169 research outputs found
The influence of chemical characteristics of precipitation on tree health in Banjica Forest (Belgrade, Serbia)
The most represented tree species in the Banjica Forest are Acer negundo, Quercus robur, Acer pseudoplatanus, Populus nigra, Fraxinus pennsylvanica, Fraxinus ornus and Robinia pseudoacacia. According to the ICP Forests combined assessment (degree of defoliation and decolorization), endangered species are Populus nigra (64.3% of heavily damaged trees), Quercus robur (45.5%), Fraxinus pennsylvanica (37.0%) and Acer negundo (26.6%), while the situation is much better for Acer pseudoplatanus and Fraxinus ornus. For Robinia pseudoacacia, 83% of trees are without decolorization, however, defoliation is established. In the period from April to October 2009, the average pH of rainwater was 5.46, and 5.18 in the period from November 2009 to March 2010. The concentration of SO42- in the period from April to October 2009 amounted to an average of 24.21 mg/l, and 28.87 mg/l in the period from November 2009 to March 2010. The concentration of SO42- and pH values is a possible explanation for the condition of the trees. [Acknowledgments. The results are a part of the project III47007 funded by the Ministry of Education and Science of the Republic of Serbia.
Spectrophotometric and uplc study of reaction between [AuCl4] - and quercetin
The equilibrium and kinetics of the reaction between tetrachloroaurate(III) ion (AuCl4 - ) and quercetin in 0.1 M HClO4 were studied spectrophotometrically. The fast and the slow reaction steps were distinguished in the reaction mechanism, depending on the ratio of AuCl4 - and quercetin concentration. The stoichiometry of reaction, determined by molar ratio and Jobbās methods, was 1:1. The kinetics of complex formation was followed under the pseudo-first order conditions by measuring the absorbance at 294 nm vs. time as the function of quercetin concentration in 5 ā 15 fold excess.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200
Theoretical and experimental analysis of dynamic processes of pipe branch for supply water to the Pelton turbine
The paper presents the results of the analysis of pipe branch A6 to feed the Hydropower Plant āPeruÄicaā with integrated action Pelton turbines. The analysis was conducted experimentally (tensometric) and numerically. The basis of the experimental research is the numerical finite element analysis of pipe branch A6 in pipeline C3. Pipe branch research was conducted in order to set the experiment and to determine extreme stress states. The analysis was used to perform the determination of the stress state of a geometrically complex assembly. This was done in detail as it had never been done before, even in the design phase. The actual states of the body pipe branch were established, along with the possible occurrence of water hammer accompanied by the appearance of hydraulic oscillation. This provides better energetic efficiency of the turbine devices. [Projekat Ministarstva nauke Republike Srbije, br. TR35049 and br. TR 33040
The influence of chemical characteristics of precipitation on tree health in Banjica Forest (Belgrade, Serbia)
The most represented tree species in the Banjica Forest are Acer negundo, Quercus robur, Acer pseudoplatanus, Populus nigra, Fraxinus pennsylvanica, Fraxinus ornus and Robinia pseudoacacia. According to the ICP Forests combined assessment (degree of defoliation and decolorization), endangered species are Populus nigra (64.3% of heavily damaged trees), Quercus robur (45.5%), Fraxinus pennsylvanica (37.0%) and Acer negundo (26.6%), while the situation is much better for Acer pseudoplatanus and Fraxinus ornus. For Robinia pseudoacacia, 83% of trees are without decolorization, however, defoliation is established. In the period from April to October 2009, the average pH of rainwater was 5.46, and 5.18 in the period from November 2009 to March 2010. The concentration of SO42- in the period from April to October 2009 amounted to an average of 24.21 mg/l, and 28.87 mg/l in the period from November 2009 to March 2010. The concentration of SO42- and pH values is a possible explanation for the condition of the trees
Eight new Halophytophthora species from marine and brackish-water ecosystems in Portugal and an updated phylogeny for the genus
During an oomycete survey in December 2015, 10 previously unknown Halophytophthora taxa were isolated from marine and brackish water of tidal ponds and channels in saltmarshes, lagoon ecosystems and river estuaries at seven sites along the Algarve coast in the South of Portugal. Phylogenetic analyses of LSU and ITS datasets, comprising all described Halophytophthora species, the 10 new Halophytophthora taxa and all relevant and distinctive sequences available from GenBank, provided an updated phylogeny of the genus Halophytophthora s.str. showing for the first time a structure of 10 clades designated as Clades 1-10. Nine of the 10 new Halophytophthora taxa resided in Clade 6 together with H. polymorphica and H. vesicula. Based on differences in morphology and temperature-growth relations and a multigene (LSU, ITS, Btub, hsp90, rpl10, tigA, cox1, nadh1, rps10) phylo-geny, eight new Halophytophthora taxa from Portugal are described here as H. brevisporangia, H. cele-ris, H. frigida, H. lateralis, H. lusitanica, H. macrosporangia, H. sinuata and H. thermoambigua. Three species, H. frigida, H. macrosporangia and H. sinuata, have a homothallic breeding system while the remaining five species are sterile. Pathogenicity and litter decomposition tests are underway to clarify their pathological and ecological role in the marine and brackish-water ecosystems. More oomycete surveys in yet undersurveyed regions of the world and population genetic or phylogenomic analyses of global populations are needed to clarify the origin of the new Halophytophthora species.info:eu-repo/semantics/publishedVersio
Supplementary material for the article: MilenkoviÄ, I.; RadotiÄ, K.; MatoviÄ, B.; Prekajski, M.; ŽivkoviÄ, L.; JakovljeviÄ, D.; GojgiÄ-CvijoviÄ, G.; BeÅ”koski, V. Improving Stability of Cerium Oxide Nanoparticles by Microbial Polysaccharides Coating. Journal of the Serbian Chemical Society 2018, 83 (6), 745ā757. https://doi.org/10.2298/JSC171205031M
Supplementary material for: [https://doi.org/10.2298/JSC171205031M]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2087
Improving stability of cerium oxide nanoparticles by microbial polysaccharides coating
Cerium oxide (CeO2) nanoparticles (CONPs) are interesting biomaterials with various applications in biomedicine, cosmetics and the pharmaceutical industry, but with limited practical application because of their low stability in aqueous media. The aim of this study was to obtain CONPs with increased stability by coating the particles. Microbial exopolysaccharides (levan, pullulan) and glucose were used to prepare CONPs under different synthesis conditions. Coating was attempted by adding the carbohydrates during (direct coating) or after (subsequent coating) the synthesis of CONPs. The obtained nanoparticles were characterized by X-Ray diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The suspension stability of the uncoated and coated CONPs in aqueous media was evaluated by measuring the hydrodynamic size, zeta potential and turbidity. The FT-IR spectra revealed the differences between coated CONPs and showed the success of subsequent coating with carbohydrates. Coating with carbohydrates improved the stability the CONP suspension by decreasing the size of aggregated particles. The suspensions of levan- and glucose-coated CONPs had the best stability. In this study, CONPs were prepared using non-toxic materials, which were completely environmentally friendly. The obtained results open new horizons for CONP synthesis, improving their biological applications.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3207
An Introductory Guide to Aligning Networks Using SANA, the Simulated Annealing Network Aligner.
