The effect of European black alder (Alnus gluiinosa L.) on the contents of carbon and nitrogen, exchangeable base cations, and plant available forms of phosphorus in the reclaimed mine soils formed ...by waste deposition from opencast lignite mines was researched in central Serbia. It was concluded that the greatest part of dead organic residues reaching the soil under European black alder monocultures was liable to rapid decomposition into end products. This was the consequence of a narrow C/N ratio in the European black alder litterfall which amounted on average to 12.77 in the study monocultures. Only a small part of organic residues was transformed into humus. On that account. European black alder monocultures did not have a major impact on the accumulation of organic carbon and total nitrogen in the soil. The content of carbon in the surface layers accounted for 1.55-1.57%. and the content of nitrogen to 0.085-0.132%. Fast mineralisation of organic matter, and thus also of the organic forms of nitrogen, resulted in the surplus of soil nitrates, which were liable to washing through the soil. Nitrate movement resulted in the soil leaching and the movement of base cations, primarily calcium, to the deeper layers of the solum. The total soil phosphorus content was low, and also the level of plant available forms. A significant portion of total phosphorus in the surface layers of the reclaimed mine soils was composed of its organic forms.
The aim of the study is to establish, based on the morphological characteristics of shoots and morpho-anatomical characteristics of needles as well as the content of micro-elements in needles, ...whether there are differences between Pyramidal Fir (Abies alba var. pyramidalis Carr.) and European Silver Fir (Abies alba Mill.), and between Mišić’s spruce (Picea abies var. misicii Matović & Pavlović) and Common Spruce (Picea abies (L.) Karst.), and to determine in which characteristics these differences are most pronounced. This study showed that Pyramidal fir (PF) has a two-times higher number of lateral shoots in comparison to European silver fir (ESF), but also shorter and thinner shoots and a lower number of needles, which are slightly less densely distributed on a shoot. In addition, PF terminal shoots are significantly longer and thicker than the lateral, and have a higher number of needles. Two-year-old PF needles are longer, wider and thicker in comparison to ESF needles, and have higher values with respect to diameter of the central cylinder, thickness of cuticle and epidermis, thickness of hypodermis and diameter of resin canals. The most pronounced differences between PF and ESF are related to length of shoots, needle width and diameter of the central cylinder (statistically significant differences). In comparison to ESF, PF has a higher percentage of nitrogen, phosphorus and potassium in needles; however, this is statistically significant only in case of phosphorus. The most apparent morphological specificity of Mišić’s spruce (MS) is a rare occurrence of lateral shoots (only once in several years), unlike Common spruce (CS), which has 2-3 new shoots every year. MS has far longer and thicker shoots, while its needles are more numerous, longer, thinner and more densely distributed on the shoot in comparison to CS. Additionally, in comparison to CS, MS needles have a larger diameter of central cylinder, but lower thickness of cuticle with epidermis, lower thickness of hypodermis and smaller diameter of the resin canals. The most pronounced differences between MS and CS are related to length, width and thickness of needles and diameter of central cylinder (statistically significant differences). In comparison to CS, MS has a higher percentage of nitrogen, phosphorus and potassium in needles; however, this is not statistically significant.
The results of studying inhibitory effect of streptomycin on the modified Berthelot reaction were presented in this paper and a new kinetic method for determining streptomycin in pharmaceutical ...preparations and human urine was developed on the basis of the obtained results. The rates of catalytic and catalytic-inhibitory reaction were monitored at 700 nm （t=25 ±0.1 ℃） using UV/vis spectrophotometer. By analyzing the spectra and experimental dependences of the catalytic and catalytic-inhibitory reaction rates on the reactant concentrations, it was noticed that streptomycin attacked nitroprusside and hypochlorite causing the inhibition of the production of 2,2＇-dicarboxylindophenol. According to this effect, an analytical decrease for determination of urea by modified Berthelot reaction appeared in the presence of small amounts of streptomycin. Beer＇s law was obeyed in the interval of streptomycin sulfate concentration from 18.2 to 182 μg·mL^-1. The detection limit calculated by two methods was obtained at 11.75 μg·mL^-1 and 8.54 μg·mL^-1. The relative standard deviation of 0.55%--8.83% and the recovery of 109.10% were determined. The obtained results were validated using the referent HPLC method.
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In light of the increase of environmental pollution, we tested the effect of cadmium (Cd) and lead (Pb) soil contamination on ash dieback. The experiment included the inoculation of Hymenoscyphus ...fraxineus on Fraxinus excelsior and Fraxinus angustifolia seedlings growing on unpolluted soil, soil contaminated with cadmium (Cd), and soil contaminated with lead (Pb). At the end of the experiment, 173 days after soil contamination and 50 days since inoculation, all F. excelsior and F. angustifolia seedlings inoculated with H. fraxineus showed ash dieback symptoms in comparison to their control groups. However, both F. excelsior and F. angustifolia seedlings grown on contaminated soil had significantly increased necrotic lesions in comparison to the seedlings grown on uncontaminated soil. Our results showed for the first time that cadmium (Cd) and lead (Pb) soil contamination can significantly contribute to ash dieback and increase damage to F. excelsior and F. angustifolia seedlings.
