Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L.

<p>Abstract</p> <p>Background</p> <p>The St John's Wort (<it>Hypericum perforatum</it>; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.</p> <p>Results</p> <p>An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC₅₀of 0.52 μg/ml), NO scavenging (6.11 μg/ml), superoxide scavenging (1.86 μg/ml), lipid peroxidation (0.0079 μg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.</p> <p>Conclusion</p> <p>LC-MS technique has been successfully applied for a quick separation and identification of the major components of <it>H. perforatum </it>fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, <it>H. perforatum </it>preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).</p

Functional role of different habitat types at local and landscape scales for aphids and their natural enemies

The functional roles of different habitats may depend on the combined effect of local habitat management and the structure and composition of the surrounding landscape. However, this interaction is not well understood due to the common practice of pooling many different habitat types in one simple landscape metric (e.g., percentage crop area). In this study, we investigate the interactive effects of local and landscape factors on the abundance and species richness of aphids and their natural enemies, as well as primary parasitism and hyperparasitism rates. We selected 41 fields in Central Serbia with three disturbance levels at the local scale (wheat fields, alfalfa fields, and fallows) embedded in 15 landscapes that varied in percentage of annual crops, grasslands, and shrublands. We found ecosystem disservices to be promoted in wheat fields, where both aphid abundances and hyperparasitism rates were approximately threefold higher than in alfalfa fields and fallows. Concurrently, alfalfa fields supported at least twofold higher primary parasitism rates and predator (coccinellid) abundances than either wheat fields or fallows. The proportion of grasslands in the surrounding landscape had no effect on any organism group while shrublands appear to be important for both polyphagus predators and pests in some crops, a pattern not revealed when all semi-natural habitats in the landscape are pooled together. Our results imply that the roles of different habitat types at both local and landscape scales should be considered in a multifunctional agricultural management approach, which if adopted may provide better ecosystem services for multiple agroecosystem types

Parasitic eye infection by Ascaris lumbricoides: Case report

The parasitic infection is an affection of the body as well as the eye with parasites, protozoa's, worms and ectoparasites, with world incidence of 30%. These diseases are chronic, systemic diseases because of weak innate immunity and ability of parasites to evade immune answer of the host or increasing the resistance to the adaptive immunity of the host. Parasites can evade immunity of the host by: antigens variations, forming cysts, changing the hosts and by synthesis of some cytokines, which decrease immunity of the host. Ascaris lumbricoides is the largest intestinal nematode parasitizing man. The worm is known to cause subconjunctival mass, granulomatous iridocyclitis, choroiditis, recurrent vitreous hemorrhage, chronic dacryocystitis and invasion into the subretinal space. The goal of this case was to analyze the affection of the eye, caused by the Ascaris lumbricoides as very rare ocular pathology

Supercritical and high pressure subcritical fluid extraction from Lemon balm (Melissa officinalis L., Lamiaceae)

Analysis of yield and composition profile of Melissa officinalis (Lemon balm) extract obtained by two-step CO2 extraction at high pressure was analyzed. The first or essential oil fraction, collected at 10 MPa and 40 degrees C, contained mostly the high volatile and aromatic compounds. The second fraction was consenquently extracted at 30 MPa using different temperature: 25 degrees C (higher pressure than critical pressure but at temperature below the critical; HPCP-CO2), 40 degrees C or 100 degrees C (supercritical CO2; SC-CO2). Obtained yield of essential oil fraction was 0.45% at 10 MPa, while depending on applied extraction temperature (HPCP-CO2 or SC-CO2), the yields of the second fractions collected at 30 MPa varied from 0.44% to 0.94%. Within the study, the content of active substances in obtained extracts was analyzed, too. For comparison with CO2 extracts (HPCP or SC) the yield and characterization of essential oil obtained by hydrodistillation was accomplished, as well. A significant difference was noted not only between the essential oil isolated by hydrodistillation and SC-CO2 extraction (40 degrees C, 10 MPa) but also between total extracts obtained by HPCP-CO2 and SC-CO2 extraction. The pseudo kinetic model was applied to define SC-CO2 extraction of Lemon balm to describe the relation between the yield of extraction and CO2 consumption. Antioxidant activity of obtained extracts was determined by free radical scavenging capacity (RSC) and significant correlation of antioxidant capacity and composition profile between obtained extracts was observed

Assessment of volemia status using ultrasound examination of the inferior vena cava and spectroscopic bioimpendance in hemodialysis patients

