on the direction-specific differences in correlations between indexed ring-widths series and climate variables. We found no evidence for systematic direction-specific effects on tree radial growth variability in high-pass filtered ring-width series. In addition, direction-specific growth showed only marginal effects on climate-growth correlations. These findings therefore indicate that there is no consistent bias caused by coring direction in data sets used for diverse dendrochronological applications on relatively mesic sites within forests in flat terrain, as were studied here. However, in extremely dry, warm or cold environments, or on steep slopes, and for different life-forms such as shrubs, further research is advisable.</p

    Proposition of a large-scale mistletoe inventory method

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    Mistletoe (Viscum album L.) is a semi−parasitic plant and, as long as it is not present in large quantities, it does not pose a lethal threat to trees. Due to its ability to carry out photosynthesis, its effect on the host is negligible. However, recent droughts have made heavy impact on forests and mistletoe in recent years began to appear on a larger scale in regions and in places where it has never been a threat before. For this reason, there is an urgent need to broaden our knowledge about this species. This work includes a review of the literature on the biology and ecology of mistletoe. The main purpose of this research is to analyze the methods for assessing the number of mistletoe on individual trees and in the stands as well as to prepare new method adapted to Polish conditions. New method that was proposed is based on random sample plots, each consisting of 15 trees on which impact of mistletoe is assessed. On every sample plot the mistletoe occurrence, location in the crown, estimate of the percentage within the crown and the number of mistletoe on a tree is assessed. In addition, for further analysis, information on stand (forest habitat type, site index) as well as measured trees (age, diameter, Kraft class, crown length, loss of assimilation apparatus, crown type) levels is recorded

    Effect of hyperbary on chosen parameters of oxidative stress in diver's blood

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    Celem badań była ocena wpływu ekspozycji w komorze hiperbarycznej na wybrane parametry stresu oksydacyjnego we krwi nurków. Materiał i metody: W badaniach wzięło udział 10 zdrowych mężczyzn (niepalących, z doświadczeniem w nurkowaniu na duże głębokości) w wieku od 18 do 40 lat (średnia wieku 27 lat), którzy zostali poddani ekspozycji hiperbarycznej symulującej warunki ciśnieniowe panujące podczas nurkowania na głębokość 30 m. Grupę kontrolną stanowiło 16 zdrowych mężczyzn, którzy nigdy nie nurkowali. Osoby te nie były wcześniej poddawane ekspozycji hiperbarycznej. Krew do badań pobierano na czczo, z żyły odłokciowej. Oznaczano aktywność dysmutazy ponadtlenkowej (SOD-1) i stężenie dialdehydu malonowego (MDA) w krwinkach czerwonych, stężenie grup karbonylowych w białku oraz stężenia azotanów/azotynów w osoczu. Wyniki: Stwierdzono, że w grupie osób nurkujących stężenie MDA w erytrocytach różniło się istotnie statystycznie w porównaniu z grupą kontrolną. Nie stwierdzono istotnej statystycznie różnicy w stężeniu grup karbonylowych między grupą kontrolną a grupą nurków. W osoczu nurków stwierdzono znamiennie niższe stężenie azotanów/azotynów, a w krwinkach czerwonych istotnie niższą aktywność SOD-1 w odniesieniu do grupy kontrolnej. Po ekspozycji hiperbarycznej grupy nurków stwierdzono w erytrocytach znamienny wzrost stężenia MDA i istotny wzrost aktywności SOD-1, a w osoczu istotny wzrost stężenia azotanów/azotynów oraz znamiennie podwyższone stężenie grup karbonylowych w białku. Wnioski: W krwinkach czerwonych osób narażonych na działanie hiperbarii stwierdzono osłabioną enzymatyczną obronę antyoksydacyjną, w porównaniu z osobami przebywającymi w normobarii. We krwi nurków warunkach ekspozycji hiperbarycznej dochodzi do nasilenia stresu oksydacyjnego.The purpose of the study was to evaluate influence of hyperbaric expositions in chambers on chosen parameters of oxidative stress in divers' blood. Materials and methods: 10 healthy men (non-smoking, with experience in diving on large depths) in age from 18 till 40 years (mean age 27 years) took part in the investigations. Subjects were submitted on hyperbaric conditions. Expositions simulated conditions dominant at 30 m depth. Control group consisted of 16 healthy men, which have never dived nor have been exposed on hyperbaric conditions. Blood was taken after overnight fasting from cubital vein. Superoxide dismutase (SOD-1) activity and concentration of malondialdehyde (MDA) were marked in red blood cells, concentration of carbonyl groups in serum proteins, and concentration of nitrate/nitrite were estimated in plasma. Results: In group of divers MDA concentration in erythrocytes differed statistically in comparison with control group. Not statistically significant differences were estimated in carbonyl groups concentrations between divers group and control group. Concentration of nitrite/nitrate in plasma, as well as activity of SOD-1 in red blood cells decreased significantly, in comparison with control group. After hyperbaric expositions in test group MDA concentration in erythrocytes considerably increased, and also significant increase in SOD-1 activity was observed. In plasma significant increase in concentration of nitrite/nitrate was estimated, as well as increase in carbonyl groups in serum proteins