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Perception of Corporate Social Responsibility (CSR) forms relating to perception of company performance was analysed for Serbia. Questionnaire-based research was conducted with employees from public, ...private and multinational companies. Employees` age was indicator of socialist experience. Different perception of CSR forms from those in Carrol`s pyramid was observed, as well as between endogenous CSR forms of the socialist period and exogenous from the open market economies. Results indicate economic and legal forms are perceived more expressed, regardless of companies` management, than ethical and discretional. Endogenous ethical CSR are perceived less expressed than exogenous. Unexpectedly, socialist experience did not significantly influence perception, regardless of companies` management and CSR forms.
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The kinetic method is based on a catalytic effect on the oxidation of sodium pyrogallol-5-sulfonate by hydrogen peroxide. The reaction is followed spectrophotometrically at 436.8 nm. The kinetic ...parameters of the reaction are reported and a rate equation is suggested. The calibration graph is linear in the range 10 - 200 ng cm-3. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. This method has high sensitivity and good selectivity when anions are concerned as well. That is why it can be successfully applied to determination of iodide in real samples (mineral water and soil) directly after the elimination of cations, which interfere. The method was applied to determine iodide in natural waters and soil.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantification of doxycycline hyclate in pharmaceutical samples has been developed and validated. ...The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm x 4.6 mm, 10 mm particle size) at 20?C with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous solution of oxalic acid (2:3:5, v/v/v). The flow rate was 1.25 ml min-1. A UV detector set at 350 nm was used to monitor the effluent. Each analysis required no longer than 4 min. The limits of detection and quantification were 1.15 and 3.84 ?g ml-1, respectively. Recoveries for different concentrations ranged from 99.58 to 101.93%.
Tacna, osetljiva i reproduktivna metoda visoko efektivne tecne hromatografije (HPLC) za kvantifikaciju doksiciklin-hiklata u farmaceutskim uzorcima je razvijena i potvrdjena. Lek i standard su eluirani sa kolone Lichrosorb RP-8 (250 mm x 4,6 mm, velicine cestice od 10 mm) na 20?C sa mobilnom fazom koja se sastojala od metanola, acetonitrila i 0,010 M vodenog rastvora oksalne kiseline (2:3:5, v/v/v). Brzina protoka je bila 1,25 ml min-1. Za pracenje efluenta koriscen je UV detektor podesen na 350 nm. Svaka analiza je trajala ne duze od 4 minuta. Granica detekcije je 1,15, dok je granica kvantifikacije 3,84 ?g ml-1. Efikasnost za razlicite koncentracije se krece od 99,6 do 101,9 %.
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Kinetic determination of morin nanoamounts Kostic, Danijela; Mitic, Snezana; Miletic, Gordana
Journal of the Serbian Chemical Society,
01/2004, Volume:
69, Issue:
6
Journal Article
Peer reviewed
Open access
kinetic-spectrophotometric method is proposed for the determination of morin. The method is based on the inhibition effect of morin on the oxidation of C6H5COON aby hydrogen peroxide in the presence ...of the complex Fe(II)-AA(ascorbic acid),which acts as a catalyst. The concentration range for the determination of morin is one of the lowest achieved so far (a linear calibration graph was obtained for morin from 2.255?22.55 ng cm-3). The limit of detection of the method is 0.28 ng cm-3. The relative error ranges between 1.42 to 5.10% for the given concentration interval. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined in order to assess the selectivity of the method. The major advantages of this kinetic-spectrophotometric assay are its sensitivity, selectivity, reproducibility, speed and simplicity.
Predlozena je nova kineticko-spektrofotometrijska metoda za odredjivanje morina. Metoda se zasniva na inhibicionom efektu morina na oksidaciju natrijum benzoata vodonik- peroksidom u kiseloj sredini u prisustvu kompleksa Fe(II)-AA(askorbinska kiselina), koji ima ulogu katalizatora. Granica detekcije je 0,28 ng cm?3. Relativna greska metode se krece od 1,42?5,1%za koncentracioni interval u opsegu od 2,255?22,55 ng cm?3. Postavljene su kineticke jednacine za ispitivane procese. Radi ocene selektivnosti ispitan je uticaj veceg broja stranih jona i organskih molekula na brzinu reakcije. Reakcija je visoko selektivna prema neorganskim anjonima i katjonima. Glavne karakteristike ove metode su visoka osetljivost, selektivnost reproduktivnost, brzina izvodjenja i jednostavnost.
Legal foundations for training electricians for live work (LW) differ amongst individual countries. In some places, it is included in education and in others, it is part of the health and safety at ...work. Some countries regulate it on the level of national agencies and others on the company level. Basic training includes theoretical and practical training in specialised educational centres and polygons with the technical equipment for carrying out the practical programme of LW. Professional literature and manuals talk about the recommended extent of individual initial LW programmes for different voltage levels (HV, MV, LV) and periodical training for the competency sustenance. This paper describes the concepts of training for LW on LV in Slovenia and Croatia, where the legal foundations differ but the training programmes are similar because the training manuals for LW on LV are practically identical and both countries carry out the basic training on the polygon HEP NOC.
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