Sequence alignment has had an enormous impact on our understanding of biology, evolution, and disease. The alignment of biological networks holds similar promise. Biological networks generally model interactions between biomolecules such as proteins, genes, metabolites, or mRNAs. There is strong evidence that the network topology-the "structure" of the network-is correlated with the functions performed, so that network topology can be used to help predict or understand function. However, unlike sequence comparison and alignment-which is an essentially solved problem-network comparison and alignment is an NP-complete problem for which heuristic algorithms must be used.Here we introduce SANA, the Simulated Annealing Network Aligner. SANA is one of many algorithms proposed for the arena of biological network alignment. In the context of global network alignment, SANA stands out for its speed, memory efficiency, ease-of-use, and flexibility in the arena of producing alignments between two or more networks. SANA produces better alignments in minutes on a laptop than most other algorithms can produce in hours or days of CPU time on large server-class machines. We walk the user through how to use SANA for several types of biomolecular networks
Simultaneous Optimization of Both Node and Edge Conservation in Network Alignment via WAVE
Network alignment can be used to transfer functional knowledge between
conserved regions of different networks. Typically, existing methods use a node
cost function (NCF) to compute similarity between nodes in different networks
and an alignment strategy (AS) to find high-scoring alignments with respect to
the total NCF over all aligned nodes (or node conservation). But, they then
evaluate quality of their alignments via some other measure that is different
than the node conservation measure used to guide the alignment construction
process. Typically, one measures the amount of conserved edges, but only after
alignments are produced. Hence, a recent attempt aimed to directly maximize the
amount of conserved edges while constructing alignments, which improved
alignment accuracy. Here, we aim to directly maximize both node and edge
conservation during alignment construction to further improve alignment
accuracy. For this, we design a novel measure of edge conservation that (unlike
existing measures that treat each conserved edge the same) weighs each
conserved edge so that edges with highly NCF-similar end nodes are favored. As
a result, we introduce a novel AS, Weighted Alignment VotEr (WAVE), which can
optimize any measures of node and edge conservation, and which can be used with
any NCF or combination of multiple NCFs. Using WAVE on top of established
state-of-the-art NCFs leads to superior alignments compared to the existing
methods that optimize only node conservation or only edge conservation or that
treat each conserved edge the same. And while we evaluate WAVE in the
computational biology domain, it is easily applicable in any domain.Comment: 12 pages, 4 figure
Polyphenol rich extracts of Geranium L. species as potential natural antioxidant and antimicrobial agents
OBJECTIVE: Plants and plant extracts are of great scientific interest due to the
chemical diversity and pharmacological properties of present bioactive molecules. The Geranium L. species are widely used in ethnomedicine. In the current study, the total phenolic and
tannin content, antioxidant and antimicrobial
activity of methanol extracts of eight Geranium
species were investigated.
MATERIALS AND METHODS: The total phenolic and tannin content were determined by the
FC method. Antioxidant capacity was evaluated
in FRAP, DPPH, and biochemical assays, while
antimicrobial activity was examined using the
broth microdilution method.
RESULTS: The high total phenolic (170.64-
636.32 mg GAE/g dry extract) and tannin content (37.80-414.02 mg GAE/g DE), along with significant total antioxidant (FRAP values 1.13-8.80
mmol Fe2+/g) and DPPH radical scavenging activity (SC50 values 4.24-34.52 Āµg/mL) were observed. The prominent antioxidant capacity was
confirmed in biochemical assays (OS values -1.47
ā -13.02). The extracts exhibited significant antimicrobial activity against ATTC strains (MICs
dominantly in the range of 12.5-200 Āµg/mL) as
well as against clinical isolates of E. coli (MICs
mostly 50 and 100 Āµg/mL). The pronounced antioxidant and antimicrobial activity can be due to
the high phenolic content, particularly due to the
presence of hydrolyzable tannins.
CONCLUSIONS: Based on the high content of
polyphenols, pronounced antioxidant and antimicrobial activities, the examined extracts are
promising natural antioxidant and antimicrobial
agents with the potential medicinal purpose and
use as a functional food
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