Background/Aim. Hypervolemia is an important risk factor for the development of cardiovascular morbidity and mortality in patients treated with regular hemodialysis. There is still no reliable method for assessing the status of volemia in these patients. The aim of the study was to assess the status of volemia in patients treated with regular hemodialysis by measuring the parameters of the inferior vena cava (IVC) and bioimpedance. Methods. The effect of hemodialysis treatment on ultrasound parameters of the IVC, as well as on the parameters measured by bioimpedance, was examined before and after hemodialysis. The values of the N-terminal prohormone of brain natriuretic peptide (NT-proBNP) were measured both before and after hemodialysis. Forty-five patients were involved in this non-interventional cross-section study, including the patients treated with standard bicarbonate dialysis. According to the interdialytic yield, the patients were divided into three groups: I (up to 2,000 mL), II (2,000–3,000 mL), and III (over 3,000 mL). Results. The values of the IVC parameters and the parameters measured with bioimpedance were significantly lower after treatment with hemodialysis (p < 0.005). The third group of patients had a significantly higher total fluid volume in the body com-pared to the group I, as well as a significantly greater volume of extracellular fluid (p < 0.005). The significantly lower values of NT-proBNP in all groups (p < 0.005) were detected after hemodialysis. After treatment with hemodialysis, a positive correlation was observed between the concentration of NT-proBNP in the serum and the extracellular/intracellular water ratio. However, the correlation between NT-proBNP concentration and total fluid measured by bioimpedance spectroscopy did not reach statistical significance. Conclusion. Measurement of the IVC ultrasound parameters and volemia parameters using bioimpedance significantly contributes to the assessment of the status of volemia. Nevertheless, it cannot be used as a separate parameter, only in combination with all other methods

The quality of coal and hydrogeological characteristics in deposit 'Delići and Peljave-Tobut' near Ugljevik

Geological study of 'Delici and Peljave - Tobut' coal deposit, located in north-eastern part of the Republic of Srpska (B&H), has given a new insight into geological structure of coal-bearing series and quality of coal. Coal-bearing series was formed in a lower Miocene lake and has complex geological-tectonic structure and litho-facial diversity. Two coal seam are identified within this series - the older one, so-called the Main coal seam (developed throughout the deposit; with major coal reserves) and the younger one - Upper coal seam, which is of a restricted areal extent. Coal from this deposit has a variable ash content -34.91% on average in the Main seam and 44.58% on average in the Upper seam. This coal has an average sulfur content of 3.73% in the Main seam and 2.73% in the Upper seam. An average moisture content is 19.07% in the Main seam and 18.26% in the Upper seam. An average lower heating value is 111.671 kJ/kg for the Main seam and 7.952 kJ/kg for the Upper seam. Petrographic study of coal have shown that the coal of this deposit has high content of huminite, increased content of liptinite, low content of inertinite and increased content of mineral matter. Densinite is a dominant maceral of huminite group, while ulminite is less abundant. The content of other macerals of this group is low

Reducing Risks in Energy Innovation Projects: Complexity Theory Perspective

The aim of this paper is to contribute to existing work on project risk management, and energy innovation projects, using the lens of complexity theory. By regarding energy innovation projects as complex adaptive systems, and linking complexity theory elements to the possibilities for reducing risks of energy innovation projects, the authors conducted empirical research on a representative sample of 100 subjects. The authors used a questionnaire that was formed on the basis of a previously designed research model, which unifies several different management fields, and a large number of phenomena previously studied independently. Therefore, it has a holistic approach to the topic. The results of this research suggest that considering the elements of complexity theory had a positive impact on reducing risks in energy innovation projects, in all analyzed aspects including specific, operational, and especially regarding social and behavioral aspects. This paper strives to support and encourage better results in energy innovation projects by reducing their risks, and hopes to bring additional value by introducing a new risk philosophy, based on complexity theory. Lessons learnt regarding each issue of this research are points of concern for project managers

Mixed ligand Co(II), Ni(II) and Cu(II) complexes containing terephthalato ligands. Crystal structures of diaqua(2,2 '-dipyridylamine)(terephthalato)metal(II) trihydrates (metal = cobalt or nickel)

A series of nine ternary Co(II), Ni(II) and Cu(II) complexes with some aromatic diamines and dianion of terephthalic acid (tpht) have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements, IR and diffuse-reflectance spectroscopy. All compounds were obtained as microcrystalline solids, stable in air and insoluble in common solvents. Two of them, [M(tpht)(dipya)(H2O)(2)]. 3H(2)O [M = Co(II), Ni(II); dipya = 2,2'-dipyridylamine], were obtained as single crystals and their crystal structures have been determined by X-ray structure analysis. Both structures consist of discrete [M(tpht)(dipya)(H2O)(2)](2+) complex units with two H2O molecules in the trans position. Three additional H2O molecules together with coordinated H2O and O atoms from COO groups make a three-dimensional network of hydrogen bonds. Terephthalato ligands are coordinated by only one COO group, which acts as a chelating ligand. Central metal ions are in a distorted octahedral environment. Based on the above-mentioned analysis and known crystal structures, the possible structures and geometry of the complexes are discussed. All Co(II) and Ni(II) complexes are pseudooctahedral and mononuclear, with only one of the tpht COO groups coordinated in a chelate mode. Cu(II) complexes have probably distorted octahedral geometry with bridging role of tpht ions and monodentate or strongly asymmetric coordination of COO groups