    Investigations of hydroxyapatite nanocomposites against anaerobic bacteria

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    Nanocrystalline apatites Ca10(PO4)6(OH)2 (HAp) non-doped and doped with Ag+ and Eu3+ ions were synthesized by different wet chemistry methods. The obtained hydroxyapatite was loaded with Ag0, as well as nitroimidazole antimicrobials: metronidazole and tinidazole. The antimicrobial activity of the obtained materials against Prevotella bivia and Parabacteroides distasonis was studied. The method used for the antibacterial susceptibility testing was broth microdilution, according to the CLSI – Clinical and Laboratory Standard Institute – standard M11-A8; agar Schaedler, enriched with 50% LHB - Lysed Horse Blood, was used as a medium for culturing strains. The antibacterial activity increased for the immobilized antibiotics – HAp doped with metronidazole and tinidazole was six times more bactericidal than non-immobilised metronidazole for both clinical isolates. In comparison with non-immobilised tinidazole, HAp immobilised with tinidazole was six thousand times more effective against P. distasonis and two hundred times more effective against P. bivia. HAp doped with tetracycline was over two times more bactericidal than tetracycline non-immobilised (according to the literature data). The exact MIC for bionanocomposites of HAp and silver was not obtained. The research shows that bionanocomposites of hydroxyapatite are good drug carriers for both antibiotics and silver particles and ions. The use of bionanocomposites of apatite immobilised with antibiotics in dentistry could result in a prolonged antibacterial activity of these compounds

    Zmiana liczby małych zbiorników wodnych na obszarze zlewni Rowu Wyskoć w latach 1980-2003 i charakterystyka nowo wykopanych zbiorników wodnych

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    The article presents the results of analyses of changes in the number of ponds in the Wyskoć catchment basin carried out in the years 1980-2003 and the characteristics of ponds excavated in that period. Only water reservoirs of an area less than 2 ha were considered. Analyses were based on topographic maps in the scale of 1:10 000 and aerial photographs taken in 1996. The results indicated that the number of filled ponds increased, especially those located in fields and grasslands. However, forest and wetland ponds were the most resistant to the processes of quantitative degradation because not even a single pond was filled during the analysed period. Over 70% newly excavated water bodies were made as an effect of exploitation of mineral and peat resources. However, nowadays ponds are more often created as a result of intentional human activities and are used for fish farming, recreation and as water retention reservoirs used in irrigation of small agricultural and gardening areas.W artykule przedstawiono wyniki analiz zmian liczby małych zbiorników wodnych na obszarze zlewni rowu Wyskoć w latach 1980-2003 oraz wybrane charakterystyki zbiorników wodnych wykopanych w tym okresie. Analizie poddano wyłącznie zbiorniki małe o powierzchniach poniżej 2 ha. Wszelkie analizy wykonywano na podstawie map topograficznych w skali 1:10 000 oraz zdjęć lotniczych z 1996 r. Uzyskane wyniki jednoznacznie wskazują, że liczba małych zbiorników wodnych w zlewni rowu Wyskoć się zwiększa. Jest to szczególnie widoczne w przypadku zbiorników zlokalizowanych na polach uprawnych i użytkach zielonych. W znacznie mniejszym stopniu zwiększyła się liczba zbiorników śródleśnych oraz zbiorników zlokalizowanych na mokradłach. W analizowanym okresie nie zasypano ani jednego zbiornika zlokalizowanego w lesie bądź na terenie podmokłym, tak więc stwierdzić można, że zbiorniki zlokalizowane na tych użytkach są najbardziej odporne na procesy degradacji ilościowej. Bezpośrednią przyczyną wykopania około 70% zbiorników wodnych była eksploatacja surowców mineralnych (żwiru, pospółki, gliny), bądź torfu. Obecnie jednak małe zbiorniki wodne są coraz częściej tworzone w wyniku celowych działań, jako zbiorniki przeznaczone do hodowli ryb, wędkarstwa, rekreacji, lub jako zbiorniki retencyjne wód wykorzystywanych do małoobszarowych nawodnień rolniczych i ogrodniczych

    Forest stands acquired from the State Land Fund – the condition and management problems

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    In this paper, we present problems with the management of the forests acquired by the State Forests from the State Land Fund. This was particularly an issue in forest districts with a significant share of private forests, e.g. eastern part of Poland. The problem becomes more and more valid because of the latest amendment of the Forest Act in 2016. It gives the State Forests the right of the first purchase of private forests attributed to sale. They may receive forest stands that will generate specific economic problems related to care, conservation, felling maintenance, etc. These are mostly stands with typical features of private forests, resulting from abandoning economic operations, selective acquisition, as well as from the size, shape and neighbourhood of the plots. This study presents the characteristics of almost 2,000 tree stands acquired from the State Land Fund between 1992−2016 by the Siedlce Forest District (SFD), which is a part of the Regional Directorate of the State Forests in Warsaw. SFD has low forest cover (18%), a strong fragmentation of forest complexes and a very large share of private forests (over 75%). The analysis was based primarily on the descriptions of forest stands and the quantitative and qualitative characteristics, presenting at the same time the problems that SFD has with conducting rational forest management in acquired plots. The current status of the forests transferred from the State Land Fund was assessed as unsatisfactory. The main problems in local conditions are: (i) inadequate fixation in acquired parcels next to private forests (difficulty in locating treatments and custody over the State property), (ii) depleted tree stands, (iii) inadequate parcels (too narrow) and (iv) complications related to co−ownership of parts seized plots. The need to carry out joint−assembly works (mainly land consolidation) or to introduce land communities that would facilitate the management of these forests was demonstrated
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