Ranjivost poljoprivrede na klimatske promene u Srbiji - procena uticaja i šteta po mišljenju poljoprivrednika

Considering the already observed trends of increasing air temperatures, changes in precipitation regimes, and extension of the growing season, as well as predictions that climate conditions in Serbia will deteriorate and the risks to farming will increase, the objective of this research is to assess the vulnerability of agriculture in Serbia to climate change, based on farmers' perceptions. A team of experts in all areas of agriculture and soil and water management compiled a questionnaire for a semi-open online survey. The snowball sampling approach was followed, relying on personal contacts and social media. In total, 141 farmers responded to the questionnaire. The data were evaluated using descriptive statistics. The differences by region, activity and topography were tested by ANOVA and Student's t-test. The feedback was used to assess the damages sustained by farmers due to climate change and reduced revenues in their respective areas of agricultural activity. Certain positive effects of climate change were also identified. A need for training in climate change impact mitigation is noted. The collected data were analyzed by descriptive statistics. The surveyed farmers believe that the most important effects of climate change were periods of extreme high temperature, droughts, late spring frost, and hail. Climate change seems to be reducing yields, facilitating the appearance of new diseases and pests, and causing a lower tolerance to existing diseases and pests. Farmers expressed considerable interest in climate change impact adaptation and mitigation training.U skladu sa već osmotrenim trendovima povećanja temperature vazduha, izmenjenog režima padavina i produžetka vegetacione sezone, kao i sa predviđanjima da će se klimatski uslovi u Srbiji izrazito pogoršavati, a rizici u poljoprivrednoj proizvodnji povećavati, cilj ovog rada je da se proceni ranjivost poljoprivredne proizvodnje u Srbiji pod uticajem klimatskih promena na osnovu percepcije poljoprivrednika. Tim eksperata iz svih oblasti poljoprivrede i upravljanja vodama i zemljištem, sastavio je pitanja za onlajn anketu, poluotvorenog tipa. Prikupljanje podataka je vršeno putem interneta, uglavnom se oslanjajući na društvene mreže. Na upitnik je odgovorio ukupno 141 ispitanik. Analiza podataka je vršena putem deskriptivne statistike, a primenjena je analiza glavnih komponenti (PCA) sa Varimax rotacijom. Uočena su dva faktora: (i) uticaj klimatskih promena na rizike u poljoprivredi, i (ii) šteta izazvana klimatskim promenama. Analiza varijanse (ANOVA) i Studentov t test korišćeni su za ispitivanje uzoraka nezavisnih od razlike, dok je povezanost dve promenljive testirana Pirsonovim koeficijentom. Na osnovu dobijenih podataka, analizirane su štete koje poljoprivrednici trpe usled klimatskih promena i smanjenje prihoda u odnosu na uobičajene prihode, a shodno proizvodnji kojom se poljoprivrednici bave. Takođe su identifikovani pozitivni uticaji klimatskih promena. Sagledana je potreba za obukom u oblasti ublažavanja uticaja klimatskih promena. Po mišljenju poljoprivrednika, najznačajniji uticaji klimatskih promena su pojave ekstremno visoke temperature, suša i pojava kasnih prolećnih mrazeva i grada. Klimatske promene su se najviše odrazile na pad prinosa, pojavu novih bolesti i štetočina i na smanjenje tolerantnosti useva na postojeće štetočine i bolesti. Poljoprivrednici su pokazali veliku zainteresovanost za obuku o merama adaptacije i ublažavanja uticaja klimatskih promena u poljoprivredi

Design of co-existence parallel periodic surface structure induced by picosecond laser pulses on the Al/Ti multilayers

Formation of periodic nanostructures on the Ti/5x(Al/Ti)/Si multilayers induced by picosecond laser pulses is studied in order to better understand the formation of a laser-induced periodic surface structure (LIPSS). At fluence slightly below the ablation threshold, the formation of low spatial frequency-LIPSS (LSFL) oriented perpendicular to the direction of the laser polarization is observed on the irradiated area. Prolonged irradiation while scanning results in the formation of a high spatial frequency-LIPSS (HSFL), on top of the LSFLs, creating a co-existence parallel periodic structure. HSFL was oriented parallel to the incident laser polarization. Intermixing between the Al and Ti layers with the formation of Al-Ti intermetallic compounds was achieved during the irradiation. The intermetallic region was formed mostly within the heat affected zone of the sample. Surface segregation of aluminium with partial ablation of the top layer of titanium was followed by the formation of an ultra-thin Al2O3 film on the surface of the multi-layered structure. Published by AIP Publishing